Electric vehicle revolution cannot happen.......its proven...do you agree? - Page 1
Forum section: electronics / beginners

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 13, 2020, 01:02:41 pm
content: This video proves beyond all doubt , that the electric vehicle revolution will never happen..because its simply not practical to make peoples residential households safe to charge the vehicles.Due to grounding issues and the potential for a broken neutral in the supply.Do you agree?

author: Ice-Tea
author_rank: Super Contributor
timestamp: December 13, 2020, 01:48:19 pm
content: What a load of crock. Watched about half of it. The problem is that the earthing scheme sometimes used in the UK apparently is single-fault sensitive. Dragging EVs into this is far fetched at least. With the earth fault, there are a 1000 ways to get electrocuted around the house. With an EV charger installed, there's 1001. That's all.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 13, 2020, 01:59:17 pm
content: Total bollocks. Not worth commenting much because the burden of proof for extraordinary claims is with those making the claims, especially when it concerns things that anyone can see working just fine every day.

author: Cerebus
author_rank: Super Contributor
timestamp: December 13, 2020, 03:04:36 pm
content: All the video proves is that if you have a TN-C-S supply and you have a PEN fault you have a problem, full stop. That is true.Is it true that this prevents you fitting an EV charge point? Yes,if and only if, you similarly believe that a TN-C-S supply, with a potential for a PEN fault, is sufficient to prevent you from havinganyelectrical appliances.So treez (yes, we've worked out it's you), you appear to believe that this "proves beyond all doubt" that EV charging points are impractical and unsafe on the basis of potential PEN faults in TN-C-S supplies. Therefore the only logical conclusion is that in your opinionallelectrical appliances can't practically be made safe, so you should have the courage of your convictions and go and turn the mains power to you house off and pull the company fuses to ensure that your house is isolated from the 'unsafe' TN-C-S supply. It's a happy coincidence that this will also knock you offline and we won't have to listen to any more of this balderdash.

author: themadhippy
author_rank: Super Contributor
timestamp: December 13, 2020, 03:10:36 pm
content: QuoteTotal bollox,John ward is a highly respected electrical engineer,he isnt disproving anything,hes discussing the various methods of installing a charge point,or in fact any electrical supply outside of the equipotential zone,and the problems and pitfalls you face.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 03:29:35 pm
content: There are a number of EVSEs that have PEN fault detection built in, as well as external devices to provide the same protectionAnd there is also the option of adding a TT earth rod in many cases - an earth impedance as high as a few K would be enough to trip a 30mA RCD

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 13, 2020, 03:34:25 pm
content: I think JW goes through all available protections in the video....most are not adequate as he says.....he concludes you either need a three phase supply or spend 1000's digging your drive up to put in a earthing mesh....which he rightly concludes, people just wont want to do this...too expensive.JW rightly puts forward that an earth connection is not necessarily low enough impedance to actual earth.....its assumed to be...but often is not.And as JW describes, its simply not legal for most people to put in an earth rod...due to proximity to pipes etc....aswell as the situation with actual earth rod to earth impedance.JW is a respected engineer, and he has layed bare the situation as i have described. The regs are the regs. No EV's likely.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 03:40:29 pm
content: Quote from: opampsmoker on December 13, 2020, 03:34:25 pmMeanwhile the rest of the world just gets on with it.There might be some convoluted set of circumstances that might cause some risk, but that's true of virtually every electrical situation.You also have to apply some pragmatism - if the regs dictated some expensive solution, people would just use a granny charger on a dodgy extension lead and the odd fire would result, which is a far bigger risk.

author: Gyro
author_rank: Super Contributor
timestamp: December 13, 2020, 03:41:33 pm
content: Treez,As I pointed out to you in your other thread on lost Neutrals, PEN fault protectors are athing. In the case of decent intelligent chargers, like the myenergi Zappi, and I think, a few others, the PEN fault protection is built into the unit itself. Other dumb chargers, like the Tesla standard one, either require a separate earth stake as an independent CPC reference or an external PEN fault protector.There is no problem at all with carrying out safe EV charger installations. Here's a Youtube channel with many practical examples of installations and the differences and requirements between different manufacturer's chargers...https://www.youtube.com/channel/UCUYJhbsrC1bvVWzgUq83K4A/videosI have avoided drawing undue attention to your new identity (although it was perfectly obvious) because you seemed to be asking rather more sensible questions than you did in either of you 'treez' or 'zenerbjt' personae. However, as you have gone back to talking bollocks for the past couple of days, it doesn't seem to be a secret anymore.I wish you would pick a username and stick to it though!

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 03:53:20 pm
content: Quote from: Ice-Tea on December 13, 2020, 01:48:19 pmWhat you say is basically true. However, an EV charger, or a hot tub, or an exterior power socket for using appliances in the garden are a much greater risk than problems in the house, because of rain.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 03:53:55 pm
content: Quote from: opampsmoker on December 13, 2020, 03:34:25 pmI'd dispute his opinion that a device that senses "real earth" is impractical, and that it would need to have an earth electrode meters away from other services. The impedance of a sensing earth could be tens of K and still work reliably, and it's hard to see how this could be difficult to achieve in most realistic cases.

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 03:57:01 pm
content: John suggests using the reinforcing mesh in concrete as an earth. Does that work? Isn't concrete, even in moist conditions going to have poor conductivity? If its the driveway, and the concrete is only a 15cm thick layer on the surface, isn't even a small amount of dry weather doing to dry it out, and make it a superb insulator?

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 04:02:15 pm
content: Quote from: mikeselectricstuff on December 13, 2020, 03:53:55 pmIsn't his contention that for most people it can be impractical, or at least not reasonably priced, to put that high impedance earth far enough from other services that you can be sure it won't just follow their potential under fault conditions?

author: themadhippy
author_rank: Super Contributor
timestamp: December 13, 2020, 04:32:56 pm
content: so one of the suggestions is a device that monitors the voltage on the earth.im sure we've been there many moons ago, and then the 15th edition appearedQuote:cough: Arc Fault Disconnection Device :cough:

author: Cerebus
author_rank: Super Contributor
timestamp: December 13, 2020, 04:36:24 pm
content: Quote from: coppice on December 13, 2020, 03:57:01 pmThey make much better grounds than one might at first think. Part of this is that concrete never really 'dries out' it might seem dry to the touch on the surface but still contains a lot of water and, more importantly, ionised salts that add to its conductivity. Concrete that truly dries out becomes much weaker, even very friable and crumbly and it's going to take serious long term heating to high temperatures to make it do that. Add a conductive mesh of steel reinforcement, and use the large surface area of that to make your contact spread out across the whole of the concrete and one gets much better results than one might expect from the raw figure that dry concrete (sans reinforcement) has a resistivity in the region of 10-100 k\$\Omega\cdot{cm}\$. Bear in mind that the conductivity of genuine earth relies largely on a thin film of water and dissolved salts coating the individual soil particles.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 04:38:35 pm
content: Quote from: coppice on December 13, 2020, 04:02:15 pmThat would only be an issue with metal pipes, which would surely be long enough that they will always be at "real earth" potential regardless of any local faults ?

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 04:42:18 pm
content: Quote from: themadhippy on December 13, 2020, 04:32:56 pmWell, the experiences with AFCIs in the US has been so stellar, the UK obviously wants to have some too.

author: madires
author_rank: Super Contributor
timestamp: December 13, 2020, 05:27:46 pm
content: Quote from: coppice on December 13, 2020, 03:57:01 pmYes, it works! Over here it's the usual way to build an earthing system for buildings. There are some rules, but it's basically a mesh or ring of steel inside the building's concrete base plate. If you use special waterproof concrete, or protect the base plate with bitumen, or otherwise insulate/isolate it then you have to place a mesh/ring of stainless steel just below the base plate.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 13, 2020, 05:42:30 pm
content: He'd freak out at this electrical systemhttps://en.wikipedia.org/wiki/Single-wire_earth_return

author: bdunham7
author_rank: Super Contributor
timestamp: December 13, 2020, 06:25:38 pm
content: Well after watching most of that I don't see any reason to think that EV charging is particularly problematic, especially in light of the fact that it is already being done without any widespread issues AFAIK. What's next, an expose on why indoor plumbing will never be successful?However, it brings up a few issues. First, I'd like to ask those of you on that side of the pond to never mock or make fun of the American electrical system ever again. Except the wire nuts, feel free to joke about those.The first thing seems to be an issue of all these hazardous potentials that are apparentlyin the ground, just waiting to be exposed by a misplaced earthing rod. Really? I don't know enough about UK regs to comment on the 5 meter distance needed from cables (are they not insulated???), gas pipes andwater pipes(!). How do your earthworms survive? Are the little hedgehogs electrocuted when they burrow? Here in the US, the incoming neutral, ground bus, a grounding rod and the water pipes are all bonded at one point. Gas pipes are often bonded at the end use device, but the incoming gas pipes have an insulated connection to separate the gas distribution system from everything else.The second is the abandonment of the principles of what grounding is for in a low-voltage end distribution system. The two purposes are to carry fault current and to provide equipotential bonding. In damp areas, you can feel a buzz from potentials down to the single-digit volts. If you are wet and well grounded, you might feel it at an even lower voltage. This is why the concrete-mesh is used as a grounding point for swimming pools--this mesh is bonded to every other metal object in the swimming pool domain with a separate ground bonding system, usually unbroken bare copper wire. For this reason, ground conductors never carry any current except in a fault condition. The reason is obvious--you cannot have a current carrying conductor without at least some voltage drop. Combining the neutral and ground like your PEN conductor absolutely guarantees that your 'ground' will not be at 0 volts potential. In addition, of course, it guarantees a grossly unsafe condition should the PEN conductor go open, whereas this doesn't happen in a US system even ifbothneutral and ground are lost, unless there is an additional fault in the system.I'm not sure, even after watching, what this specifically has to do with EV charging. Yes, if your 'ground' actually has a 70V+ potential and you 'ground' your car to it, you may be shocked. How is that different from your water heater? It seems to me that if you allow things like a TN-C-S, you are accepting that your grounds may be 'buzzy' and that if an excavator breaks your PEN conductor (only) you have a severe hazard.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 07:12:20 pm
content: Quote from: bdunham7 on December 13, 2020, 06:25:38 pmThe issue is that inside the house, if the earth is at 100v relative to real earth you won't know about it as all the exposed conductive things are at the same potential.The difference with EV charging is that you can be standing on real earth and touching the house earth.

author: Cerebus
author_rank: Super Contributor
timestamp: December 13, 2020, 07:26:10 pm
content: What's being missed about TN-C-S systems that they are also PME systems - ProtectiveMultipleEarthing. PME systems are grounded in multiple places. The actual probability of losing both the neutral connection to the supplyandthe earth connection is quite low as there is only one neutral connection but multiple earth ones.Moreover, there are strict rules (at least here in the UK) about equipotential bonding of all exposed metalwork inside the served premises. So even if your combined Protective Earth and Neutral goes to a significant potential above the local earth potential, anything you might be in contact with is still at that potential so no shock hazard.

author: bdunham7
author_rank: Super Contributor
timestamp: December 13, 2020, 07:39:38 pm
content: Quote from: mikeselectricstuff on December 13, 2020, 07:12:20 pmHow can your plumbing possibly be at 100V relative to 'real' earth?

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2020, 07:51:36 pm
content: It's highly unlikely the combined protective and neutral conductor would become disconnected on its own, because it's the screen, on a co-axial cable. Even if it does become disconnected, it's also unlikely it will float at a dangerous voltage, because it's a bare conductor buried in the earth and will also be connected to other large metallic objects such as the gas and water mains.Anyway, why have all of these convoluted safety mechanisms? Wouldn't it be much easier to simply mandate that all EV chargers must be double insulated?

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2020, 07:54:29 pm
content: You're about a decade too late to predict that, it has already happened, it's old news. EVs are everywhere, there are several of them on my street alone and I know quite a few people who have them. They're probably not going to completely displace ICE powered cars and they don't have to, the EV is just another tool in the toolbox, used when it fits nicely into the use case.

author: dmills
author_rank: Super Contributor
timestamp: December 13, 2020, 08:03:02 pm
content: So we are really just discussing the standard issues around exporting an earth from an equipotential zone (Which has caused major injuries, there was one in Aus. a few years back discussed hereabouts)?Meh, lots of ways around that pain, and the street furniture guys deal with it all the time.Don't forget that a charger is NOT a plug in device, it is fixed infrastructure so you can provide safety systems that are just hard to do in portable gear.TT is simple if you can pull it off, and we may see the guidance on earthing updated in a way similar to the DNOs notes on earthing radio transmitter sites (Much the same issue).Could a double insulated charging point be practical, a 6kVA iso transformer in a fiberglass box is not that big compared to a car, and effectively no earth on the secondary side, seems sane to me?

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 08:03:57 pm
content: Quote from: Zero999 on December 13, 2020, 07:51:36 pmTerminals corrode. Bad stuff happens. That's life.Quote from: Zero999 on December 13, 2020, 07:51:36 pmThese "chargers" are just protection devices. They simply feed the mains through, detect some fault conditions, and break the circuit when a problem is detected. The cases are usually double insulated, but the feed through to the car, especially in the rain, needs a trustworthy earth for proper protection.

author: bdunham7
author_rank: Super Contributor
timestamp: December 13, 2020, 08:07:52 pm
content: Quote from: Zero999 on December 13, 2020, 07:51:36 pmI don't know the details, but the video seemed to imply that PEN disconnection was at least a remote possibility. I would certainly hope that the design makes it very unlikely given the hazard it would pose. Still, you have the issue that current is flowing in your ground wire, so you can't have perfect equipotential bonding--how imperfect will vary.As for double-insulation, aren't they already? AFAIK, the EVSE ground connection to the car is just provided because there is a default principle of grounding everything. The charging system itself, like the HV battery, is not ground referenced to the car body. At least mine is that way.

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2020, 09:42:42 pm
content: Quote from: coppice on December 13, 2020, 08:03:57 pmAgreed, we just need to reduce the level of risk to an acceptable level. I also don't get why the earth being disconnected is that much more dangerous, for outside, than indoor appliances. If the combined protective earth and neutral were to become disconnected to my house, the kitchen sink would float at a dangerous voltage, so I could get zapped whilst doing the washing up, just the same as I'd be zapped if I was charging an EV with an earthed chassis.QuoteAgain, just make it double insulated, which is trivial with a switched mode power supply, whether it's on the outside, in a house, or in a car. If the car's chassis, never gets connected to protective earth, then it can't happen.

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 09:57:56 pm
content: Quote from: Zero999 on December 13, 2020, 09:42:42 pmThat would mean having a 7kW power supply in the EV box, which would add considerable cost. You've already paid for one of those in the car.

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2020, 10:09:39 pm
content: Quote from: coppice on December 13, 2020, 09:57:56 pmNo, I mean the PSU in the car could easily be double insulated.

author: coppice
author_rank: Super Contributor
timestamp: December 13, 2020, 10:22:43 pm
content: Quote from: Zero999 on December 13, 2020, 10:09:39 pmI assume that is double insulated. The interesting bit is the unisolated 7kW 230V AC power lead out in the rain.

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2020, 10:32:33 pm
content: Quote from: coppice on December 13, 2020, 10:22:43 pmWhat do you mean by unisolated? It should have some means to isolate it, irrespective of whether it's double insulated, or not.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 11:45:50 pm
content: Quote from: bdunham7 on December 13, 2020, 07:39:38 pmBecause it comes in via a plastic pipe, and is bonded to the incoming mains earth or neutral inside the house

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 11:49:58 pm
content: Quote from: Zero999 on December 13, 2020, 10:09:39 pmExcept the standards have already been defined, so it's too late.Also bear in mind the EMC filtering requirements for for a 7, 11 or even 22kW onboard charger. Try meeting EMC on that without an earth to dump the crap into.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2020, 11:53:55 pm
content: Quote from: Zero999 on December 13, 2020, 09:42:42 pmThat's not the case, at least in the UK, where regs dictate that all pipework is bonded to mains earth ( via a 16mm^2 cable I think now). In the case of a PEN fault, your sink would float to mains voltage, but so would everything else in the house so you woudn't get zapped. Not sure how this works with concrete floors though.

author: bdunham7
author_rank: Super Contributor
timestamp: December 14, 2020, 12:09:02 am
content: Quote from: mikeselectricstuff on December 13, 2020, 11:45:50 pmI'd be shocked it that were true.{groan} I'd have to see that to believe it. Even if your water mains are plastic (!?!) water is still conductive. And the drains? The fittings of the drains in the floors? And the scenario you describe would have significant current flowing in places that would be quite hazardous. And as for having your entire house float up to 100V and everyone inside it being safe, I think that's just not reality. Ground is all around you, there's rain, water ingress, whatever. At some point, your house is attached to earth. Suppose you meet someone at your door and you happen to be standing on a metal door sill and he is outside on your walk. If you shake his hand do you both get electrocuted?

author: bdunham7
author_rank: Super Contributor
timestamp: December 14, 2020, 12:17:08 am
content: Quote from: Zero999 on December 13, 2020, 10:32:33 pmIt is ground-referenced voltage, so contact with any part of it will result in a ground fault. These rely heavily on GFI protection in the EVSE. That's true here or there and has nothing to do with if the on-board charger is isolated (it is) or double-insulated (not sure that applies) or ground-referenced (definitely not AFAIK). There used to be non-contact inductive charging systems but they were abandoned early on as expensive and impractical. It was used on the original GM EV1 and the first-gen Toyota RAV4 EV.

author: coppice
author_rank: Super Contributor
timestamp: December 14, 2020, 12:21:50 am
content: Quote from: bdunham7 on December 14, 2020, 12:09:02 amThe waste water and the water in the heating systems are pretty conductive, but I wouldn't rely on the conductivity of the clean water coming in to offer much grounding. We used to rely on the water and gas pipes for earth. They used to offer a good earth, and UK homes were well grounded. Then the water and gas pipes started changing to plastics. The sewer pipes were ceramic, and are now a mix of plastic and ceramic. The earth integrity was destroyed. So, we now have sections in the wiring regulations that require there to be a master earth derived from the incoming power, and all the metal bits in the plumbing system need to be bonded to it by a thick wire (Mike Selectricstuff says its now >=16mm^2).

author: bdunham7
author_rank: Super Contributor
timestamp: December 14, 2020, 12:34:27 am
content: Quote from: coppice on December 14, 2020, 12:21:50 amI'm sure that's all true, but I'm not believing that a ragtag assorted collection of grounded bits will reliably all float up together if the mains-derived master earth floats up above actual earth. Imagine your plumbing is all at 100V above 'real' earth and you are in a ground-floor shower with a concrete floor and buried metal drains. There were a few American servicemen killed in Iraq (electrocuted in the shower) by some foolishness just like that. I think instead that if you have an open like that, there will be a fairly high fault current before anything starts to float up. If that fault current is not enough to stop the whole system from floating up to 100V, I think that there is then a severe hazard, not a happy isolated floating household.

author: james_s
author_rank: Super Contributor
timestamp: December 14, 2020, 06:14:00 am
content: Quote from: mikeselectricstuff on December 13, 2020, 11:45:50 pmThis just came up with a UK friend the other day when I mentioned something about the ground rod next to my house. Apparently you don't use those there? Here every house has to have a ground rod driven into the earth that is bonded directly to the ground bus in the panel by 8AWG copper wire. Specific requirements vary by locality but the last time I did a panel upgrade code had been updated and it was required to install a minimum of two ground rods at least 6 feet long placed a minimum of 6 feet apart driven into the earth and bonded to the panel by a continuous wire, no splices allowed. The plumbing if metal must be bonded to the same ground bus in the panel, at a location no more than 3 feet from where the pipe enters the structure, also with #8 copper. The center tap of the distribution transformer out at the street is also earth bonded at that location and the neutral wire runs from that point through the meter base and into the neutral bus in the panel which itself is also bonded to the ground bus. It's almost unheard of to encounter a fault with the earth ground although I've heard of it happening in very rare instances with homes old enough to have not been built with grounded wiring but I've never seen it.

author: Zero999
author_rank: Super Contributor
timestamp: December 14, 2020, 09:16:09 am
content: Quote from: mikeselectricstuff on December 13, 2020, 11:53:55 pmThat was my point and what about outside lights, feeds to outbuildings and outdoor appliances? How are EVs a special case?Quote from: coppice on December 14, 2020, 12:21:50 amHave there been any instances of anyone being killed or seriously injured as a result of a break in the combined earth-neutral contuctor? If so, blame the gas/water/electricity companies for messing up!Quote from: bdunham7 on December 14, 2020, 12:34:27 amAre you sure it wasn't because they used one of those dodgy showers discussed in the following thread?https://www.eevblog.com/forum/projects/suicide-shower-hear-teardown/

author: Siwastaja
author_rank: Super Contributor
timestamp: December 14, 2020, 04:31:40 pm
content: Dying from electrocution isextremelyrare in everything except the absolute worst offender countries.For example in Finland (population 5M), just some 40-50 years ago there were approx. 20 fatalities from electric shock per year, nobody considered this a problem as number of fatalities from traffic accidents was 30-40 times more. Yet, during a decade (after mid-1980's), this number dropped to approx.zero point five, i.e., a 40x reduction while the traffic accident fatalities went down just by some 2x during the same time.I'm sure the numbers are similar everywhere. This happens because making electricity safe is quite easy and not too expensive!Electricity is damn safe. It was quite safe even with the totally crappy electric culture decades ago, compared to anything else (safety culture was not considered that big of a deal regarding anything else, either). Now it's so safe dying from electrocution is similar to getting abducted by UFOs, in the sense of almost nobody knows no one who knows anyone who knows anyone who have died of electric shock.Another thing where people misunderstand the scales is the power an energy requirements of EVs, the common misconception is that electrifying the traffic means massive increase (like many times) of the electric energy and peak power consumption. But pretty much our infrastructure already runs on electricity, typical home wiring varies from 20 kW to maybe 100kW depending on place. 10kW stove is normal, direct electric heating easily pulls another 10kW, there is absolutely no problem with any of this, the system has worked at these power levels over half a century. Now overnight EV charging (we were discussing about homes, after all) works good enough with some 3kW, maybe you want to have 10kW but that's not a hard necessity. Most of this overnight charging happens, surprise surprise, during night time when consumption is already below average (and utility companies have traditionally tried to encourage heating by reduced night time tariffs to even out the consumption). There's nothing special about this power level what comes to house wiring.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: December 14, 2020, 05:34:21 pm
content: Hydrogen is the future.And you hear noone about electric-cars have more fine-dust because the higher weight on the tires.

author: james_s
author_rank: Super Contributor
timestamp: December 14, 2020, 05:38:11 pm
content: Huh? Is that sarcasm? Hydrogen is dead, it was a stopgap until battery tech improved sufficiently and that ship has sailed. In the US I think you can still buy hydrogen in a few places in one state but it never went anywhere wider. Millions of electric vehicles are on the road, spread across all 50 states.

author: themadhippy
author_rank: Super Contributor
timestamp: December 14, 2020, 05:49:22 pm
content: QuoteIn the uk we do,properly known as a TT system,(tera tera or earthed earth) its just not very common any more

author: Monkeh
author_rank: Super Contributor
timestamp: December 14, 2020, 05:58:44 pm
content: Quote from: mikeselectricstuff on December 13, 2020, 11:53:55 pmThere is no need to bond if the pipework does not introduce a potential (ie. plastic supply or an insulator fitted), and it's 10mm² for typical PME supplies and 6mm² minimum for others (and one half of the required earthing conductor size.. which in practical terms again is probably only 6mm² with calculation..).

author: David Hess
author_rank: Super Contributor
timestamp: December 14, 2020, 09:50:09 pm
content: The loss of neutral without a separate Earth ground is hazardous however why is this different with an electric vehicle charger instead of any other large load like air conditioning or electric heating?A ground fault interrupter for such a heavy load might not save someone if they are exposed at the time that a fault occurs but that is a tiny opportunity.In the US, neutral is bonded to Earth ground at the service entrance and such a large load would not be connected to neutral anyway, or draw much from neutral, because we use split phase.

author: dmills
author_rank: Super Contributor
timestamp: December 14, 2020, 10:41:46 pm
content: In terms of lost neutral causing a (near) electrocution I give you a 2018 incident in Australia which I think was discussed here somewhat extensively.https://www.abc.net.au/news/2018-03-06/denishar-woods-suffered-brain-damage-from-tap-electric-shock/952001411 year old girl, out watering the lawn tried to turn the tap off after the power went out, as far as I can tell, tap was on metal pipe bonded to MET and hence the system neutral. Neutral seems to have failed upstream, leaving the return path to the transformer involving the tap and a child with bare feet on wet ground, it clearly did not end at all well.This is why exporting 'earth' from an equipotential zone is looked at askance (See also the 'special locations' guidance for stables, turns out that 4 legs worse when it comes to potential gradients in the ground).An aircon plant or electric heater is generally inside the equipotential zone, it might be way above ground voltage wise during a fault, but is so is everything else you might touch that is a non issue, difficult to make that stick outdoors with mobile gear, which is why the garden tools are all double insulated with 2 core cables.TT is the simple answer if you are in a position to do so, or TN-S, if it really is TN-S (Often when the street feeder cable is upgraded you wind up with TN-C-S without realising it).

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 15, 2020, 12:24:55 pm
content: QuoteThanks DMills, Absolutely. Tragic for the 11 year old girl in your post #48. JW is right.As you know, TT isnt seen anywhere these days...and as you imply, TN-S ends up being TN-C-S.JW has called it!He's right, EV's are on very dodgy ground.Here is a terrible tragedy caused by loss of neutral, what JW was referring to........https://www.youtube.com/results?search_query=horses+electrocuted+at+newbury+...Still wanting electric vehicles?Thanks @David Hess (post #47) you seem to have a different situation in some parts of USA... "split phase", so that i believe is a safe situation for EVsThanks also to BDnham7 in post #39 for pointing out the terrible tragedy of the American Servicemen who also tragically succumbed to this electric fault situation.Thanks @ MikesElectricStuff From post #20, good point..-->QuoteThanks DMills (post #25)...maybe this is the answer..but heavy-->QuoteThanks MikesElectricStuff (post #34)..-->QuoteThanks from BDunham7 in post #19...-->Quote...From this i take it you are endorsing the video of the top post(? rhetorical)

author: Gyro
author_rank: Super Contributor
timestamp: December 15, 2020, 12:31:09 pm
content: Quote from: opampsmoker on December 15, 2020, 12:24:55 pmSadly, water taps and racecourse fixed installations don't have PEN fault protection. Decent EV charger installations do.Are you saying that outside taps and racecourses cannot happen?

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 15, 2020, 01:05:38 pm
content: Thanks, in video of top post, JW goes through all protections, but reveals why all are not sufficient.

author: Cerebus
author_rank: Super Contributor
timestamp: December 15, 2020, 01:05:58 pm
content: Quote from: opampsmoker on December 15, 2020, 12:24:55 pmOne swallow does not a summer make. The plural of anecdote is not evidence.Two solitary examples from a world's worth of EEs and hobbyists is not enough evidence to make your case. I counter with the millions of examples ofallthe EV charger owners and users in the world who are still alive - in 2018 alone there were 1.6 million EV chargers installed worldwide*, 90% for private use.BTW, I've got an investment opportunity coming up related to the sale of Tower Bridge, would you be interested?*Source:https://www.mordorintelligence.com/industry-reports/electric-vehicles-charging-stations-market

author: themadhippy
author_rank: Super Contributor
timestamp: December 15, 2020, 01:21:07 pm
content: QuoteAbsolute rubbish,not as common as they were as an incoming arrangement but theres still plenty of it about.

author: Cerebus
author_rank: Super Contributor
timestamp: December 15, 2020, 02:13:00 pm
content: As I understand it TT supplies are very common in isolated rural areas (so think "a farm miles from anyone else" with the neutral coming in on poles, so there's a high risk of losing it), and in industries that can present a balanced 3 phase load to the incoming supply (which may be medium voltage).

author: madires
author_rank: Super Contributor
timestamp: December 15, 2020, 02:56:37 pm
content: Quote from: opampsmoker on December 15, 2020, 01:05:38 pmSo better stay inside. If you step outside the remains of a de-orbiting satellite could hit you. It's about how large or small the possibility of an incident is. You can add more protection measures to increase the reliability, but it will become also more expensive while you aren't able to achieve 100% safety.

author: dmills
author_rank: Super Contributor
timestamp: December 15, 2020, 04:00:26 pm
content: Yea, you can find examples of almost any low probability event if you there are enough opportunities for it to occur and you look long enough.Thinking about it, the cure is actually really quite simple, you just fit a three phase RCD (GFCI, same thing), with phase, neutral AND earth being the three monitored conductors.This will trip is there is any meaningful current in the earth conductor that does NOT return by one of the live conductors, so really needs a second 2 pole RCD to provide that protection, but hardly a big deal. No need for reference electrodes or anything like that, you just trip ALLL THREE conductors open on seeing net current not summing to zero. I would bet that at least some of those protective devices work this way, and it is very well tried and tested technology.The only weird thing about it is having a breaker that trips the earth circuit open as well as phase and neutral, but that is rather the point.

author: Cerebus
author_rank: Super Contributor
timestamp: December 15, 2020, 04:53:16 pm
content: Quote from: dmills on December 15, 2020, 04:00:26 pmThat is the sort of thing that can result in one wasting days and days explaining it to a well-meaning, over-eager, but under-knowledgable, safety officer.

author: dmills
author_rank: Super Contributor
timestamp: December 15, 2020, 05:01:01 pm
content: Been there, got frustrated, was wise enough to hide the body.'Elf and safety types have their value, but when they ask a subject matter expert about something that looks a bit off (And I never mind being asked, I am as prone to mistakes as anyone else), and get the response of 'Yes, I know, it is correct in this context', they do need to know to back off.Regards, Dan.

author: Zero999
author_rank: Super Contributor
timestamp: December 15, 2020, 08:54:14 pm
content: Quote from: dmills on December 15, 2020, 04:00:26 pmThat's a good idea. The only thing which makes me slightly wary is it might not disconnect the conductors in the safest order, but I suppose you've got the standard two pole RCD for that. Whether it's safe, or a good idea, or not, doesn't matter though. It has to comply with the regulations and if it's not in the rule book, you might have difficulty getting such an installation approved and have problems with insurance.The regulations themselves can be quite dumb. My parents have a heater in their bathroom. It was originally next to the shower, but some box ticker electrician decided to move it next to the airing cupboard, because it was slightly too near the shower to comply with the regulations. The problem is, it now means the airing cupboard door opens in front of the heater, creating a fire hazard. There's now a big scorch mark on the door, when it was opened, whilst the heater was on. It was much safer in its original position. There was no shock hazard, because it was behind the shower screen. When this COVID stuff is over, I might move it back, or install a switch on the cupboard door, whichever is easier.Quote from: dmills on December 14, 2020, 10:41:46 pmQuote from: opampsmoker on December 15, 2020, 01:05:38 pmI have watched the whole video. I can see how bad things can happen, as a result of the combined earth & neutral failing, but they're not unique to electric vehicles, as evidenced by the outside tap incident, quoted above.

author: themadhippy
author_rank: Super Contributor
timestamp: December 15, 2020, 09:18:35 pm
content: QuoteIts not the regs that are dumb,if the box ticker had bothered to read and understand the regs instead of doing a 1 day power point regs course they might noticed the bit in section 4 that says you cant use electrical equipment to burn the house down

author: Cerebus
author_rank: Super Contributor
timestamp: December 15, 2020, 09:54:13 pm
content: Quote from: Zero999 on December 15, 2020, 08:54:14 pmThe problem here is the presence of the word "Regulations" in the IEE/IET Wiring Regulations. They aren't regulations, they are guidelines. The preface of every version of "The Wiring Regulations" (also known as BS 7671) has included a foreword by the HSE something like this:QuoteNote the bold part [my emphasis]. Conformity to BS7671 islikelyto mean that one will conform to theactualelectrical safety regulations as laid down on law. Note also that conformity to BS7671 is noguaranteethat one will conform with the actual regulations.Slavish adherence to "The Wiring Regulations" is no guarantee of conformance with the law. Similarly departing from "The Wiring Regulations" does not automatically mean that an installation is non-conforming with the actual regulations in law; the actual regulations require that the work is designed and executed competently and safely and if that is achieved while "breaking" rules in the IET/IEE book that's fine.

author: msat
author_rank: Regular Contributor
timestamp: December 16, 2020, 12:01:54 am
content: There's a much higher chance of having an EV's battery experience a thermal runaway event and burning down the house than there is of getting electrocuted by the charging system. Nevermind the even higher chance getting in a fatal car accident. Almost everything carries some element of danger. If the safety of a charging system was legitimately the biggest concern regarding EV use, then we'd be quite fortunate indeed.

author: Zero999
author_rank: Super Contributor
timestamp: December 16, 2020, 08:49:10 am
content: Quote from: Cerebus on December 15, 2020, 09:54:13 pmYes you're right. I did the course, but it was a long time ago and that's one of the things they mentioned. Perhaps they should change the name of the book, to stop people from taking it as law.Quote from: themadhippy on December 15, 2020, 09:18:35 pmYes, had it been my house, I would have been furious. Unfortunately, I wasn't around at the time to give the electrican an ear full!

author: opampsmoker
author_rank: Regular Contributor
timestamp: December 16, 2020, 08:52:43 pm
content: Quote..OK Thanks to DMills, this sounds to be the best solution so far...but as discussed later, would maybe need the regs to be changed...or re-written to allow junior electricians to get their heads round it.I dont think electrified equipment outside of the house is that common at the moment...EV's arent even that common, so i can see why JW has flagged this problem up, its a big change that pushes on the regs like nothing else ever has of late. Those horses getting tragically electrocuted in the video of post #49 shows how significant potential gradients can easily exist in earth...over the small distance between their hooves.

author: Cerebus
author_rank: Super Contributor
timestamp: December 16, 2020, 09:19:28 pm
content: Quote from: opampsmoker on December 16, 2020, 08:52:43 pmIn the face of the huge number of street lights in the world I don't how you, of all people, can say that.(For those not in the know, the OP has asked for lots of help on here on the design of PSUs for ... street lighting.)

author: dmills
author_rank: Super Contributor
timestamp: December 16, 2020, 10:53:08 pm
content: To be fair, streetlighting supplies are a bit weird.Thinking about it I would probably put a deliberate impedance in that external 'earth' line to prevent trips due to small IR voltages developed in the PEN in the ordinary course of business. 500r would fire a 20mA trip at 10V, a 30mA one at 15V and would limit the 'earth' current to a reasonable couple of hundred mA (Which is acceptable, because RCD), alternately a couple of really butch back to back diodes, but I dislike semiconductor junctions in this application that is Safety Critical in a situation that is difficult to monitor), you could even do both, which is possibly the best option, resistor to limit earth line current to something the diodes will laugh at, diodes to stop spurious tripping from IR drop in the PEN, touch voltage handled by <0.5s disconnect time of the RCDs.I would be shocked if the PEN protection devices did not work on substantially this principle, but probably combining both differential trips into a single device (Cheaper to manufacture that way, only one trip solenoid), it is simple, obvious and as close to foolproof as anything dealing with 32A 240V can be.

author: Ice-Tea
author_rank: Super Contributor
timestamp: December 17, 2020, 09:24:30 am
content: Quote from: opampsmoker on December 16, 2020, 08:52:43 pmCurrently outside my house:- 2 LED lights at the front of my house- 3 CCFL lights at the rear- Dual IP mains outlet at the rear of the house- 3 sockets around the garden house- 4 LEDs at the patio- Pool pump- Pool dosage machingBut sure.

author: madires
author_rank: Super Contributor
timestamp: December 17, 2020, 10:32:59 am
content: Quote from: opampsmoker on December 16, 2020, 08:52:43 pmIt's common, especially at this moment. It's called Christmas lighting, and you'll find plenty of it in front yards.

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2020, 02:00:29 pm
content: Quote from: madires on December 17, 2020, 10:32:59 amMaybe he takes his lawn inside to mow it, and his hedges inside to trim them.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: December 17, 2020, 02:05:30 pm
content: Quote from: james_s on December 14, 2020, 05:38:11 pmMaybe someone is making more money that way.Unless there is some new revolutionary accu technology this wont work.They want to charge faster, then you need a heavyer accu, and is more dangerous with more power.They say 10 years ago "this will revolutionize accus", still waiting.They all dont care about the envoirment, they all need to do something, and the opposite might happen.

author: ejeffrey
author_rank: Super Contributor
timestamp: December 17, 2020, 05:27:30 pm
content: Quote from: Cerebus on December 15, 2020, 04:53:16 pmThe point isn't that everyone should go out and wire EVs like this. It is that if this were a major problem regulations could be updated to allow or require that type of installation for EVs.

author: james_s
author_rank: Super Contributor
timestamp: December 17, 2020, 05:48:44 pm
content: Quote from: coppice on December 17, 2020, 02:00:29 pmMains powered electric lawnmowers are rare in the US, I think I've seen 2 or 3 of them in my life. 4 stroke air cooled gasoline is the norm, now cordless electric is gaining popularity. Electric hedge trimmers are somewhat more common but in this region at least maybe 1 in 50 houses has a hedge.

author: Cerebus
author_rank: Super Contributor
timestamp: December 17, 2020, 05:50:03 pm
content: Quote from: ejeffrey on December 17, 2020, 05:27:30 pmErm , that's a bit of anon-sequitur.

author: james_s
author_rank: Super Contributor
timestamp: December 17, 2020, 05:53:48 pm
content: Quote from: Jan Audio on December 17, 2020, 02:05:30 pmCharge time doesn't matter, every one of the numerous EV owners I know plug their car in when they get home and its fully charged every morning. Hydrogen doesn't give you that advantage, you still have to go out somewhere to get fuel, fuel that is much more difficult to handle and store than gasoline, and the infrastructure has not come anywhere close to critical mass. Additionally hydrogen is not even really a fuel, you can't mine it, you have to use electricity (or crack hydrocarbons) to produce it which is itself an inefficient process. Hydrogen is dead, it's a complete non-starter, it died on the vine a decade ago.

author: dmills
author_rank: Super Contributor
timestamp: December 17, 2020, 06:38:10 pm
content: More then that, I (briefly) worked on a Ford/GM collaboration on hydrogen fuel cell vehicles back in the day (Around Y2k), and the joke in the office then was that we were doing this because spending a billion dollars on alternative fuels research was cheaper then finding a Californian senator that would reliably stay bought.Some of the spin off technology has become mainstream in automotive however, code generation from simulink models, things of that sort.Hydrogen is a purely crap transport fuel (Unless you are doing rocket upper stages and need ultimate Isp with an unlimited government budget, and even then....). Even if you slush it, it is just not very dense, so your tanks for a reasonable range end up fucking massive, and having the public handle cryo hydrogen? Really!??If you do the gas thing then you need big tanks at really serious pressures, there is a word for that in a suitable crash situation....Then of course the cheap way to make the stuff is to steam reform a hydrocarbon which has CO2 as a biproduct.The upside, such as it is was that you can sidestep the Carnot limit, but you could do that with a fuel cell power station and if it does not work economically there it is surely no better at small scale!

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2020, 06:56:38 pm
content: Quote from: james_s on December 17, 2020, 05:53:48 pmThere is a huge selection bias there. The people who have issues with the range of EVs, because they do numerous long journeys, are not currently buying EVs. If you just do a modest commute each day, and some driving around town, most EVs have few serious drawbacks.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 18, 2020, 01:14:54 am
content: I worked in the battery project that was GM, Ford, and Chrysler with the US Govt. back in the 80sCharging is not the problem. Lots of different solutions.The problem is the batteries themselves, although there are better batteries now.The other bigger problem is where to get the electricity to charge with.We do not have enough generating plants.Efficiency is also a problem, line losses (and charging losses)would mean burning more fuel than a car would for the equal amount of miles.Over one hundred years ago, there were workable electric cars and delivery trucks in Detroit, my hometown. Some of the old mansions had big transformer charging stations in their garages and the downtown businesses had special parking for these vehicles with charging stations also.All this without any government incentives.It has been done, although these old vehicles would have limited use in today's driving world.I do not know if this is relevant but some downtown areas in major cities were supplied with Edison DC electricity until Tesla came along with AC.

author: Zero999
author_rank: Super Contributor
timestamp: December 18, 2020, 09:48:35 am
content: Quote from: Wallace Gasiewicz on December 18, 2020, 01:14:54 amYes, disitribution is also a big problem. In the UK the government wants everyone to phase out petrol cars and get everyone to heat their homes with electricity, using heat pumps, rather than natural gas. The problem is at the moment, the distribution system is no where near up to it. Having lots of smaller generators, such as homes with solar panels will help to some extent, but the problem with that is no one will be at home to charge their car, when they're producing solar power.QuoteCan you post any calculations to support that? I doubt it. Modern batteries are very efficient and an oil fired power station can operate close to its peak efficiency most of the time, whilst the internal combustion engine inside a car rarely does. Electric cars can also use wind, solar, hydroelectric and neuclear power.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 18, 2020, 12:13:44 pm
content: The longer the distribution line the more the loss. I am nowhere near an expert.Line losses are between 10-20% depending on how far you are from the generator.There are more losses in converting high volts to lower volts.Then in some circumstances there is loss converting DC high power lines to AC..volts. (not common)Then there is the energy spent in making the lines and transformers.Having said that, I think the big generating plants are much more efficient than your standard good Honda generator.Steam power plants are perhaps 40% efficient while your little Gasoline Honda is perhaps 20%.Your car is perhaps 20-35% efficient in converting gasoline to motion.Lets be generous and say the power plant is 50% efficient.Line losses are 10%, down to 45% efficient.Charging loss 10% down to 41% efficient.DC Electric motors are much more efficient than gasoline engines, but still 80% efficient is really good, so another 20% loss, down to about 33% total efficiency.Loss of power in other mechanical parts, electric power transfer systems etc, maybe 80% efficient, another 20% loss, down to 26% efficiency. In the range of a regular gasoline car.Now there are also power losses in transmission of your gasoline, a truck has to bring it to the gasoline station, and an electric motor has to pump it, for example.This is just a gross estimation based on what little knowledge I can fit into my remaining working neurons.Kind of difficult to get exact numbers, and I do not do this for a a living. Interesting to talk about though.There are also "one time" energy costs to be dealt with, like energy needed to make aluminum for gasoline engine blocks and energy needed for making transmission lines and towers etc....Notice I am ignoring the few places on earth that can use "free" energy, like hydro plants. Aluminum smelting takes a lot of electric energy and if you do a bit of looking around, you can see that aluminum and alumina plants are generally near hydro power plants.Canada, for example, uses lots of hydro. Tesla's Niagara Power plant was a marvel.The problem I see in "alternate electric generation" like solar and wind, is not just the unpredictability. It is the energy cost of making the solar panels and turbines. Then the maintenance of these things, including the disposal in some cases of relatively toxic stuff. I really have not figured out the energy costs in making solar and wind generators. Lots of steel in those wind turbine towers, and a lot of coal used to make the steel.

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 12:32:44 pm
content: Could wepleasenot let this deteriorate into yet another "hydrogen versus electricity versus liquid fuels for vehicles" thread as that has beenwell and truly done to death over and over again on this forum? Please folks, can we keep it relevant to the thread topic?

author: Monkeh
author_rank: Super Contributor
timestamp: December 18, 2020, 12:36:28 pm
content: Quote from: Cerebus on December 18, 2020, 12:32:44 pmWhat is the thread topic, again? "Earthing confuses me and I draw extreme conclusions"?

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 01:55:04 pm
content: Quote from: Monkeh on December 18, 2020, 12:36:28 pmSomething like that.At least the digression into "how to safely earth things" was (1) on topic, (2) reasonably novel. There is a limit to how many times a topic loosely connected with electric vehicles needs to do the whole "alternative vehicle energy sources" debate again. It ends up being the exact same people, trotting out the exact same arguments for the \$n\$th time. How it still keeps their attention I don't know.

author: Zero999
author_rank: Super Contributor
timestamp: December 18, 2020, 05:34:00 pm
content: Wallace Gasiewiczcheck your figures again. ICU enginess are much less efficient than that and can't do regenerative braking: a big advantage of EVs.Quote from: Cerebus on December 18, 2020, 01:55:04 pmNot me. I've hardly participated in this discussion, apart from the odd post, here and there. I tend to not bother clicking on threads which are more than around 10 pages long, unless I was involved at the start.To summarise electric cars have advantages and disadvantages. They're great for the daily commute, providing it's within the car's range, which is limited, compared to ICU cars and take a long time to charge, so no good for long journies. They now use less energy, than ICU cars and are much cheaper to run, but the batteries are expensive. At the moment the electrical distribution/generation system can't handle everyone having an electric car. In future battery technology will hopefully improve, along with the electricity generation & distribution infrastructure.

author: Gyro
author_rank: Super Contributor
timestamp: December 18, 2020, 06:59:12 pm
content: Quote from: Monkeh on December 18, 2020, 12:36:28 pmI'd be happy if somebody could just persuade @treez to change the stupid thread title. Historically, that doesn't seem likely though.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 18, 2020, 07:08:35 pm
content: Quote from: Zero999 on December 18, 2020, 05:34:00 pmNo but it doesn't need to, because it will be decades before everyone has an electric car.According to the National Grid, if everyone went EV today they'd only need 10% more capacity :https://www.nationalgrid.com/stories/journey-to-net-zero/5-myths-about-electric-vehicles-bustedMost EV users will charge overnight, when demand is low, so peak demand isn't going to increase much, if at all.Most people only use a small proportion of their battery capacity each day. Load management will be able to smooth out the load, and things like V2G mean that EVs will potentially be actively helpful in balancing the grid.Obviously there will be some places where local upgrades are needed, but seems like overall grid capacity isn't going to be an issue any time soon, and there is plenty of time to build out capacity as needed.

author: james_s
author_rank: Super Contributor
timestamp: December 18, 2020, 07:33:33 pm
content: Quote from: coppice on December 17, 2020, 06:56:38 pmIMHO people who need long range and/or rapid refilling should stick with ICE or hybrids for the foreseeable future. EVs are ideally suited as commuter/town cars, a use case that covers a huge majority of the driving that takes place. They're not for everybody but they are well suited to vast numbers of people. Almost everyone I know who has one lives in a multiple car household, using the EV for the majority of the running around and a conventional car for anything else.

author: james_s
author_rank: Super Contributor
timestamp: December 18, 2020, 07:37:40 pm
content: Quote from: Cerebus on December 18, 2020, 12:32:44 pmWhat more is there to discuss on the original topic?

author: Cerebus
author_rank: Super Contributor
timestamp: December 18, 2020, 09:14:48 pm
content: Quote from: james_s on December 18, 2020, 07:37:40 pmProbably nothing, but that doesn't mean it's time for yet another rehash of the same points about EVs that have been done to death in every thread that even mentions EVs. Looks like it's time for me to to hit 'ignore topic'.

author: Zero999
author_rank: Super Contributor
timestamp: December 18, 2020, 09:36:19 pm
content: Quote from: mikeselectricstuff on December 18, 2020, 07:08:35 pmI give you that: there's plenty of time for the infrastructure to improve.QuoteThat's fine at the moment, but what about in the future, when we have more solar power and fewer fossil fuel plants? There will be a surplus, when everyone is out and about and not charging their cars.The National Grid will need to invest a heck of a lot in energy storage for this to work smoothly.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 18, 2020, 10:58:54 pm
content: Quote from: Zero999 on December 18, 2020, 09:36:19 pmIn Q2 of 2020, wind generated about 3x as much as solar.https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/920621/Renewables_September_2020.pdfAnd it's not like batteries are getting cheaper or anything....

author: james_s
author_rank: Super Contributor
timestamp: December 19, 2020, 02:01:44 am
content: I don't think batteries will ever compete with liquid fuels in terms of energy density or speed of refilling. It will require behavioral adjustments, EVs offer some conveniences in exchange for some aspects that are less convenient. Petroleum fuels are not going to disappear in the foreseeable future, then there are other liquid fuel options, alcohols and bio-based oils that can fill some of the gap. Perhaps we can come up with ways of manufacturing synthetic liquid fuels in sufficient scale, I mean hydrogen also has to be manufactured, you can't mine it anywhere. If even half the people who are in an ideal situation for an EV to meet their needs switch to them that would buy us a lot of time. While growing rapidly I'd guess that alternative fuel vehicles including EVs and all others combined are not even at 1% market saturation when considering people for whom they would be well suited. There is a LONG way to go before we have to worry about the edge cases and find ways to shoehorn them into applications requiring long range and rapid charging. Hydrogen is still dead any way you look at it, it just has too many disadvantages to ever be a practical automotive fuel.

author: Zero999
author_rank: Super Contributor
timestamp: December 19, 2020, 11:06:45 am
content: Quote from: mikeselectricstuff on December 18, 2020, 10:58:54 pmIt can't cover everything. Quite often, during in the winter we get cold and very calm weather, with lots of high pressure, such as a couple of weeks ago, when much of the country was blanketed in fog. We need an energy source which can tide us over such periods and batteries can't store that much energy.Quote from: james_s on December 19, 2020, 02:01:44 amYes, I think synthetic fuels are a good idea, but not necessarily for road use, but as a means to dump excess energy, when there's a surplus, so it can be used to generate electricity, when there's no sun and wind.

author: richard.cs
author_rank: Super Contributor
timestamp: December 19, 2020, 12:17:14 pm
content: Quote from: bdunham7 on December 13, 2020, 06:25:38 pmAgreed.Quote from: bdunham7 on December 13, 2020, 06:25:38 pmBut it's so much fun.Quote from: bdunham7 on December 13, 2020, 06:25:38 pmThe vast majority of the time low voltages exist between different bits of metal stuck in the ground. All this 5 metre stuff is people getting terribly worried about the broken neutral case which is very rare. Rare in the sense that most installations will never experience it, on a national level it seems to happen a few times a week or something like that.The US setup generally has more than one such point - doesn't any customer sharing a transformer with other customers effectively have several because they also have their neighbours N-E connections? And I thought you connected LV neutral on the transformers to HV neutral (we don't have that - all our HV is delta) too?Quote from: bdunham7 on December 13, 2020, 06:25:38 pmI am not a great fan of TNC-S but generally it works OK in practice.Within a customer installationthere is always full separation of neutral and earth, externally one possible setup is TNC-S in which case two things are done in the UK, the first is to make the probability of an open-circuit neutral vanishingly rare (concentric conductors, double crimps, etc.), and the second is to mitigate the risk when it occurs by a mixture of lots of supplier-side earthing rods along the neutral and equipotential bonding within the customer installation.It's all about a trade-off of the different types of faults and their likelihood of detection. Historically we had lots of TN-S with separate earth and neutral conductors all the way to the substation. A major issue with this turned out to be that because no current flows in the earth except under fault conditions, people generally didn't notice open-circuit earth connections. In some cases a broken supplier-side earth conductor could go unnoticed for years. We have a lot of TT systems (neutral earthed at substation, earth rod with no neutral connection at customers), but they are critically dependent on RCDs (GFCIs), whose reliability turns out to be a bit pants. We do have a few installations we call PNB, which is essentially like the US system with only one customer per transformer, and it behaves generally like TN-S. One of the key properties of TNC-S is that the fault condition is higher probability of harm, but of short duration (hours) because an open neutral is obvious and recognised to be dangerous.All kinds of exciting faults can raise the ground voltage in a US system. I personally don't like the lack of separation between HV and LV, but consider this one for example. An open neutral upstream of the E-N bond in your panel, when you share a transformer with a neighbour with a swimming pool. Your load current returns through your installation neutral, through your ground rod, back up your neighbours ground system, and via his neutral back to the transformer. Since he has a huge amount of earth contact from his swimming pool and you just have a rod, nearly all the voltage drop occurs your side so you see nearly the full line voltage on your ground.Quote from: bdunham7 on December 13, 2020, 06:25:38 pmIt's not, EVs are just an unusually large surface area metal object, connected to the electrical system earth, which is generally parked outside of the equipotential zone. Outdoor electrical appliances here are generally all double-insulated.Personally I think the system could stand a considerable amount of improvement. For a start the UK practice of giving people large single-phase supplies is pretty crap and a German style modest-current 3-phase supply would be better, giving better system balance / lower neutral currents. Secondly though, something like an impedance-earthed distribution transformer would be rather nice. Distribute the earth like TN-S, but put a deliberate 0.1-1 Ohm in the transformer star point. L-E short current is then limited to a thousand amps or so (with TNC-S it can be up to around 20 kA in the UK) which is plenty for tripping smallish RCDs, and also allows simple, robust earth-fault-detection devices that are nowhere near as unreliable as RCDs. There are some other advantages: 1. Because the earth fault current is limited the distributed earth conductor can be modestly sized and cheap, so there's not huge amounts of copper sitting in the ground and never used, 2. During a L-E fault most of the voltage drop occurs in the substation resistor, there's minimal rise of earth potential anywhere in the system during the fault. Faults then only need to be cleared in a short enough time to avoid fire rather than shock. This is similar to how we do HV distribution in the UK.

author: bdunham7
author_rank: Super Contributor
timestamp: December 19, 2020, 05:06:28 pm
content: Quote from: richard.cs on December 19, 2020, 12:17:14 pmInstallations vary, but for above-ground (poles) that I've seen, the HV is either not grounded (two-insulator transformer) or is ground-referenced, but not connected directly to the LV side.QuoteDisconnection of the neutral before the entrance ground would be a very bad thing, but most installations are such that losing only the neutral is physically very unlikely even in a storm or an accident. With split-phase, if there are no other ground points, then you would not have ground fault current but you would have a voltage imbalance on the 120V circuits. The 240 circuits would be unaffected, at least in theory. In the case of shared transformers with only one house losing the neutral, then you have what you described--current through the earth to your neigbors. However, the current would only be the difference between the current in the two 120V phases. Installations will vary, but in my case the transformer is shared with 4 neighbors and we all have swimming pools, as well as metal plumbing that is buried an d connected to the common city water mains. I don't know what sort of fault current that would support, but I'm guessing it would take quite a few amperes to raise the ground potential up to a hazardous level. Even with all of that, losing a neutral is regarded as a serious hazard that should be a very rare occurrence--much worse than losing a phase, which itself is pretty bad if you aren't prepared for it.

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2020, 06:30:31 pm
content: I've never heard of the ground voltage becoming raised in the US, maybe it's happened somewhere but if it has it's one of those things that is up there with being struck by lightning or killed by a piece falling off of an airliner passing over, these things have happened but they are so rare that most people don't spend much time worrying about it. Due to the requirement of neutral and metal plumbing being bonded to ground at the panel which is directly connected to one or more grounding rods driven into the earth at the service entrance of every structure and the neutral at the transformer being itself bonded to ground it's extremely difficult to have a situation where the building's ground system is floating above the potential of the earth which is exactly the point of having a grounding system. The requirements are pretty stringent, the grounding system has to be bonded with #8 copper wire which is pretty heavy stuff, and it has to be a continuous run from the ground bus in the panel to the ground rod(s) driven into the earth, you cannot have any splices that could potentially fail. The plumbing has to be bonded in a similar manner, clamp within some short distance of the water main entering the building, continuous run of #8 copper back to the grounding bus in the panel.Losing the neutral is a little more common, still rare but I've seen that happen. All it takes is a bad connection at either the transformer or in the incoming neutral panel and then the voltages on the two legs of the drift around relative to each other but absolute worst case you end up with 240V on a 120V circuit. It tends to wreck electronics and burn out light bulbs but it's unlikely to cause bodily harm.

author: richard.cs
author_rank: Super Contributor
timestamp: December 20, 2020, 06:55:27 pm
content: Quote from: james_s on December 20, 2020, 06:30:31 pmOur requirements are pretty similar in this respect - perhaps we just worry more about unlikely risks.Does your setup have to meet a particular resistance on the ground rods? It's very difficult in many soil types to get a low enough resistance to make much difference because it has to be low compared with the load impedances to meaningfully alter the voltage if the upstream neutral goes open circuit. Unless you happen to live in a salt marsh a couple of rods won't do a lot whatever size cable they're connected with. e.g. if you have 50 A of single-phase (or unbalanced) load and an O/C supplier-side neutral (upstream of the ground-neutral connection in your panel) then to hold the ground down to a "safe" 50 V you need your your rods to be down around an Ohm, even with earthed grids in the foundations that's a hard number to achieve.

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2020, 07:06:15 pm
content: It does, but it is rarely calculated, normally you just do what code requires, which varies by locality. Where I live we typically have moist soil with a lot of organic matter so good grounding is fairly easy. In some regions with sandy soil and less moisture the requirements are different, I think in some areas you bury a big loop of wire, I'm a bit hazy on the details having never lived in one of those areas I've only glossed over it in books.Here for example current (as of about 5 years ago when I looked it up) code requires either two grounding rods, or you can use a single rod if you can prove it provides an impedance to earth below a certain threshold, but almost everyone just installs two rods as it's easier than trying to prove that a single rod meets the requirements. Earlier revisions of the code required only a single rod, which is what my house has.

author: bdunham7
author_rank: Super Contributor
timestamp: December 20, 2020, 07:14:13 pm
content: Quote from: richard.cs on December 20, 2020, 06:55:27 pmI believe the spec is 25 ohms or two rods 6 feet apart. Nobody is trying to sink 50 amps fault current into just a ground rod, and if a ground rod is all you have, it won't happen. A fault like that in an installation with just the rod would result in some live earth and tingling feet.

author: richard.cs
author_rank: Super Contributor
timestamp: December 20, 2020, 09:33:13 pm
content: Quote from: james_s on December 20, 2020, 07:06:15 pmOne of the things I dislike about the US approach is that there's not much testing. You put two rods in and it's assumed to be good enough, doesn't matter if those two rods are into dry gravel and 1000 ohms each. The general approach seems to be construct as per proscribed method, assume it'll do in all situations. There are no situations in the UK where it would be acceptable to install an earth rod and not measure its resistance to earth. The UK equivalent "wiring regulations" expect a lot more understanding from the installer, the ability to calculate for specific situations, and to make a whole load of measurements after installation to prove that calculated performance is met. This does make us perhaps more reliant on installer competence, but has the advantage of flexibility.Quote from: bdunham7 on December 20, 2020, 07:14:13 pmWell quite, as the rod cannot sink anywhere near typical load current an O/C neutral gives the same tingly feet situation as on a UK TNC-S unless there are no other earth connections to that transformer's neutral.As an example of the point I made above, we don't have a spec for rod resistance in the UK*, what we have instead is a requirement that faults leading to a rise above 50 Volts should result in disconnection within 40 ms, and other faults should disconnect quickly enough to prevent fire (which is generally taken to be 5 seconds). Then in an installation where protection is offered by a 30 mA RCD, the absolute maximum rod resistance you can have is 1667 Ohms but with a 100 mA RCD it's be 500 Ohms. If you wanted to rely on an earth rod alone to trip a small MCB (unusual but allowed) then say for a 6 A B curve MCB you'd need at least 30 A to flow (but would be allowed to assume a negligible impedance fault and use the full line voltage**).* There's a general assumption that over 200 Ohms is likely to be unstable and subject to changing with the weather, but it's more that that is an oddly high value needing investigation, not a hard limit.** Because in this situation we're not worrying about offering "additional protection" to a human in the fault path as we might in many RCD applications and onto worrying about how much the installation earth rises during the fault).

author: TimFox
author_rank: Super Contributor
timestamp: December 20, 2020, 09:48:38 pm
content: In discussions of "ground resistance", I have always wondered how the measurement thereof is defined. I know that there are approved ground-resistance meters, but I have never used one.

author: bdunham7
author_rank: Super Contributor
timestamp: December 20, 2020, 10:18:37 pm
content: Quote from: TimFox on December 20, 2020, 09:48:38 pmYeah, the question is 'what is the other end', right? For a single ground rod, the actual certified meters use a connection to the ground stake and then two other test stakes are put in the ground some distance off. I'm not sure of their precise measuring method. I think it is more relevant to dissipating lightning strikes than allowing fault current, because fault current would always be referred back to the source, not 'real earth'. It also might tell you how large your 'equipotential zone' is for those that like to imagine that will keep them safe. For multiple ground stakes, you can test the resistance of your ground loop (one to the other) and Fluke actually makes a clamp meter that can do this in one step.

author: coppice
author_rank: Super Contributor
timestamp: December 20, 2020, 10:35:47 pm
content: Quote from: TimFox on December 20, 2020, 09:48:38 pmEven if you measure the ground resistance, it doesn't tell you the whole story. If the resistance you measure is mostly concentrated at one point in the path, you might see the path fuse at that point when a fault occurs, entirely removing the ground connection from providing further protection.

author: richard.cs
author_rank: Super Contributor
timestamp: December 21, 2020, 11:36:12 am
content: Quote from: bdunham7 on December 20, 2020, 10:18:37 pmGenerally the way that the cross-section of the current path grows with distance from the rod means that the total resistance between any two rods is almost entirely independent of the distance between them, and is dominated by a small volume of soil a few rod-lengths in radius around each - the resistance of this small volume of soil is what is normally meant by the resistance of a rod.To measure, it's usually a 3-wire resistance measurement. Two temporary stakes are put in far from the rod to be measured and from each other, current is injected between one and the rod under test, and the voltage between the rod under test and the other is measured. Yes, it can be confused by very non-homogeneous ground, but generally gives good results. Test equipment commonly measures with AC at a frequency not harmonically related to 50 or 60 Hz, the one I have used measures at 84 Hz.In a TT system (common in UK rural areas and some parts of Europe, not allowed in USA or Australia I think) there's no metallic connection from the consumers earth to the substation star point. In this case the resistance we actually care about is not actually the resistance of the consumers rod but the sum of that and the substation earthing, so a loop test is an alternative measurement approach - pass some current from line to earth and look at the drop in line-earth voltage as the earth gets pulled up (and the substation earth correspondingly pushed down, but generally by much less). The loop test measures the resistance we actually care about, whereas the 3-wire test measures the consumers electrode in isolation as this is almost always the dominant resistance and a standard max value is then assumed for the substation.

author: themadhippy
author_rank: Super Contributor
timestamp: December 21, 2020, 12:40:15 pm
content: QuoteAnd here we enter the catch 22 world of the uk electrical regs, supposedly before a supply is connected we need to provide the Zs and Ze, but you cant measure the Ze without a supply.

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2020, 12:46:05 am
content: Quote from: richard.cs on December 20, 2020, 09:33:13 pmIt's not ideal, but you see that sort of thing in many other regulations, and I suspect you'll find an example of one form or another almost anywhere in the world where things are done according to what the regulations require, and few people look at whether the regulation actually makes sense. In any given nation there are likely to be strengths and weaknesses in the regulation system for various things. You're always going to find some guys who do the minimum to get by doing a job that is legally acceptable and others who will go above and beyond, really understanding what they're doing and making it as good as possible.Whatever the case, grounding problems are not something that come up often enough to be on anyone's radar.

author: ocset
author_rank: Super Contributor
timestamp: June 06, 2021, 12:05:11 am
content: I wish JW (from first post) could listen to 8:00 to 8:54 of this.....and give his opinion. What do you think?But Didn't JW deal with this in 28:04 to 31:02 of his video from the top post? (repeated here)https://youtu.be/gZVx7GbAwlgWhat was wrong with having the charger outside the car, and just taking an isolated + and - to the car battery?Also, 27:11 to 28:30 of this below video shows the current sensing and switch-out circuitry that alleviates all the problems in JW's video......would you agree?So no earth rod is needed and its still perfectly safe, would you agree? Would JW agree?

author: mindcrime
author_rank: Unknown
timestamp: June 06, 2021, 04:56:27 pm
content: https://www.bbc.com/news/business-57253947?utm_source=pocket-newtab

author: David Hess
author_rank: Super Contributor
timestamp: June 06, 2021, 07:36:14 pm
content: Quote from: james_s on December 22, 2020, 12:46:05 amIn the US, the common situation is that the minimum required by regulation becomes the maximum allowed.

author: ocset
author_rank: Super Contributor
timestamp: June 06, 2021, 09:58:19 pm
content: Surely the "electric car charger with no earth rod" is no more electrically dangerous than this suicide shower?......... (which is used by many millions each day without tragedy)Any answers to post #107 much appreciated.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 12:37:56 am
content: Quote from: David Hess on June 06, 2021, 07:36:14 pmThat depends on who's doing the work. When it comes to electrical regulations at least, the NEC regulates the minimum, it's perfectly ok to do above code though. You can upsize the wire, have individual dedicated circuits for loads that don't require it, have more than the minimum required number of ground rods, etc.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 12:41:13 am
content: Quote from: treez on June 06, 2021, 12:05:11 amWhat happens when you want to charge and aren't at home or some other location with a compatible EV charger? When the charger is built into the car all you need is a charging cord you can carry with you and then you can plug in anywhere that power is available. It's usually capable of less current than an external DC charger but it's convenient to have.

author: bdunham7
author_rank: Super Contributor
timestamp: June 07, 2021, 12:54:44 am
content: Quote from: treez on June 06, 2021, 12:05:11 amNothing is 'wrong' with it--that's how the DC charging systems work. Nothing preventing someone from making one for home use--there's no lower limit on power AFAIK, and if there is it's pretty low.

author: rstofer
author_rank: Super Contributor
timestamp: June 07, 2021, 01:50:27 am
content: Quote from: Ice-Tea on December 13, 2020, 01:48:19 pmWhich is why, in the US, exterior outlets and those in the garage have GFCI receptacles or breakers. AFAIK, the charger component in the garage (the car is in the driveway) also has GFCI circuitry.These cars have been around for a while and there simply aren't any dead bodies laying around.I have been driving EVs for about 8 years and am totally satisfied. My old Chevy Spark EV was a regular hotrod with over 400 ft-lbs of torque. Solidly in the 'muscle car' category. Sporty...My existing Chevy Bolt works very well for its intended purpose of general purpose driving.

author: David Hess
author_rank: Super Contributor
timestamp: June 07, 2021, 03:36:05 am
content: Quote from: james_s on June 07, 2021, 12:37:56 amIn my experience it depends on who is inspecting the work. I have witnessed exactly the situation that I described.

author: ocset
author_rank: Super Contributor
timestamp: June 07, 2021, 08:59:49 am
content: It seems that "common sense" is telling us that its a waste of time spending £10000 to put in a special earth rod in the property just because we have EVs.However, every single objection that has been raised in this entire thread has been dealt with in JW's video........and they are all, strictly speaking, illegal. (if you watch from 21:30 onwards JW debunks all the possible "work arounds".)This is the same reason caravans arent allowed to have PME supplies.

author: rstofer
author_rank: Super Contributor
timestamp: June 07, 2021, 04:46:52 pm
content: Quote from: james_s on June 07, 2021, 12:41:13 amThe charger that comes with a US EV runs on 120V and fits conveniently in the trunk of the car. There's even a blocked out storage cavity.There are 10s of thousands of high speed charging stations. California has a grant program with $1 billion dollars to create additional stations. Employers are installing charging stations, most government parking garages have charging stations, etc. Even drugstores in my town have charging stations. It simply isn't a problem UNLESS you want to drive from California to New York in anything other than a Tesla. Tesla has installed enough stations to make that trip possible but I don't know that they will charge any other vehicle.https://www.theverge.com/2018/1/2/16842816/tesla-model-3-la-new-york-record-cannonball-runBut, if you think about a vehicle that is driven a few miles per day, charging just isn't a consideration. A deeper discharge will take a longer time to recharge using the 120V charger but that doesn't mean the vehicle can't be used if necessary, given sufficient remaining charge. The bad news: A charge from total discharge takes about 3 days with the small charger.And, no, the 'grid' isn't going to collapse. In the evening, many businesses are closed and their total demand will far exceed that of the EVs. Practically every store is closed by 9 PM and I can schedule recharging to begin at that time, if I want. All I have to do is turn off my HVAC while running the high power charger (240V charger) and I would present the same demand to the utility. I don't have a high power charger and the small charger is only about 1200W. About the same as a microwave and far less than an oven.If you're paying attention, you will see that many manufacturers are introducing EVs and some are going as far as saying that by <some date>ALLof their vehicles will be electric. GM is on that list for total conversion by 2035. That seems like a LONG time... I don't understand why they can't do it by Thursday...https://mashable.com/article/traditional-carmakers-going-all-electric-vehicles/Yes, the EV revolution CAN happen. Fact is, it IS happening and will just snowball until internal combustion engines just aren't available. Yes, there will be millions on the road but fewer every year. I suspect by 2055 (20 years after GM's 2035 date) that everybody will be driving EVs. Just a guess...1.3% of the vehicles registered in California are all-battery EVs and 0.9% are hybrids which really don't count.https://tableau.cnra.ca.gov/t/CNRA_CEC/views/DMVDataPortal_15986380698710/STOCK_Dashboard

author: rstofer
author_rank: Super Contributor
timestamp: June 07, 2021, 04:49:49 pm
content: Somehow the horse and carriage was replaced by the automobile even though there wasn't a network of gas stations. It will all work out, just watch!

author: Siwastaja
author_rank: Super Contributor
timestamp: June 07, 2021, 05:04:54 pm
content: Quote from: rstofer on June 07, 2021, 04:49:49 pmI agree, especially because a network of charging stations is maybe an order of magnitude easier task than coming up with the whole infrastructure of refining oil, transporting it in fuel tankers all over the world, to pumping stations in large underground containers, then sell it to you. That didn't happen overnight.Power distribution is alreadyeverywhere, and yes, in 99% of cases sized properly; given modern technology power conversion is trivial, and a charger is some easily replicable (despite being modern), small and lightweight power electronics hooked up to the grid. The most difficult part seems to be the information technology infrastructureto let people pay, despite this part being 1:1 equal to the gas stations, go figure. Still in 2021, the biggest obstacleby far(in Finland at least) is not not being able to find a charging station, but charging station being non-functional due to technical reasons not related to power distribution or power electronics in any way. I.e., the payment app is broken-by-design because it's overengineered by monkeys.At the same time as charging options evolve, need of fast charging reduces due to increased battery capacity.2020 was clearly the "start" of large-scale road electrification and 2021 shows the increasing trend. My guess is the naysaying becomes old grumpy men's art in maybe 2025, but of course it will take maybe another decade or two to electrify 50% of the traffic even in so-called "developed" countries.And it's not a trivial task. For example, the situation in Germany seems to be that electricity is so freaking expensive and fossil fuels still fairly acceptable price that driving an EV is not any cheaper or is even more expensive. In Finland, OTOH, an EV can actually pay itself back due to surprisingly cheap electric energy.

author: Gyro
author_rank: Super Contributor
timestamp: June 07, 2021, 05:30:10 pm
content: Quote from: treez on June 07, 2021, 08:59:49 am£10000 for an earth rod? Only on planet treez.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 05:38:35 pm
content: One of the biggest obstacles I see in my state, ironically since there are so many politicians pushing the "green" thing is that the taxation is totally backwards. The yearly licensing for EVs has a $150 surcharge due to not paying a gas tax, which I suppose could in some ways be reasonable but then on top of that they grossly overvalue cars for the regional transit task. My friend has a Spark EV that he paid $10k for several years ago, today it's probably worth around $8k yet the state says it's worth $26K and the result is a nearly $500 annual fee to renew the license. Used Nissan Leafs which typically sell for $5k-$10k are also assessed by the state at $18k-$28k. Older EVs depreciate very rapidly because people don't want to take a risk on an old battery that is still many thousands of dollars to replace so the way the state calculates value is totally unrealistic. People are going to have to change their mentality on what is reasonable to spend repairing an older car I think. For reasons I have never understood, most people balk at spending more to repair a car than the car is worth, makes no sense to me since you always spend more on a car than it's worth, when you buy a brand new car it is instantly worth less than you paid and when you repair an older car you are paying for transportation, not making an investment. Anyway the point is they depreciate rapidly and if the politicians want more people to make the switch they need to stop penalizing those that do with exorbitant licensing fees based on totally bogus valuations. If the state insists my car is worth 4 times what they sell for on the open market then they better be willing to make up the difference when someone hits me and totals it because the insurance won't even come close.

author: coppice
author_rank: Super Contributor
timestamp: June 07, 2021, 05:39:00 pm
content: Quote from: Gyro on June 07, 2021, 05:30:10 pmIf you want to tear up a driveway, as that video describes, and lay a new one with earthing capabilities, you are looking at a few thousand pounds. If you want a larger scale earth, you need to do some serious earth moving in a large garden. £10000 might be at the high end, but this is not a cheap job.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 05:41:39 pm
content: Quote from: coppice on June 07, 2021, 05:39:00 pmWho is actually going to do that though? There are millions of EVs on the roads, my region is crawling with them, I have never even heard of someone tearing up their driveway to add earthing. Nobody does anything at all to their electrical service, they just install a 240V circuit in their garage if they do anything at all. Many people who drive less just plug into a normal wall socket.

author: coppice
author_rank: Super Contributor
timestamp: June 07, 2021, 05:50:01 pm
content: Quote from: james_s on June 07, 2021, 05:41:39 pmWhat relevance to the discussion does that have? We know people just install a cheap protection circuit in most cases, or use one of the leads that plugs into an ordinary power outlet. However, the discussion has been about the inadequacies on that solution under fault conditions, the responses being introduced in wiring regulations, and the eye watering cost of retrofitting a suitable earth in an existing dwelling.

author: bdunham7
author_rank: Super Contributor
timestamp: June 07, 2021, 05:59:36 pm
content: Quote from: Siwastaja on June 07, 2021, 05:04:54 pmElectricity is technically easier in some ways, but here's a photo that illustrates two of the issues you raise at the same time.This is the gas station that I go to on the now rare occasions I buy fuel. I timed it, and it takes a car at the back of the line, before the bend, 9 minutes to get through the line and get a full tank of gas. There are 16 pumps and at 15 cars per hour (less than the 20 per hour I observed), 240 cars per hour are getting a full 'charge' that represents at least as much range as a top-shelf electric model. Assuming you can fully charge a long range electric car in an hour at 100kW, you would need 240 chargers. That would require 8-10 times the space and 24MW of electricity to match the capability of this gas station. Adjust the scale and assumptions as you see fit.The other issue is the blue truck that hasn't quite entered the fourth lane from the left. I can't see it clearly to identify the year exactly, but that truck is at least 30 and perhaps 40 years old--and every single part of it is probably available new or remanufactured from various parts suppliers.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 06:03:45 pm
content: Quote from: bdunham7 on June 07, 2021, 05:59:36 pmThat's true, however there's another factor that helps to mitigate this. EVs can be charged at home at night, that is one of the greatest advantages they bring to the table. Rapid charging stations are for times when you need extra range, or for people who lack the facility to charge at home or to charge at sufficient power to get the range they need. A typical EV owner will probably charge at home 95% of the time and only use the charging stations on specific occasions. If people could gas up their ICE cars at home the lines at gas stations would be much smaller.

author: Gyro
author_rank: Super Contributor
timestamp: June 07, 2021, 06:14:18 pm
content: Quote from: coppice on June 07, 2021, 05:39:00 pmThese days there are things like pneumatic 'moles'. We had to have the mains water supply feed pipe to our house replaced a couple of years ago. Minimum disruption, a couple of small holes in strategic 'soft' places and no disruption of existing services or hard landscaping. It only cost a few hundred pounds (including drilling the pipe up though the foundation and connection to the water meter and provision of new stop cock).I'm not commenting on whether it is necessary to put the charger on its own TT system or not, but it would be a very simple to mole an earth lead, even in a protective conduit to a needed location. The earth rod itself is very simple to install and terminate.

author: coppice
author_rank: Super Contributor
timestamp: June 07, 2021, 06:45:56 pm
content: Quote from: Gyro on June 07, 2021, 06:14:18 pmTry watching the video. and look as the scale of earthing he is talking about to achieve the desired quality of earthing. That would require a lot of mole holes, which I think would disturb the ground quite a lot.

author: rstofer
author_rank: Super Contributor
timestamp: June 07, 2021, 06:51:07 pm
content: Given that GFCI devices are typically used on outdoor and garage receptacles, who cares what the ground return measures? The devices measure the difference between the instantaneous outgoing and return current with any imbalance being attributed to a ground fault which results in the device tripping. These devices do not measure ground current nor do they even require the presence of a grounding conductor. They don't even assume that the system was grounded at the source. It's just a matter of current balance; what goes out comes back or the device trips. Simple as that!This tripping occurs instantaneously at around 4-6 milliamps.https://code-authorities.ul.com/about/blog/understanding-ground-fault-and-leakage-current-protection/This purported grounding issue is nonsense. If it were a real problem, we would have bodies piling up on the streets. And we don't!I actually have a 240V charger that I have never installed. It is a Bosch unit and the box is FULL of electronics. Somewhere in there I suspect there is some kind of GFCI functionality in addition to a GFCI breaker at the source.240V GFCIs seem to be quite common (I have never used one), particularly for hot tubs. Makes sense!I think we have this under control!

author: Gyro
author_rank: Super Contributor
timestamp: June 07, 2021, 07:10:11 pm
content: Quote from: coppice on June 07, 2021, 06:45:56 pmI did watch the video (in fact I watch all of JW's stuff when he posts it, his contribuitions to SparkyNinja too). Again, mole'ing is minimally invasive. You wouldn't need to go as deep as a water pipe (frost protection) so smaller holes. Even with the water ones, they re-filled, saved and replaced the turf etc. You couldn't see where they'd been.P.S. SparkyNinja is areallyuseful channel when it comes to technical analysis of the details of the regs, upcoming revision changes etc.https://www.youtube.com/c/SparkyNinja/videosCheck out the one on the proposed earthingbonding of all the rebar in the foundations coming up in 18th Edition Amendment 2.

author: David Hess
author_rank: Super Contributor
timestamp: June 07, 2021, 07:55:57 pm
content: Quote from: james_s on June 07, 2021, 12:41:13 amAfter the fires in California and the winter storm in Texas , I wonder what happens when you must travel but no power is available for charging. In both cases, there are examples of people with electric vehicles who were stranded.Quote from: james_s on June 07, 2021, 06:03:45 pmIn the US, about a third of people do not own their own home, and about a fifth of people live in apartments or condominiums. How do they charge their electric vehicle at home?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 07, 2021, 08:07:19 pm
content: Quote from: David Hess on June 07, 2021, 07:55:57 pmIf power is out, gas pumps also don't work. And those that aren't probably have massive queues.

author: Fungus
author_rank: Super Contributor
timestamp: June 07, 2021, 09:01:33 pm
content: Quote from: opampsmoker on December 13, 2020, 01:02:41 pmDespite all the hundreds of thousand of people that are already doing it...?

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2021, 10:29:13 pm
content: Quote from: David Hess on June 07, 2021, 07:55:57 pmThe same thing as happens if there's no power and the gas stations can't pump gas. That actually happened here about 10 years ago when a huge storm rolled through, one of those once in a lifetime situations where it had rained heavily for weeks and then massive winds tore through and knocked down a lot of lines including large transmission lines feeding substations. For about a week gas was scarce, the stations had it in the tanks but they didn't have power to pump it or do business. You'd think they would have generators but most didn't. It's prudent to keep your fuel tank full or your battery charged during fire/storm season, and if you live somewhere that has unreliable power, get a backup generator. It's perfectly possible to charge an EV from the output of a portable generator in emergencies, it isn't even all that horribly inefficient from a miles per gallon standpoint. Just for fun I calculated that charging a Tesla Y from a Honda EU2000i generator would result in about 20mpg, and in that specific use case a non-inverter generator would probably do even better.Renting a home does not preclude charging at home, it may preclude rapid charging but you never know, some landlords may be willing to have a circuit installed, most houses at some point will probably come with one, it adds peanuts to the cost of building the house. The 1/5 who live in apartments and condos are not the best candidates for EVs, but that doesn't matter, they can continue to drive conventional gas cars. It's not like apartment and condo parking areas couldn't be outfitted with power outlets for charging, it's not going to happen right away, but if one were going to build a new complex it would make sense to build in provisions for it if it's an area likely to have high EV ownership. It's certainly a nice perk that would greatly increase the desirability of a particular complex and the cost could easily be rolled into the rent or dues. Totally solvable problem. Until then, condo/apartment dwellers who wish to drive EVs can rely on rapid charging stations, they're only 1/5 of the population, that's a tiny fraction of the people who currently rely on gas stations.

author: TimFox
author_rank: Super Contributor
timestamp: June 07, 2021, 10:47:52 pm
content: Also, urban parking garages sometimes have charging stations, since the vehicle will be there for a few hours.

author: David Hess
author_rank: Super Contributor
timestamp: June 08, 2021, 01:44:35 am
content: Gas stations can at least in theory operate pumps off of backup power, and some areas in evacuation zones require this now, and always accept cash.I can store gasoline, but if I stored gasoline for charging my electric vehicle, then I need a backup generator also. But storing electrical power is a lot less economical.

author: james_s
author_rank: Super Contributor
timestamp: June 08, 2021, 05:38:54 pm
content: Well if you live in an area where power outages are common, you probably already have a backup generator. If you don't and you want to get an EV then it is probably prudent to get a generator, they are not all that expensive. You can store gasoline for a little while, but it goes bad eventually, especially the crap most places sell that has ethanol in it. If you plug the car in every night when you park then having backup power is less important, sure it's possible to get caught with an empty battery, but it's equally possible to get caught with an empty tank at the moment disaster strikes, and getting gas in an emergency can be as challenging as getting electricity.

author: David Hess
author_rank: Super Contributor
timestamp: June 08, 2021, 06:03:48 pm
content: Quote from: james_s on June 08, 2021, 05:38:54 pmWill an electric vehicle charger limit its input current based on the source capability? Or are you stuck using the slowest charging mode with a generator that has excess capacity? A lot of generators with 240 volt outputs will not support a full 240 volt load. I guess it would not matter if you assume that you have time to burn, but that might not always be the case.QuoteI think getting electric for charging is much more challenging than getting fuel. In the example I saw down in Texas, they ended up using their in-law's gasoline vehicle because they could get gasoline, but had no way to recharge their electric vehicle.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 08, 2021, 06:28:35 pm
content: Quote from: David Hess on June 08, 2021, 06:03:48 pmThe EVSE (wallbox) tells the car's onboard charger how much current it's allowed to draw. This can change dynamically, e.g. for solar systems. Depending on the EVSE (this is a UI issue), you can adjust the charge current to match the capability of the generator. You can also get EVSEs that use a current transformer on the incoming house supply to control charge current to keep the total load ( car and other loads) below a set limit.

author: james_s
author_rank: Super Contributor
timestamp: June 08, 2021, 09:42:02 pm
content: Quote from: David Hess on June 08, 2021, 06:03:48 pmThe only one I've personally played with enough to know was a Tesla and in that case yes, it lets you set the charging current to anything you want in 1A increments up to the maximum supported by the plug adapter you have attached to the input of the charging cable. There is a selection of plugs ranging from 13A 120V allowed for the NEMA-15 up to a maximum of 32A at 240V. I don't know if other EVs offer this capability but there's no technical reason that they couldn't so I assume that most do. It would be trivial to set the current right at the maximum continuous load your generator is capable of.

author: bdunham7
author_rank: Super Contributor
timestamp: June 08, 2021, 09:57:17 pm
content: Quote from: james_s on June 08, 2021, 09:42:02 pmActually, AFAIK Tesla is the ONLY one to offer that feature simply because the J1772 standard that every other car complies with works differently. It is true that any of those cars could have selectable maximum charge currents, but there would be little point in a J1772-compliant system. If you connect a J1772 charger to a generator that cannot supply the current that the charger is programmed for, you aren't using it as specified. Some, but not very many, J1772 chargers have easily selectable maximum charge currents. The control signal would be pretty easy to hack, though.

author: Calaverasgrande
author_rank: Contributor
timestamp: August 17, 2021, 02:36:56 pm
content: Strange, my sister and her husband have a Tesla and the Prius plug in hybrid. Seems to be working out ok.The real barrier to wider adoption of EVs would be scarcity of resources like rare earths and lithium.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2021, 04:39:33 pm
content: Quote from: David Hess on June 07, 2021, 07:55:57 pmThe low current charger that comes with the car plugs into any 15A U-Ground outlet including the GFCI device protected outlets in the garage. This is a SLOW charger, no doubt, and would be totally unsuitable were the battery continually used to depletion. But for the vast majority of our driving, shopping trips in town and such, we NEVER use more than about 20 miles of charge per day.There are always edge cases where EVs aren't practical. But I'll bet that a lot of people do most of their driving in or near some town and that their need for 'range' is more emotional than factual. If I can't wait for my slow charger, there are a couple of dozen fast charging stations around town. Many government buildings are providing charging stations for their employees.You just don't see these cars abandoned along the side of the road. Somehow, it all works out. We are into our 8th year of driving an EV and I suspect we will keep right on doing it.It's going to work out. Government is going to mandate it and that's the end of the discussion. Manufacturers are spending billions of dollars tooling up to build EVs with the stated intention of getting out of the ICE business altogether. We'll see...

author: David Hess
author_rank: Super Contributor
timestamp: August 17, 2021, 11:13:31 pm
content: Quote from: rstofer on August 17, 2021, 04:39:33 pmThe problem is that the very people who could make best use of an electric vehicle, lower income city dwellers, are also in the worst position for home charging, and those are an increasing majority of the population. Running a heavy extension cord to a carport, if they even have that, will be somewhere between difficult and impossible.That leaves home car charging dependent on infrastructure upgrades.

author: rstofer
author_rank: Super Contributor
timestamp: August 17, 2021, 11:30:15 pm
content: Quote from: David Hess on August 17, 2021, 11:13:31 pmThe cars are also expensive and I don't know about any tax breaks. There is no way the unemployed are going to be buying these cars.

author: David Hess
author_rank: Super Contributor
timestamp: August 17, 2021, 11:45:40 pm
content: Quote from: rstofer on August 17, 2021, 11:30:15 pmIn the US there are tax breaks but they are implemented by reducing income tax liability, which means they only apply if you have enough income to be taxed more than the rebate, which is not the case for most people. So the rebates only apply if you have a higher income.

author: rstofer
author_rank: Super Contributor
timestamp: August 18, 2021, 12:58:34 am
content: Actually, the tax rebate program for Chevy Bolts expired 3/31/21. IIRC, the original price with the super duper trim was pushing $50k. Kind of expensive.Quotehttps://www.motorbiscuit.com/used-chevy-bolt-20000-will-help-avoid-chip-shortage-stress-consumer-reports/Using up a $7500 of tax credit is no problem at all. It's a bummer that you can only get as much of a credit as your tax liability. If you only owe a couple of grand, that's all you can get.

author: james_s
author_rank: Super Contributor
timestamp: August 18, 2021, 05:03:05 am
content: It's kind of backwards here in Washington. There's a lot of talk about "green" in this super progressive region, yet EVs have a $150 electric vehicle surcharge applied to the annual licensing fee. It's because EV drivers aren't paying a gas tax, but do we want to encourage EV use or not? For the amount I drive $150/yr would eat up a lot of the incentive.

author: coppice
author_rank: Super Contributor
timestamp: August 18, 2021, 01:38:14 pm
content: Quote from: james_s on August 18, 2021, 05:03:05 amIf they lose a lot of tax revenue from gas sales, they are going to have to grab it back from some other form of taxation. This is a much bigger issue in Europe, where the tax on gas and diesel is much bigger. So far in the UK the only move seems to have been a big increase in in the annual car tax on cars over 40k pounds, and some differentiation between the tax on cars of different fuel types, and those bogus CO2 ratings which the makers game.

author: rstofer
author_rank: Super Contributor
timestamp: August 18, 2021, 01:49:54 pm
content: California is working on a mileage tax to ensure that EVs pay for their use of the roadway. We drive so little that this just doesn't matter to us but before I retired I was driving 120 miles per day round trip. With the new tax stream, you would think that the state would drop the gas tax. The taxes on gasoline are probably in excess of $1/gal with some going to the feds and the rest to the state. That doesn't include sales tax which should wind up with the county.The working folks get hammered on gas tax and adding EVs by adding an all-encompassing mileage tax on commuters just makes working even less profitable. No wonder nobody wants to go back to work.

author: coppice
author_rank: Super Contributor
timestamp: August 18, 2021, 02:07:10 pm
content: Quote from: rstofer on August 18, 2021, 01:49:54 pmI've seen a few things talking about moves in various places to mandate the use of a black box on every car to measure mileage, and charge accordingly for road usage. If it stopped there, there may be good arguments for these black boxes. However, if the government can track your total mileage they can track your every move, which sounds like a big brother's wet dream.

author: Monkeh
author_rank: Super Contributor
timestamp: August 18, 2021, 02:45:49 pm
content: Quote from: coppice on August 18, 2021, 02:07:10 pmYou know they record it on the MOT, right?

author: sokoloff
author_rank: Super Contributor
timestamp: August 18, 2021, 02:56:04 pm
content: Quote from: Monkeh on August 18, 2021, 02:45:49 pmYou know that writing down (or fetching over OBD2/CAN) the mileage once a year is dramatically less intrusive than a black box that has live access to the car, right?

author: Monkeh
author_rank: Super Contributor
timestamp: August 18, 2021, 03:01:15 pm
content: Quote from: sokoloff on August 18, 2021, 02:56:04 pmIndeed. But 'tracking the total' is, in fact, already done.I'd reject a black box out of hand even if they offered me free road tax (of which I pay very little anyway), free insurance, and Subway vouchers.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 18, 2021, 03:10:34 pm
content: JW knows what he is talking about but you need more than one fault to come a cropper. Wear your shoes?

author: coppice
author_rank: Super Contributor
timestamp: August 18, 2021, 03:14:35 pm
content: Quote from: Monkeh on August 18, 2021, 02:45:49 pmYes, but that seems to totally miss what I just wrote. Also, you do know they don't have MOTs for the first 3 years. Most cars move on to a new owner by that time, so who is responsible for the tax on those three years of miles? The company guy who had the car for the first year, doing lots of miles that were not recorded? The second owner who may have done few miles?

author: rstofer
author_rank: Super Contributor
timestamp: August 18, 2021, 03:18:59 pm
content: Quote from: coppice on August 18, 2021, 02:07:10 pmBut OnStar comes free with every new GM vehicle for the first <insert some number> of days. If you don't subscribe, they shut down the things you want but not the things they want. How else do they account for the fact that I get a monthly maintenance reminder showing tire pressure and an accurate mileage figure.Of course the car is being tracked! About the only way to shut it down is to disassemble the dashboard (nigh on impossible) and unwire the transmitter.

author: rstofer
author_rank: Super Contributor
timestamp: August 18, 2021, 03:26:23 pm
content: Quote from: coppice on August 18, 2021, 03:14:35 pmIn California, there is an 'accurate odometer' statement that is filed along with every title transfer. The seller has to certify that the odometer reading is correct. The buyer has every opportunity to verify that the vehicle they are buying does indeed show that mileage. Most often, the certification is on the title transfer document but there is a separate document if there are errors or omissions on the transfer paperwork.

author: sokoloff
author_rank: Super Contributor
timestamp: August 18, 2021, 05:44:59 pm
content: Quote from: Monkeh on August 18, 2021, 03:01:15 pmIn the totality of the message, of which you quoted only a portion, I don't think that the most sensible reading of coppice's message was an undue concern for knowing the total distance the car has travelled since its manufacture.

author: Monkeh
author_rank: Super Contributor
timestamp: August 18, 2021, 06:03:56 pm
content: Quote from: coppice on August 18, 2021, 03:14:35 pmThat is a fair point, but it could be changed to collect it yearly and at change of ownership. In my case I've always owned second hand cars for a number of years, so my mileage is a matter of near enough public record as a result.. This doesn't bother me, and equally paying road tax based on the actual covered mileage of the vehicle would not, as long as the collection is of coarse data, not a black box telling someone about every sharp acceleration I feel like making or how inefficient my gear choice is.

author: coppice
author_rank: Super Contributor
timestamp: August 18, 2021, 06:08:21 pm
content: Quote from: Monkeh on August 18, 2021, 06:03:56 pmJust how hard are you working to miss the point? There are several cheap practices that could be used to track mileage in large chunks (e.g. yearly) which would be cheap. Governments clearly aren't looking just for this. They want to track your car's every move.

author: Monkeh
author_rank: Super Contributor
timestamp: August 18, 2021, 06:12:54 pm
content: Quote from: coppice on August 18, 2021, 06:08:21 pmJust how hard are you working to miss a different point of view? Oh, never mind..

author: james_s
author_rank: Super Contributor
timestamp: August 19, 2021, 01:36:49 am
content: Quote from: coppice on August 18, 2021, 01:38:14 pmI realize that, but it still kind of rubs me the wrong way. There is so much lip service about being "green" in this region and then they go and give EV owners a slap in the face by charging them a substantial surcharge that discourages EV ownership. On top of that the valuation system they use in this state to calculate the licensing fee is completely broken. They use a depreciation model that is based on very optimistic numbers for a conventional ICE car and the result is not even close to reality. For example my dad had a Nissan Leaf for a few years, I think he bought it ex-lease for under $10k and then he eventually sold it for $5k when he bought his Tesla. That was reasonable market value at the time but the state still claimed it was worth $25k and charged accordingly for the licensing. A friend of mine has a Chevy Spark EV, he also paid around $10k for it used a few years ago, also fair market value. The state claims his car is worth $26k. Of course there is no way in hell insurance would ever pay anywhere close to that amount if it got wrecked. That total disconnect really bothers me, the insurance company says it's worth one amount and the government says it's worth 3-5 times as much and there's nothing you can do about it, no process to contest it. I know taxes are a necessary evil but I really hate these situations where it just feels like you're being raped and have no recourse.

author: sokoloff
author_rank: Super Contributor
timestamp: August 19, 2021, 01:53:02 am
content: Quote from: james_s on August 19, 2021, 01:36:49 amI'd be in favor of a system where the state would be forced to buy a car (or house) for 80% of the value they base any tax assessment on.You think my 7 year old LEAF is worth $20K? I disagree and hereby exercise my option to sell it to you for $16K.I'll go buy another one and do the same thing next month until you figure it out.