somewhat solved: Do any US outlets exist with thermal fuses/cutoffs? (nope!) - Page 1
Forum section: electronics / beginners

author: incf
author_rank: Frequent Contributor
timestamp: March 29, 2025, 05:55:45 pm
content: I'd like to find out if any models of US style 15/20A 120VAC outlets exist that contain a thermal fuse (cutout/cutoff).I recently stumbled across photos from an electricians forum - I was surprised. A quick google search  lead me to conclude that outlets melt due to worn contacts with some regularity.Source  speculates that thermally protected outlets either don't exist or are uncommon due to the additional cost (ten cents) for thermal fusing.https://electronics.stackexchange.com/questions/257539/why-not-include-a-thermal-fuse-in-electrical-outlets (various social media sources like)https://www.reddit.com/r/electrical/comments/1hbxjxp/had_an_outlet_melt_last_night/edit: attaching second example image from reddit in response to Stray Electron's post - I really think that a thermal fuse inside the body of the outlet would have tripped eventually in the case of the second image (these images were scraped together from random internet threads)edit2: more images for your viewing pleasureedit3: remember, the people who took these photos are not present in this thread.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 29, 2025, 06:39:10 pm
content: That burn was caused by a loose fitting plug and not by any kind of over current. Any kind of loose electrical contact will cause arcing and overheating of that one set of contacts. And the longer that goes on, the worse the connection why be and that makes the arcing even worse. I've noticed that a LOT of the Chinese made products have AC plugs where the two contacts are made of a single thin sheet of material and you have to wiggle them around in the sockets before the device will work. Each blade in the old, better grade, US made plugs were typically made of a piece of folded over brass and each piece had slight bend in it so each blade was slightly diamond shaped and they would wedge tightly into the socket and they made very good electrical contact.Newer (possibly foreign made) poor quality electrical sockets may also be a part of the problem but I KNOW that poorly made electrical plugs are definitely a problem.Take a good close look at the unburned contact in your power cord and then take your damaged outlet a part and look at the unburnt contact in it and you will probably see what I'm talking about.Since your problem was caused by arcing between the contacts a thermal overload switch probably won't prevent that problem and only help if the switch is located so close to the contacts that it can sense the overheating.And BTW you should go check your circuit breaker box and be SURE that no one has replaced the proper value circuit breaker with a larger breaker! Specifically check that circuit but it would hurt to check all of the other circuits as well. it's not uncommon for people to install a larger CB so that they can run larger devices such as a large vacuum cleaner or space heaters but it's dangerous as hell because the increased current could overheat the wiring in your walls, attic or basement and create a fire where you wouldn't see it until it's too late.Oh and PS. It's not only loose fitting plugs that can cause overheating like that, so can using the Stab connections on the outlet. Electricians love to use those but they are also notorious for working their way loose and then causing arcing. You should take that outlet out and see if it was the stab connection that failed or if it was the junction of the socket contact and the plug contact. It looks to me like the later but you need to find out.In a direct answer to your question: I've never seen a Nema 5-15 outlet with a thermal cutoff but I would not be surprised to find someone makes them. But IMO it's not going to fix your problem.Some general info in case you're not familiar with it.https://wissenergy.com/what-is-nema-5-15-plug/

author: floobydust
author_rank: Super Contributor
timestamp: March 29, 2025, 07:01:00 pm
content: That photo looks suspicious in that BOTH sockets are melted.What, both were worn on Line but not Neutral?Before we get out the pitchforks for a new safety solution, looks like there was something else to blame here.I've only seen really old, tired outlets decades old make a poor connection which just causes the cord to fall out.Interestingly there are better than residential grade; "heavy duty" or "extra heavy duty" or "industrial grade" or "commercial grade" outlets.They seem to grab the pins harder and have brass ground tangs.Why fuse it when that money can just go into building them better?

author: Xena E
author_rank: Frequent Contributor
timestamp: March 29, 2025, 07:12:02 pm
content: Good quality receptacles and plugs correctly loaded wouldn't do that.Quote from: floobydust on March 29, 2025, 07:01:00 pmYeah, but it's enough of a problem that in some parts of the world these are mandated... fear factor? Maybe, but they will detect that fizzling wirenut in the drywall...https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.youtube.com/watch%3Fv%3DlIit5k8QVj8&ved=2ahUKEwillsXa_K-MAxWRWUEAHVEGJ64QwqsBegQIDBAE&usg=AOvVaw2iyWt2ge9HwtA2MU2FxMDH

author: Stray Electron
author_rank: Super Contributor
timestamp: March 29, 2025, 11:21:11 pm
content: Not all of those pictures are of the same outlet!! The last picture clearly shows a rectangular outlet instead of the rounded outlet shown in the first pictures. Also the first pictures show that the fire was between the outlets and later pictures clearly show that it was only one socket that burned.That said, you can clearly see that the outlet that burned in the middle had stab wire connections and I would bet money that that is what caused the fire on it. The outlet that is burned at one end almost certainly had a bad plug to socket connection.

author: incf
author_rank: Frequent Contributor
timestamp: March 29, 2025, 11:52:44 pm
content: I feel like some sort of miscommunication has occurred.

author: Stray Electron
author_rank: Super Contributor
timestamp: March 30, 2025, 12:09:41 am
content: Quote from: Xena E on March 29, 2025, 07:12:02 pmIn the real world, a lot of people discover the problem when they touch the outlet and notice that it's warm to the touch. Firefighters use a thermal camera to check electrical outlets and switches but I expect that an IR thermometer gun would also detect overheating. But anytime that someone notices that a light, or other device that is plugged into an outlet, is flickering then they should investigate or have someone knowledgeable investigate and find out why.There are also paints that change color after being exposed to certain temperatures. I'm a bit surprised that some of the safety people haven't mandated that every outlet cover incorporate some some of color changing device that would warn when an outlet has overheated.

author: bdunham7
author_rank: Super Contributor
timestamp: March 30, 2025, 12:15:43 am
content: Quote from: incf on March 29, 2025, 05:55:45 pmNot the outlet, but my 120V EV charger was recalled and replaced with a unit that had a temperature sensor in theplug, precisely for this sort of issue--causing outlets to catch on fire when run at full power (12A) for extended periods. The problem was worn/loose outlets or wires, but the car manufacturer got blamed because its chargers appeared to be the cause.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: March 30, 2025, 09:03:50 pm
content: Quote from: incf on March 29, 2025, 05:55:45 pmHonestly, I'm a bit skeptical on this being the reason. I've encountered a lot of failed thermal fuses, which I'd imagine would be the more-likely reason that thermal fuses aren't used on electrical outlets. The low risk of fires from electrical outlets, and higher maintenance costs is probably the major players.Electrical outlets already have multiple fail-safes, such as circuit breaks with overcurrent protection at the panel, the housing being made of flame-retardant materials, and that the devices themselves often have fusing incorporated within. Had it been a factor-of-cost, you'd see large businesses or hospitals incorporating thermal fuses into their outlets, but this isn't the case either.

author: macboy
author_rank: Super Contributor
timestamp: March 30, 2025, 09:13:31 pm
content: Curious that they all* seem to be wired with the quick-stab connections at the back, instead of using the screws on the side. Those stab connections are very poor and are known to be problematic, but they are easy and fast, so most electricians just use them anyway.(* all of them where we can see where the wire terminations are made)

author: themadhippy
author_rank: Super Contributor
timestamp: March 30, 2025, 10:03:01 pm
content: QuoteHere in the uk they released a 13A socket specifically for car charging due to the supposed overheating issue,seems a bit unnecessary when the specs for a standard 13A socket sayQuote

author: golden_labels
author_rank: Super Contributor
timestamp: March 30, 2025, 11:30:14 pm
content: I had a case of a smoldering outlet at my parents’. It wasFrench (CEE 7/5). I was home and awake at the time, and noticed the problem. But wallpaper over the outlet was already charred and smoldering too, so it was a close call.Nothing was attached, so neither overcurrent nor a poor connection to the plug can be blamed. I doubt a thermal cut-off or any other reasonable safety measure in the socket would help.

author: GLouie
author_rank: Regular Contributor
timestamp: March 31, 2025, 12:43:46 am
content: I am not a license electrician, but have not heard of outlets with thermal fuses. And not so sure what would cause those fires.However, in the USA, even US companies make approved outlets that are cheap, use push-in (stab) connections (usually with optional screws), and are just terrible at holding plugs securely for any length of time. They are approved though, as cheap as possible (under $1 USD), and fast to wire up, so are usually used in most residential construction.Whenever I find a loose socket or build my own power boxes, I always use what is called "specification or spec grade" outlets in the US, which tend to cost more like $3 USD. They are built much better inside and out. You can also buy much more expensive outlets such as hospital grade and so on, but I am not sure they are so much better as to be worth it.

author: MrAl
author_rank: Super Contributor
timestamp: March 31, 2025, 08:55:00 am
content: Quote from: incf on March 29, 2025, 05:55:45 pmHi,Sometimes without realizing it we think about the ideal case and don't realize how non ideal it turns out in the real practical world.One of the requirements with a thermal fuse is it has to make physical contact with the object being detected. In the case of the prongs, it would have to make direct contact with both prongs, which means two thermal fuses for that.Unfortunately, that's not the only failure mode. What else can happen is the screws that hold the wires in place can loosen up due to thermal cycling. They get warm, they get cold, they get warm, they get cold, over and over again throughout the years. This would bring in another two thermal fuses one for each screw contact strip. So now we are already up to at least four thermal fuses, and we have to find space to fit them in so they don't cause a problem themselves.This may be possible, but it would require a new design, and it would have to be carefully done and tested over time. The question is, how feasible would it turn out.I've only seen one socket create a black area on the outlet in my lifetime. It turned part of the plastic black and melted it. That was due to a loose or dirty contact. There was no fire and no smoke.When I worked in the industry the test for a bad connection was to hold the wire near the connection point and see if it felt hot. If it felt hot, it could be a bad connection and the crimp might have needed to be done again. That's something we can do at home too. Hold the plug for a few seconds and see if it feels hot or too warm.Maybe the solution for those possibly really bad cases is a good smoke detector placed at strategic locations. The outlets that are most at risk would be those that carry current of about 5 amps or greater. The lower currents don't usually cause a problem. As we get closer to 20 amps the risk goes up a lot.

author: tszaboo
author_rank: Super Contributor
timestamp: March 31, 2025, 09:16:47 am
content: Quote from: incf on March 29, 2025, 05:55:45 pmWhen I went to the US, and saw the US outlets IRL for the first time... Honestly, I was shocked how terrible quality and design they are. Pun intended. Not only you can short the still live connectors externally, when it's not plugged in correctly. The outlets are also supposedly 20A, which is 25% more than the standard EU 16A outlets, that have larger contact surface. Doesn't sound like much, but for any given contact resistance, its 55% more dissipation.Honestly, you guys should switch to IEC outlets. Then maybe worldwide adaptation of it could begin.

author: Berni
author_rank: Super Contributor
timestamp: March 31, 2025, 09:59:32 am
content: Problem is the shitty design of US power outlets.The contacts on US outlets are pretty low force, then over time they get even looser trough regular use. Eventually getting so high contact resistance that they catch fire under extended high load.Problem is that the US is too suborn to switch to a better plug design. But as a stop gap measure you could switch to using some of the higher current rated 20A or 30A NEMA plugs. Snip the cord on high power draw appliances and wire it into a new plug. Tho the problem with that is that you likely also have to put those wall outlets on an appropriately sized circuit to be code compliant.

author: MrAl
author_rank: Super Contributor
timestamp: March 31, 2025, 07:14:35 pm
content: Quote from: Berni on March 31, 2025, 09:59:32 amHi,I am not sure what you mean. A new outlet at Home Depot has decent contacts.I won't argue that there are no better though. I got a couple power strips where you REALLY have to yank that thing and rock it back and forth to unplug it. It's almost TOO tight in thereWhat else happens is the appliances sit around and get tarnish on the plug prongs. That raises the contact resistance. I always check mine and clean them if they need it. I use the tip of one of those slide type razor knifes to gently scrape the prongs clean. They get nice and shiny and with light scratches on the surface, which are now known to cause better contact.We are lucky these days I think that most things run on wall warts. These things do not draw much current so even with increased contact resistance there's almost no chance a fire would happen ... just not enough power dissipation available to even melt the plastic. The risky things are devices like microwave ovens, air conditioners, hot plates, and of course the worst of the worst: the hot element space heater, I hate those things.

author: tooki
author_rank: Super Contributor
timestamp: March 31, 2025, 07:24:21 pm
content: Quote from: tszaboo on March 31, 2025, 09:16:47 amA standard US outlet is 15A, not 20.How do you figure that an EU outlet has larger contact area? In both US and EU outlets, the contacts are usually just on two sides, so either flat things sandwiching a flat thing (US), or flat things with cheaply stamped dimples sandwiching a round thing (EU). Most EU (or Swiss) outlets I've seen aren't that great at having a large contact area with the round pins that go in them.

author: tooki
author_rank: Super Contributor
timestamp: March 31, 2025, 07:31:51 pm
content: Quote from: Stray Electron on March 29, 2025, 06:39:10 pmThis is not a US-vs-China issue. AFAIK, the US plug standard has never required (nor recommended) pins that bulge outwards. It is expected that the socket provides ALL of the clamping force.Low-cost plugs today, as well as US-made plugs in the past, use the folded brass construction. The best style of plugs don't use folded sheet metal at all, but rather a single thick piece of metal for each prong.The actual problem is that cheap sockets -- which in USA is 99% of the ones installed in residential systems, and in many offices, etc. -- use awful contacts made of an alloy that does not have enough springiness, so after a few hundred cycles, they are loose. Even the best commercial-grade sockets give out after heavy use (e.g. airports, where dozens of people per day plug in their chargers).Indeed, plugs with bulgy pins would only accelerate the rate at which sockets wear out.

author: bdunham7
author_rank: Super Contributor
timestamp: March 31, 2025, 07:47:30 pm
content: Quote from: tszaboo on March 31, 2025, 09:16:47 amI think the problems with US plugs/sockets are a bit overstated. There really aren't massive numbers of flaming, melting outlets here and when it does happen it is usually something that is more than 50 years old or has been abused. I've personally only seen a few issues at all in my lifetime and no fires. I would not trade my plugs for the EU variety, I might consider the UK type, especially if I can get a 3kW kettle.Quote from: tooki on March 31, 2025, 07:24:21 pmWell, that's complicated. Actually most outlets today have contacts rated for 20A because it is allowed to install them on 15A or 20A circuits. These outlets commonly come in the NEMA 15-5 configuration (both prongs upright). The NEMA 5-15P plug is only supposed to be used on appliances that draw 15A intermittently or 12A continuously. The NEMA 5-20 style, with one prong horizontal, or the combo-type that will accept both plugs, are rated for 20A or 16A continuous andmustbe installed on a 20A circuit.

author: TimNJ
author_rank: Super Contributor
timestamp: March 31, 2025, 07:55:12 pm
content: I would say that AFCI is more of answer to this than a thermal fuse, provided it actually detects the wonky connection.

author: tooki
author_rank: Super Contributor
timestamp: March 31, 2025, 08:03:58 pm
content: Quote from: bdunham7 on March 31, 2025, 07:47:30 pmIt's not complicated. Thestandardplug and outlet are the 15A variants: NEMA 5-15P plugs and 5-15R receptacles.While 20A receptacles (NEMA 5-20R) are becoming more common, I do not believe any NEMA 5-15R receptacles are 20A-rated, because that frankly makes no sense: there is no circumstance whatsoever where a device should be drawing 20A through a 5-15P plug.What you call the "combo-type" receptacle is theonlytype of NEMA 5-20R receptacle -- there isn't a version that accepts NEMA 5-20P plugs exclusively.

author: bdunham7
author_rank: Super Contributor
timestamp: March 31, 2025, 08:48:57 pm
content: Quote from: tooki on March 31, 2025, 08:03:58 pmYou missed the point--the NEMA 5-15R receptacles I'm referring to are approved for installation on 20A circuits, not for using devices drawing more than 15A. The NEC specifically allows this and the only relevant restriction is that the 20A circuit cannot only have a single 15A outlet--but a duplex one would be OK. This setup is common and makes sense since not all of the 20A has to be used by one device. However, even though appliances shouldn't draw more than 12/15A that's irrelevant--it is the circuit breaker rating that determines what the rating of all downstream components must be. You'll commonly see this explained as the 15A receptacle having a 20A "pass-thru" rating, meaning that the connections are rated 20A and can be used to daisy-chain sockets in a 20A circuit, but I can tell you that even though they can't actually state that each socket is good for more than 15A they are using the same contacts as a 20A device. That way if your toaster or space heater has an internal partial short and starts drawing 19A, the socket won't burn up before the breaker trips.QuoteI can't find one right now, but I'm sure I've seen them. They're for dedicated applications, not general household use. But you are right in that they wouldn't be called NEMA 5-20R as that is specified as the cross/combo style.

author: WattsThat
author_rank: Frequent Contributor
timestamp: March 31, 2025, 08:54:00 pm
content: Tooki summed it up best, it’s not complicated.What everyone has missed is the obvious. The photos of all the failed receptacles show that the connections were made by pushing the wires into the friction “back-stab” holes rather than being connected using the side mounted screws.This is the primary cause of all receptacle/plug failures with resulting fires in the US. Honestly, they should be banned, they’re that bad. It’s a combination of lazy, cheap and the unknowing that result in these types of failures.Lazy & cheap is electricians that know better using the back-stabs because 1) they're the cheapest available 2) they’re really fast to wire and 3) they’re paid by the job, not the hour.Cheap & unknowing are the DIY’ers that buy the cheapest and don’t know how to properly wire using the side screws.Arc fault breakers are now required by the national electrical code for any occupied spaces. Unfortunately, they have their own set of problems, like tripping when used on appliances with universal motors where there’s a switch in a dc circuit.NEC allows for 15 amp receptacles on 20 amp circuits so long as multiple receptacles are present on the branch circuit and no, they don’t make receptacles with thermal fuses.

author: Berni
author_rank: Super Contributor
timestamp: April 01, 2025, 06:28:26 am
content: I also seen EU wall outlets in the "back stab" style. I don't trust them but luckily they seam to be pretty rare, the majority of them use classical screws.That is not to say EU plugs are the best plugs. They do have their downsides just as well. For one the insertion force is very high on them(made even worse if they have child safe shutters), the force is so high that yanking on an extension cord has a chance of ripping the whole wall outlet out of the wall (not a brand new one but some abuse later the wall attachment can weaken) this causes live wires to be exposed as the outlet is hanging out of the wall. The earth pin in EU outlets also has a tendency to get bent out of shape after abuse, once bent enough a forceful plug insertion can flatten the whole pin into the plug where it doesn't make contact. They also also not polarized at all so there is a 50% chance of swapping L and N when plugging it in. The lower power non earthed variant of the plug has mostly plastic pins that break easily.The UK plug is probably the closest we get to a perfect mains plug.Also the US split phase thing is a good idea, being able to get double the voltage when desired, but if only they had more standardized plugs for 220V (especially if there existed some sort of combo outlet that is compatible with both 110V or 220V plugs simultaneously).

author: Jeroen3
author_rank: Super Contributor
timestamp: April 01, 2025, 07:06:02 am
content: I have not seen a receptacle with screws in decades in the eu. It's not a problem here.Basically everything is going spring-connectors here, even the breakers, because: you can't do it wrong.You don't need a torque screwdriver, you can't fit the wrong size, you can also fit stranded and it's automatically ip2x. (which means touch safe)Besides, if you regularly have your installation inspected, the ZLNmeasurement will find worn out sockets.I believe the UK calls this EICR, the Belgians call this AREI, we call it NEN 1010.The management solution to your problem is regular inspections.The engineering solution to your problem is an AFDD.The solution to your problem is to invent better plugs.

author: themadhippy
author_rank: Super Contributor
timestamp: April 01, 2025, 10:24:20 am
content: QuoteNo need, once the yanks rejoin the commonwealth we'll mandate they use the british electrical system,including our plugs and sockets,we'll even let them use MK quick fix sockets so they dont miss there back stab connections.

author: Gyro
author_rank: Super Contributor
timestamp: April 01, 2025, 11:18:48 am
content: You're kidding. When I worked for a US company, we used to celebrate independence day in the UK office! If nothing else, a day of peace andnot getting hassleproductivity.

author: golden_labels
author_rank: Super Contributor
timestamp: April 01, 2025, 11:27:47 am
content: Quote from: Jeroen3 on April 01, 2025, 07:06:02 amDepends. In here the inspector just puts a meter in a single outlet. In my case it’s an outlet that nobody ever used, because it’s located exactly over a gas stove.

author: Gyro
author_rank: Super Contributor
timestamp: April 01, 2025, 11:34:27 am
content: Maybe an (unintended) advantage of ring circuits - during an EICR here, they go round and measure all the sockets. An anomalous reading could indicate a break in the ring (or just a worn socket).

author: MrAl
author_rank: Super Contributor
timestamp: April 01, 2025, 11:59:34 am
content: Quote from: tszaboo on March 31, 2025, 09:16:47 amI'd love to see the US switch to 230vac rather than 120vac (or 115vac as it is sometimes called), along with the required outlet type to go with that.For one thing, an appliance at 230vac only has to draw one-half of the current as a 115vac device has to draw in order to run at the same power level.That would achieve a lot, the first being it would reduce the stress on the power grid with only 1/2 of the current flowing through all the wires on the low voltage side (probably the very high voltage side would have to stay the same).This would be a very difficult change however that's the unfortunate part. Virtually every household would have to have their own transformer to step it back down to 115vac unless they buy all new equipment that runs on 230vac.As to the outlet quality, I don't see the problem though because the outlets I have seen in the past 20 years (at least) were ok. Maybe there are some really cheap ones out there, but the manufacturer would be taking one big hell of a risk due to lawsuits and such.

author: themadhippy
author_rank: Super Contributor
timestamp: April 01, 2025, 01:25:44 pm
content: QuoteI've corrected that for you,plenty examples of drive by testing to be found,or limitations due tosparky being lazyinaccessible sockets,like behind a wardrobe

author: Monkeh
author_rank: Super Contributor
timestamp: April 01, 2025, 01:55:22 pm
content: Quote from: MrAl on April 01, 2025, 11:59:34 amEr, why? They already have both 120V and 240V delivered.Quote from: MrAl on April 01, 2025, 11:59:34 amThe part which isn't part of the grid or stressed? .. the same part where the largest loads are already operating at 240V?

author: Haenk
author_rank: Super Contributor
timestamp: April 01, 2025, 05:59:15 pm
content: Quote from: Berni on April 01, 2025, 06:28:26 amI think the screw terminals are rare now; push type installation is far more common. And I have installed a three digit number of those in my office and my home, and had not one failure in 20 years. Of course, these are not below 1 USD, but were about 2,50EUR each back then, now about 4 EUR (not including frame). But that's stuff were you shouldn't buy the cheapest option, IMHO. And I expect them to last *forever*.

author: Gyro
author_rank: Super Contributor
timestamp: April 01, 2025, 06:45:14 pm
content: By coincidence, it appears that somebody has come up with a UK socket with thermal and other fault detection, potentially replacing / suplementing AFFDs. Not much help to the OP and our US friends though.Starts at 4:34...

author: tooki
author_rank: Super Contributor
timestamp: April 02, 2025, 05:49:14 am
content: Quote from: bdunham7 on March 31, 2025, 08:48:57 pmThansk for clarifying what you meant with 20A pass-through.Are you sure you’re not thinking of the 6-20P (240V) plug? As best I can tell, there is no NEMA standard for a 120V 20A-only receptacle.

author: tooki
author_rank: Super Contributor
timestamp: April 02, 2025, 05:53:30 am
content: Quote from: MrAl on April 01, 2025, 11:59:34 amThe grid doesn’t operate at 120 or 240V, so it would not see any difference. It’s transformed from some number of kV down to 240V right near your house.

author: Jwillis
author_rank: Super Contributor
timestamp: April 02, 2025, 08:12:23 am
content: What I'm seeing in your photos is not a fault of the socket. It a fault in poor or non existent Earth grounding. As some one has mentioned before, much of the burning is originating on the common. Common must be Reference to Earth ground to prevent surging and a path for over current. Over current can occur especially with inductive loads such as electric motors. Poor house grounding is one of the leading causes of home electrical fires. Installing fancy outlet will not solve your problems. Have your wiring checked by a professional electrician.

author: themadhippy
author_rank: Super Contributor
timestamp: April 02, 2025, 10:00:24 am
content: Quoteno it musn't,if that was the case how would overload protection work on an isolated supply?and why dont the voltage surge on such supplies.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 02, 2025, 10:03:23 am
content: Quote from: floobydust on March 29, 2025, 07:01:00 pmI think the side that burned is Neutral not Line.

author: Jwillis
author_rank: Super Contributor
timestamp: April 02, 2025, 11:09:59 am
content: Quote from: themadhippy on April 02, 2025, 10:00:24 amBecause the primary of your isolated supply is reference to ground.

author: tszaboo
author_rank: Super Contributor
timestamp: April 02, 2025, 11:45:34 am
content: Quote from: bdunham7 on March 31, 2025, 08:48:57 pmRight, so if the breaker is 20A, then the outlet should be able 20A, and it doesn't.EU, 16A outlets are used with 16A breakers.I also wouldn't leave it to the outlets, something that people often exchange themselves to determine the rating. Sounds like common sense. I just checked the website of the local DIY shop, you can only buy 3 type of sockets here:- Type F Schuko with earth- Type F Schuko without earth, which is not a valid installation since probably 30 years. IMHO a house shouldn't be called habitable without earthed outlets.- Some abomination that they did for the heating systems, because no rules i guessNone of the outlets are rated for more than or less than 16A.

author: themadhippy
author_rank: Super Contributor
timestamp: April 02, 2025, 11:55:30 am
content: QuoteAnd on a standalone generator with no connection whatsoever to ground? If a ground is needed for overload protection how do they work on a battery supply?

author: Berni
author_rank: Super Contributor
timestamp: April 02, 2025, 01:09:46 pm
content: Allowing a 15A rated outlet on a 20A breaker does sound like a bad idea indeed.Extension cords with multiple outlets are a thing, so a user can quite quickly unknowingly overload a outlet to 20A and not have the breaker trip.Tho UK outlets like to do a similar thing, but they are counting on the mandatory fuse in the plug to protect from this, so if you tried to abuse an extension cord in such a way, then the fuse in the extension cords plug would blow.As for the US switching to 220V, there is not that much benefit. They already have split phase 110V and if you have a similar amount of load on both phases that does act like it was a big 220V load across the two phases (neutral conductor current becomes near 0). They just need some standardized high power socket to let them plug regular appliances like kettles into the more spicy 220V between phases.

author: themadhippy
author_rank: Super Contributor
timestamp: April 02, 2025, 01:57:02 pm
content: And yet in europe no one seems concerned the 1mm flex on there plug going to a 6A iec is only protected by a 16A device.

author: MrAl
author_rank: Super Contributor
timestamp: April 02, 2025, 01:58:23 pm
content: Quote from: Monkeh on April 01, 2025, 01:55:22 pmHi,Yes, there are loads that already work at 230vac (or if you want to call it 240vac).What would probably have to happen in order to see the benefits I was talking about is ALL the power line voltages would have to double, even the high tension wires. That's also probably very hard to do because of the spacing requirements. So it's probably impossible to get any benefit without a lot of modifications. Maybe the only solution is to run more wires in order to carry more current.

author: Langdon
author_rank: Frequent Contributor
timestamp: April 02, 2025, 02:01:43 pm
content: In theory, EU plugs are great, but they are so unstandardised they end up being terrible.The main problem with US plugs is the ground prong always breaks first, leading to ungrounded equipment, which is unsafe.The line prong should always be machanically weakest!Not the ground!The ground prong should be the most mehanically robust, not the least!

author: MrAl
author_rank: Super Contributor
timestamp: April 02, 2025, 02:07:27 pm
content: Quote from: tooki on April 02, 2025, 05:53:30 amYes, but I mentioned the higher voltage lines too because they would have to double in order to see the benefit, and I don't think that would be easy to do. All the voltages coming into the home would then be 230vac, on both sides of neutral. So each house would have a minimum of two 230vac lines coming into the house from the pole.This is probably just too hard to achieve for large areas across multiple states.Inside the home it would increase the power capacity of every line that was not already using 230vac. Around here #14 AWG wire is considered ok to handle up to 15 amps, but that would double if it was to carry 230vac instead of 115vac (or 240vac and 120vac). Of course we'd also have to consider spacing with twice the voltage.

author: themadhippy
author_rank: Super Contributor
timestamp: April 02, 2025, 02:11:15 pm
content: QuoteNo it wouldnt,the HV side of things can stay exactly as it is,its just the transformers to users that would need a tweakQuoteGranted a vast improvement on the us plug,but great?,even the far superior uk plug has its flaws,as you soon discover when you stand on one in the middle of the night.

author: Langdon
author_rank: Frequent Contributor
timestamp: April 02, 2025, 02:31:14 pm
content: Oooh.That's gotta hurt!On a second thought, plugs should be kinda flat.Also, when voltage is doubled, the power consumption of most things actually quadruples!For example, the initial inrush current of an SMPS is proportional to voltage.At 110V, it is usually around 30A, at 220V, it is 60A!

author: Jwillis
author_rank: Super Contributor
timestamp: April 02, 2025, 08:19:48 pm
content: Quote from: themadhippy on April 02, 2025, 11:55:30 amStand alone portable generators Are recommended to be Earth grounded. Check the manual. If you look at any portable generator sold in North America, there will be a point labelled to connect an Earth grounding rod. When connecting a portable generator to a house panel, such in the case of emergency back up systems, the generator is grounded through the panel. In such a case you don't ground the generator because that causes ground looping.Small portable generators may have at most 100 feet of extension cord. A house can have several hundred feet of wiring. This wiring can build static electricity . This is due to the parasitic capacitance and inductance of all that wiring in your home. Your measurement from line to common can read 120V or 240V depending on service, but between a floating system and earth the potential can reach several hundred volts higher. So when connecting something to the circuit this causes a sudden discharge that can damage equipment and can even cause arcing inside the receptical.Advising people that a local Earth ground reference to common is not necessary is stupid and dangerous.

author: themadhippy
author_rank: Super Contributor
timestamp: April 02, 2025, 08:42:04 pm
content: Quoteeven on an IT arrangement?Quotewere did i say that? My question was for you to explain why you think an overload device needs the circuit referenced to ground for it to operate.

author: TimFox
author_rank: Super Contributor
timestamp: April 02, 2025, 08:43:46 pm
content: Quote from: MrAl on April 02, 2025, 02:07:27 pmInside my typical modest house in Chicago, USA.Three wires come from the pole transformer to my house and two neighbors: normal US-style split phase 240 V center-tapped with neutral wire at center tap. The circuit breaker box has appropriate bus bars for connecting the breakers. Most are for 120 V, with 14AWG wires from 15 A breakers and 12AWG from 20 A breakers. The box can also hold 2-pole (companion-trip) breakers for 240 V loads.In my particular case there are only two 2-pole breakers: one for the central air-conditioner and another for a surge suppressor on the side of the box, but the box could be re-configured for more 2-pole and fewer 1-pole breakers.What advantage would I have for changing over to 240 V, unless I were to change from gas to electric stove?

author: Jwillis
author_rank: Super Contributor
timestamp: April 02, 2025, 11:18:03 pm
content: Quote from: themadhippy on April 02, 2025, 08:42:04 pmMy original comment for the reason of the OPs problem.Which I explained.You chose to cherry pick a piece of that comment to create an argument'From your reply post, and I quote:"no it musn't,if that was the case how would overload protection work on an isolated supply?and why dont the voltage surge on such supplies."That is a direct suggestion that ground referencing the common is not required. Even polarized plugs are ground referenced.Ground connection serves 2 main purposes. Holding Common to as close as possible to zero volts.This keeps the voltage stable on the live lines. I've already explained why. Second is to provide a path for over current and over voltage situations. Which I explained.It is you that chooses to cherry pick pieces from a comment and diverge from the original point of the thread.If people cant read the context of comment in its entirety that's not my problem.

author: Monkeh
author_rank: Super Contributor
timestamp: April 02, 2025, 11:29:57 pm
content: Quote from: Jwillis on April 02, 2025, 11:18:03 pmWhere?How and why does an overcurrent situation cause current to flow in a ground wire? Same for overvoltage, actually..

author: TimFox
author_rank: Super Contributor
timestamp: April 02, 2025, 11:33:14 pm
content: Should a live (hot) wire inside an appliance short to the metal case, if that case is properly grounded to PE and the neutral is properly connected, then the circuit breaker should open on that circuit.If the metal case is not grounded, or connected to only two terminals of an AC feed, but the power line neutral is properly grounded, then you could have a dangerous voltage between the case and your plumbing.

author: themadhippy
author_rank: Super Contributor
timestamp: April 03, 2025, 12:07:06 am
content: Quotewhich in my opinion is utter rubbish,the problem is a bad connection between plug and socket that no amount of earthing would cure,and as for your claim that an earth is required as a path for over current,the only time that would be an issue is with a fault between phase and earth,a phase to phase or phase to neutral fault couldn't care less what the earth is doing.

author: Jwillis
author_rank: Super Contributor
timestamp: April 03, 2025, 01:50:41 am
content: Quote from: themadhippy on April 03, 2025, 12:07:06 amEvery thing I stated s fact. I deal with these sorts of issues on a regular basis. You obviously haven't a clue about mains voltages or safe use of its application. Nor the correct safety requirements. So go back to your arduinos and IT equipment and leave the high voltage to people who know what they're doing before you burn down someones house or get someone killed. End of discussion with you.

author: Berni
author_rank: Super Contributor
timestamp: April 03, 2025, 05:25:56 am
content: Quote from: Jwillis on April 03, 2025, 01:50:41 amThe problem is that a lot of your claims don't make sense with the lays of physics, let alone electrical code.Pretty much none of the overcurent protection devices seen in mains wiring even have a connection to the PE conductor. So there is no way they could 'divert overcurent to earth' since there is no wire connected to carry current in that direction.An exception are surge protectors, these do have a PE connection. This is because they are mainly designed to snub out fast brief overvoltage events caused by lightning strike and similar. These happen too quickly for the 50/60 Hz transformer in the street to eat up and even happen too quickly to even transmit over mains wiring due to the stray inductance of the wires. So as a result you can have hazardous voltages develop even within the house wiring. This includes the wire for N to PE bonding, so to be sure they place transient voltage suppressors across all 3 wires, this way the electrical appliance would never see any voltage outside of what it was designed for (within sensible limits, lightning can be very powerful).Broken ground connections are mainly a shock hazard for people using appliances, but they don't make stuff catch fire. What is dangerous to appliances is losing a neutral in a multiplhase system. This can cause neutral to float off towards one of the phases and suddenly give up to 220V in outlets that are supposed to only be 110V (Or here in EU you could get up to 400V on a wall outlet for 230V)

author: tooki
author_rank: Super Contributor
timestamp: April 03, 2025, 09:04:35 am
content: Quote from: Langdon on April 02, 2025, 02:01:43 pmIn 40+ years of using US plugs, I’ve never had a prong break off. It’d take tremendous abuse to cause that. (The plugs made of folded brass are definitely less robust than the solid types that are prevalent today. In the folded brass types, the flat blades are just very easy to bend.)

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 03, 2025, 09:11:27 am
content: Quote from: themadhippy on April 03, 2025, 12:07:06 amYes it would be an electrical shock hazard but it's not an overload situation and would not cause anything to burn out.

author: Langdon
author_rank: Frequent Contributor
timestamp: April 03, 2025, 12:47:22 pm
content: The grounding prong is generally made of brass sheet metal.It is usually not solid for some reason.

author: Jwillis
author_rank: Super Contributor
timestamp: April 03, 2025, 01:44:17 pm
content: Quote from: Berni on April 03, 2025, 05:25:56 amThe laws of physics do apply. In a fully floating AC circuit without grounding, static electricity builds up. This build up of static occurs more when the theirs a lot of wiring such as in a home . The common is not reference to ground to hold it to Zero volts. The wires built up static that has no place to go. So it continues to build to potentials of hundreds to even thousands of volts. Plug something into the wall socket. In an instant the circuit is now complete allowing the static to move from a high negative potential to a low negative potential. DC can carry AC. The AC has a current potential as much as the service allows. DC static arc carries AC current in an instant. The highest potential resistance is in the plug. So imagine you have 1000 volts potential static build up on your wire with at least 15A of current available. That's 15000 watts of energy that needs to be dissipated instantly. The potential energy can be even more because there may be 100's of amps available and potentially thousands of volts of static electricity. The plug is the weakest point with the highest resistance where heat builds instantly. The heat in the plug melts plastic, and combusts any flammable material present causing a fire.Electricity moves from highest potential to lowest potential. There can be no Current if the is no Voltage. There can be no Voltage without current. So Yes, Current can pass to Earth when there is a Voltage potential difference.

author: MrAl
author_rank: Super Contributor
timestamp: April 03, 2025, 01:49:51 pm
content: Quote from: TimFox on April 02, 2025, 08:43:46 pmHi there,Well, first consider the portable drill. These are the drills that run on rechargeable batteries either NiCd, NiMH, or Lithium Ion in most of them that most people have.When they first appeared on the market, they were 3v which was two NiCd's in series. These had some power though because the chuck was geared down. I had one of the first ones and I really liked it, but it was really an electric screwdriver. I converted it into a drill by making a chuck with a stem that could be inserted into the screwdriver chuck. It worked pretty well although the rotation speed was fairly slow. I used it for a couple years I think.Anyway, after that the voltage starting going up. 3v to 6v to 9v to 12v to 15v to 18v to 21v to 24v, and still going up. Why would they go up in voltage. That was to increase the available power to the motor and thus get a stronger drill torque to do all kinds of things, as well as a possible higher speed for drilling.That's like the prototype for this idea of increasing voltage at the home outlet or similar.For your situation, if you could convert everything in your home to 240vac (I will use 240 because you did although some people call it 230) that would mean your #14 AWG wire that can handle 15 amps can still handle 15 amps, but now at 240vac up from 120vac there is an obvious advantage: you could get either twice the power from the outlet, or if you do not need the added power then you could run at 1/2 the current. If you had something that really did draw 14 amp at 120v, then at 240v it would only need 7 amps. That also means that every wire in your house could handle the current in that way. If the breakers could handle 240vac up from 120vac then you would not have to change them, but if they couldn't you'd have to change them too.Granted, this kind of upgrade would not be super easy because ideally we'd have to change all of our appliances to run on voltages common in Europe, and that would mean, ideally, buying all new appliances. We could use step down transformers I guess, but it would be better to buy new appliances. If you have something that runs at 240vac already, you probably would not have to change that unless you wanted to go to 480vac which I'll get to next.The next change would be from the pole to the house. If you get split 240vac at 100 amps that's 24kWatts. With an upgrade to 480vac at 100 amps (same wire possibly) that's 48kwatts. With the advent of electric vehicles, that could be a big advantage not only for homes but for charging stations, businesses, etc.Now at the pole, the line voltage should go up too. If it is 5kvolts then it should go up to 10kvolts.Going farther upstream, that might go up to 50kvolts which would then have to go to 100kvolts, and farther upstream 400kv up to 800kv.Unfortunately, the bottleneck would be at the generator station. I don't think it would be able to double the power output without extensive upgrades. However, everything downstream would become more efficient if the allowed power stayed the same because the current would be halved everywhere. That means less loss in the wiring all the way.This would take a lot of thought though, and agreements between a lot of power stations and electric companies and whatnot, so I don't see it happening unless it becomes absolutely necessary and there are no other inventions that can do better before then. It's a sort of pipedream, a mind experiment to some degree. We do have a lot of innovation coming up these days though. There is a chance it might help with the home though with the wiring from the pole to the house and the wiring inside the house.

author: MrAl
author_rank: Super Contributor
timestamp: April 03, 2025, 01:58:08 pm
content: Quote from: tooki on April 03, 2025, 09:04:35 amHi,I had the ground prong break off of one device I had, that was a Kill-O-Watt power meter. That was the only one I can remember in many years.The problem with some of them is that the prong itself is made really well, but at the base sometimes there is a very narrow section that connects the prong to the electrical connection inside and that can break. For this meter it was a little too cheaply made so one day when it was unplugged, the prong stayed inside the outlet hole.It is still useable though as long as I don't really need the ground connection because the two power prongs are still just fine.That's the only time I've seen this happen though that I could remember.

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 02:37:59 pm
content: Quote from: MrAl on April 03, 2025, 01:49:51 pmI see no advantage to the change, but a lot of expense.US voltage is 240/120, and has been for a long time.Perhaps if I needed to import an infamous UK teakettle, which requires 240 V, I could get a 240 V outlet installed in my kitchen, connecting to my existing circuit-breaker box, without replacing every normal appliance, including my power drills.

author: tooki
author_rank: Super Contributor
timestamp: April 04, 2025, 08:54:38 am
content: Quote from: MrAl on April 03, 2025, 01:49:51 pmAll of this assumes that utilities didn’t already consider the balance of factors in determining the voltages of the distribution grid when they designed it, and it also assumes that the grid is capacity-constrained right now.To be clear: current dictates how thick the wire must be (for a specified level of acceptable self-heating and voltage drop), while voltage dictates what the insulation and clearances need to withstand.Doubling the voltages would require significantly redesigning the entire distribution grid to handle the higher voltages. You couldn’t just increase voltage, you’d need to replace most of the infrastructure.If the grid is currently capable of handling its needs, then increasing its capacity at great cost and effort is just money flushed down the drain.Quote from: MrAl on April 03, 2025, 01:49:51 pmYa think!??!I mean… do you even realize that generators do not generate at multi-hundred kV, but that the voltage is steppedupusing transformers? High voltage is a bitch to work with (things that are insulators at 1000V suddenly aren’t when you’re dealing with 50kV), so you avoid it where possible. That’s why we don’t deliver 400kV to your street.So to double the output, you’d just need to double the plant’s generating capacity. That’s not a magic switch you flip, that’s literally just building more power plants.

author: MrAl
author_rank: Super Contributor
timestamp: April 04, 2025, 11:49:40 am
content: Quote from: TimFox on April 03, 2025, 02:37:59 pmHello again,I knew you did not see any advantage to this when I wrote thatHalf the current in every wire in the house or twice the power delivery through every wire in the house means nothing to you, and that's without changing any wiring in the house.

author: MrAl
author_rank: Super Contributor
timestamp: April 04, 2025, 12:04:01 pm
content: Quote from: tooki on April 04, 2025, 08:54:38 amHello again,Everything you just said I already said so I am not sure why you are restating it as if you are telling me something new.I already stated the problems that would have to be mitigated and that they would not be easy to do. The main point is that an increase in voltage means less loss in the wiring, or an increase in power delivery. This is common knowledge.Engineers seldom settle for old school designs. New standards come up all the time and they help to reduce energy losses and the like. Innovation is always on the horizon. With the grid this could be traced back to the 110v to 115v to 120v evolution, so this would not be entirely new just more extreme. And yes, more costly, but that did not stop the Webb Telescope nor other great projects of the day. It depends on what the demands are and what they become.The grid in the USA is facing some problems that will eventually have to be overcome. There are even worse problems that nobody is doing anything about that could lead to a catastrophe in the future. If you don't agree with that then you must not live in the USA.Maybe we should tell everyone in Europe to downgrade to 120vac like in the USA since there is no advantage, according to someIt's ok if you don't agree, I have no problem with that, but please come up with some ideas that have not already been pointed out.Also, is this actually going to happen? Anything like this would have to be funded by the government and right now they don't like funding anything, so relax

author: Berni
author_rank: Super Contributor
timestamp: April 04, 2025, 12:50:48 pm
content: The EU and US power grids are not all that different.The grid itself is all 3 phase AC (apart from a few DC links) running at whatever number of kV the transformers on that transmission line are designed for. There is no point in messing with the voltage there, doubling the voltage would mean changing out all of those giant transformers, switchgear and insulators on lines.Industry handles mains power the same in US as in EU. They get a big high voltage 3 phase feed (say 20kV or so) coming into the property and then they step that down to AC of whatever voltage they need for the machines, some are 110V some 220V some 400V some 600V some 5000V..etcThe main difference is how AC power is distributed to residential customers. In EU we typically bring in delta 3 phase AC (~20kV) into a residential area, then have a hefty car sized transformer turn that into Y 3 phase AC at 230V per phase. Then we run that low voltage 3 phase out over the streets, bringing all 3 phase into a house where the loads then go between L and N (tho some counties have loads between phases, ie Norway). This cuts down on the number of transformers and copper gauge going into houses.In the US they bring Y 3 phase (likely ~5kV to ~30kV) into an residential area, then run 1 phase down each street. Every so often they hang a smaller garbage bin sized transformer on a pole to take high voltage single phase and produce 110V split phase. This is then run into houses to get you 110V per phase or 220V between phase. The house can then place loads on L-N for 110V or L1-L2 for 220V. This uses more transformers but reduces the number of wires needed and keeps things high voltage for more of the journey.Both of these systems are just fine, it all works out as the same thing at the grid level, the residential area as a whole is one huge ~20kV 3 phase AC load. The difference is just that the wiring inside a US houses uses up more a bit more copper because the 3 phase system ends earlier along the way (and so some of the benefits of 3 phase are lost)

author: TimFox
author_rank: Super Contributor
timestamp: April 04, 2025, 02:29:19 pm
content: @Mr Al:"I knew you did not see any advantage to this when I wrote thatHalf the current in every wire in the house or twice the power delivery through every wire in the house means nothing to you, and that's without changing any wiring in the house."You are correct. With the exception of computer, television, and battery chargers all of my appliances (except the air conditioner) will only work with 120 V, and the existing wiring is adequate. What would be my return on investment for changing all of the outlets and buying a new set of appliances (refrigerator, laundry machines, etc.)?By the way, in Chicago the electrical utility is in the slow process of changing high-voltage distribution to pole transformers, etc. from the existing 4,000 V to 12,000 V (primary).Their wires are much longer than those inside my house.

author: MrAl
author_rank: Super Contributor
timestamp: April 04, 2025, 06:41:26 pm
content: Quote from: TimFox on April 04, 2025, 02:29:19 pmHi,But if you did not have all outlets changed to 240vac, how would you be able to power your little 1 watt LED night light? (ha ha)Yes that's a good point about the computer and stuff like that (and the pun with the night light).My original thoughts were for improvement with the grid itself because of the problems we are having in various reasons with planned blackouts, etc. Someone I knew well who recently moved to Los Angeles has to put up with that. I would love to have it in my house too though because there would not be so much of a voltage drop (we have some long lines in this house).So the benefits would be for some people not as much for other people when it comes to what appliances they are running, although improvements to the grid would eventually benefit everyone. Granted, again, that would not be easy, and require a lot of planning as well as funding, but something has to be done or we all get in trouble.It's nice to hear your area is already doing some of this (upping the voltage) since that is part of the USA I am happy to hear someone is doing something already. I hope that hits my area soon too. I seriously doubt they would convert to the European standard though, and have us all buy new high current devices like space heaters. I'd jump right on board, but I also realize this would be hard for some people.I have a feeling you would be totally against going to all DC transmission then

author: MrAl
author_rank: Super Contributor
timestamp: April 04, 2025, 06:54:26 pm
content: Quote from: Berni on April 04, 2025, 12:50:48 pmHi,That's very interesting thanks for sharing.I would love to have 3 phase in here but I think that's a lot more expensive around here. Back when I worked in the power control industry, we had 3 phase coming into the building but that was a necessity because some of the equipment we made was 3 phase, mostly 240vac 3 phase.From time to time I also hear about going to some DC lines too and using power converters instead of transformers. Seems kind of crazy until we look at the losses due to skin effect. With DC there is no skin effect. I doubt Edison was aware of that or that could have been a selling point for his pro DC arguments. For me, I'd love to have 5v DC coming into the house from the pole (ha ha) and maybe eliminate all these dang wall warts. Ultimately 5v, 9v, 12v, 15v, 18v, 21v, etc., would be amazing to see. Doesn't make sense though of course, would be better to just run AC and then convert it in the house with a larger converter that could power all the cell phones and laptops and you name it. One converter for everything.I have a feeling thoughts like these are going to come up more as time goes on with the problems with the grid and with charging everything from cell phones to electric vehicles.What the best solutions are I am not sure of just yet.I read about a massive power failure a long time ago that took out all the lights in New York (probably the city). The failures went in a chain reaction as each generator shut down to protect itself, the next available generator on the grid took over but then also had to shut down, and this went on for several generators until one in New York decided to try to power the entire downed part of the grid, and 10 minutes later the generators were damaged. Pretty nutty to try to do that I think as there is automatic shut down to protect the generators so that should not be overridden.

author: TimFox
author_rank: Super Contributor
timestamp: April 04, 2025, 07:00:57 pm
content: Quote from: MrAl on April 04, 2025, 06:41:26 pmIncreasing the voltage on the long wires from Commonwealth Edison to my local transformer will result in some improvement of efficiency.Given my normal domestic use of 120 V inside my house, what increase in efficiency would you anticipate?What change in electrical safety would you anticipate when increasing the local voltage from 120 to 240 V?A typical pair of 14 AWG wires from the breaker box to a downstairs floor outlet might be 25 feet (each of two wires). The resistance of 50 feet of AWG 14 is 0.126\$\Omega\$, or 1.9 V at 15 A (breaker rating). The typical load on one such outlet is less than 4 A (480 W), with modern lights and appliances, or about 0.5 V (0.4% power loss).Big deal!

author: tooki
author_rank: Super Contributor
timestamp: April 04, 2025, 07:12:53 pm
content: Quote from: MrAl on April 04, 2025, 12:04:01 pmit doesn't sound to me like youreallydo understand it all.Quote from: MrAl on April 04, 2025, 12:04:01 pmCorrect. But that is far from the only factor to be considered when designing a grid.Quote from: MrAl on April 04, 2025, 12:04:01 pmThere's nothing to innovate here. Doubling the consumer line voltage changes nothing on the grid, as the grid voltages are alreadynot120/240V. The grid voltage can be, and is, chosen and changed according to actual needs.Quote from: MrAl on April 04, 2025, 12:04:01 pmSure. But whether the consumer gets 120V or 240V service is neither here nor there.Quote from: MrAl on April 04, 2025, 12:04:01 pmNo, you were told it had "no advantage" because you kept moving the target. There is, indeed, no significant advantage in raising the grid voltage of a system that is not at capacity. (And again, the consumer voltage is independent of that.) The advantage would have to behugeto justify the massive expense of changing the grid voltages.Quote from: MrAl on April 04, 2025, 12:04:01 pmI'm not trying to come up with ideas. I'm just telling you your idea is silly and belies incomplete knowledge.

author: tooki
author_rank: Super Contributor
timestamp: April 04, 2025, 07:14:05 pm
content: Quote from: Berni on April 04, 2025, 12:50:48 pmFor the umpteenth time:USA is 120/240V.Not 115/230V, not 110/220V. It used to be, but hasn't been for a very, very long time.

author: TimFox
author_rank: Super Contributor
timestamp: April 04, 2025, 07:35:35 pm
content: More numbers and math, related to a possible investment in changing my house outlets from 120 V to 240 V.My electricity bill for 24 February through 26 March (30 days), when my air conditioning (which uses 240 V split-phase) was not running, was for 430 kWh for that month.The bill separates supply, delivery, and taxes.Most of these line items are proportional to the kWh consumed, at about $0.15 / kWh total, plus a fixed charge of $19.58 / month and about $7.40 / month in taxes and fees (total $89.28).If I saved 1% of the 430 kWh (a generous estimate), or 4.3 kWh, the reduction in cost would be about $0.65 / month = $7.75 / year.If I financed the changes in my internal wiring at, say, 5% per annum interest, I could only afford a changeover price of $155.I am just powering a modest, middle-class, single-family house in a large city: I don't run an aluminum smelting plant.Math is hard, but this does not require an accounting degree: engineering does require knowledge of ROI.In summer, the air conditioner does increase the power consumption, but that is already wired for 240 V.Converting to DC at my house is even less attractive.

author: MrAl
author_rank: Super Contributor
timestamp: April 05, 2025, 12:29:10 pm
content: Quote from: TimFox on April 04, 2025, 07:00:57 pmNow multiply that by about a zillion and a half and you will see the effects over the entire grid.For the individual house, if every outlet was 240vac then the increase in efficiency would depend on the length of wire. Since the wire would be handling half the current, the voltage drop would be half. Is that significant? It depends on how much wiring is in the target house, and how much current is drawn. For some people it may not make too much difference, for others it would.Imagine how many miles of wiring there must be in the US and Canada grid. A million miles?Then the energy generation, maybe 4.2e12 kilowatt hours. Every hour that's 4.2e12 kW.That's a lot different than one person's house.I'm not sure what else to say because if it does not matter to you if the voltage is doubled, then it does not matter to you. There is nothing on earth that will change your mind I don't think because from your viewpoint there is no difference, or little difference.

author: MrAl
author_rank: Super Contributor
timestamp: April 05, 2025, 12:38:37 pm
content: Quote from: tooki on April 04, 2025, 07:12:53 pmHello again,If it is silly, then why is it being done in some areas already?Engineering is not about saying "no" to everything. It's about innovation, and that is the ultimate concern when there is a genuine NEED to innovate. If you don't like the idea, then why don't you come up with a new one, more sensible to you? I'd be happy to hear about it, really. This is an important issue in the US right now.I'll say to you what I said before here...START QUOTEImagine how many miles of wiring there must be in the US and Canada grid. A million miles?Then the energy generation, maybe 4.2e12 kilowatt hours. Every hour that's 4.2e12 kW.That's a lot different than one person's house.I'm not sure what else to say because if it does not matter to you if the voltage is doubled, then it does not matter to you. There is nothing on earth that will change your mind I don't think because from your viewpoint there is no difference, or little difference.END QUOTEHowever, I'm still very open to hearing your ideas and suggestions for improving the grid. I'd certainly consider any new idea no problem. If that idea is better than mine, that's entirely fine with me. Right now almost anything is better than nothingI also appreciate your contribution to this.

author: tooki
author_rank: Super Contributor
timestamp: April 05, 2025, 01:47:04 pm
content: Quote from: MrAl on April 05, 2025, 12:38:37 pmIf you actually read what I wrotecarefully, you'd see that I did not say it is NEVER worthwhile.I said (bold added now):Quote from: tooki on April 04, 2025, 07:12:53 pmSo yes, there are circumstances where it makes sense to do so. And in those cases, it is done.It's also conceivable that it is done if an entire area already needs to be refurbished due to age (i.e. "If we have to replace everything anyway, we may as well upgrade it.")It does not make sense to do everywhere.

author: TimFox
author_rank: Super Contributor
timestamp: April 05, 2025, 03:43:57 pm
content: @Mr AlYour idea of engineering, that totally ignores costs, is misguided.With respect to my house, which you insist I re-wire for a very small reduction in distribution loss within my property, my example of 430 kWh per 30 days is about 600 W average power over that month.My example calculations above gave an exaggerated loss of 1% power due to the wiring between entrance and load, or about 6 W.Engineering calculations must not ignore capital cost; thecurrencyof the United States is the dollar, not the kWh.If I want to spend money to reduce my power consumption, it would be better spent on replacing my refrigerator with a more efficient model.Meanwhile, Commonwealth Edison is considering the cost and benefit of increasing their supply voltage from 4 kV to 12 kV over their long wires.Regardless of my domestic wiring, this will require capital investment in new transformers and insulators on their distribution system, not a magic wand.

author: MrAl
author_rank: Super Contributor
timestamp: April 06, 2025, 03:48:33 pm
content: Quote from: tooki on April 05, 2025, 01:47:04 pmSo I guess you are onboard now, but if not everywhere then MOSTLY everywhere I would think.

author: MrAl
author_rank: Super Contributor
timestamp: April 06, 2025, 03:55:28 pm
content: Quote from: TimFox on April 05, 2025, 03:43:57 pmIt sounds like you are just repeating what you said before, and I partly agreed. For this discussion your house or my house taken alone is insignificant.I also said it would not be easy and I also mentioned that it would have to be funded probably by the government.If they do not raise the voltage, then they have to double up on the wire runs. Either that or they have to find a way to get consumers energy use down, maybe by doing some R&D on the big appliances like air conditioners. Not sure if that would be enough though.Of course more energy generation is always on the table, and another solution may end up being miniature local nuclear power generators which seem to be on the table now. That would help the grid too because then the wire runs would be shorter, at least locally, and no need for long high voltage wire runs (hopefully)

author: TimFox
author_rank: Super Contributor
timestamp: April 06, 2025, 04:11:03 pm
content: Quote from: MrAl on April 06, 2025, 03:55:28 pmAs I keep repeating, despite your strange un-quantitative replies, raising the distribution voltage from 4 kV to 12 kV, as Commonwealth Edison is starting to do, makes perfect sense.But why do you think this has anything to do with the internal distribution in my house at 120/240 V?The 120/240 V wires from Edison's pole transformer to my meter and breaker box are a measly 50 feet or so, with appropriate wire gauge. I don't know how long the 4 kV wire from the nearest substation is, but my guess is about 2000 to 5000 feet. That substation, in turn, is fed from a much higher voltage from more distant power plants.The discussion of power distribution within a building or customer property is very important for high-power loads, such as aluminum plants or data centers, and reasonably-high power loads such as factories or office buildings.This is why I agreed with your statement above, "Half the current in every wire in the house or twice the power delivery through every wire in the house means nothing to you, and that's without changing any wiring in the house."Since I can do the math, that statement means nothing to me. My house is limited to 100 A at 240 V by the incoming circuit breaker, and I don't use very much of that, except for the air conditioner that is already wired for 240 V.Skin effect in 50/60 Hz wiring smaller than 1 cm diameter is negligible.Higher current distribution in large facilities is usually done with rectangular bus bars, to avoid skin effect, once you get to wire size requirements larger than 500 mcm (23 mm diameter).Everything I have posted here as a response to your posts on this topic is a refutation of your statement:"I'd love to see the US switch to 230vac rather than 120vac (or 115vac as it is sometimes called), along with the required outlet type to go with that.For one thing, an appliance at 230vac only has to draw one-half of the current as a 115vac device has to draw in order to run at the same power level.That would achieve a lot, the first being it would reduce the stress on the power grid with only 1/2 of the current flowing through all the wires on the low voltage side (probably the very high voltage side would have to stay the same)."This comment is a total misunderstanding of power distribution: Commonwealth Edison and other US utility companies do not distribute power at 120/240 V (or 120/208, etc., for three-phase distribution) over their distribution lines.The distribution lines (at high voltage, such as 4 kV) go to customers' property through local transformers.

author: Jeroen3
author_rank: Super Contributor
timestamp: April 06, 2025, 07:55:35 pm
content: One of you is trolling.

author: TimFox
author_rank: Super Contributor
timestamp: April 06, 2025, 08:07:43 pm
content: Not I, said the fox.

author: tooki
author_rank: Super Contributor
timestamp: April 07, 2025, 11:49:46 am
content: Quote from: MrAl on April 06, 2025, 03:48:33 pmUh, no. DO NOT put words in my mouth.I still think it doesn’t make sense most of the time — as evidenced by the fact that utilities don’t do it everywhere. They invest in upgrades where it makes sense, and not where it makes no sense.

author: MrAl
author_rank: Super Contributor
timestamp: April 07, 2025, 03:42:14 pm
content: Hello again,Ok, it appears that some of us are not going to agree on some points ever, so I guess it is time to give this a rest for a while.To everyone who participated, good luck with your wiring, in house or outside or down the street or at the power station or whatever

author: tooki
author_rank: Super Contributor
timestamp: April 07, 2025, 04:49:58 pm
content: Quote from: TimFox on April 06, 2025, 04:11:03 pmExactly this. I explained the same thing early on, too. Since then he keeps moving the target since his actual original premise was predicated on nonsense.

author: Teledog
author_rank: Regular Contributor
timestamp: April 08, 2025, 01:06:13 am
content: I like the option of 120/240 in the kitchen. (commercial appliances)Put in a special receptacle/outlet for it. (good old Amazon).

author: MrAl
author_rank: Super Contributor
timestamp: April 08, 2025, 10:39:48 am
content: Quote from: Teledog on April 08, 2025, 01:06:13 amHello there,Thanks for joining the discussion.It's amazing what we can do when we don't rely on old standards and procedures. I see those outlets also in Home Depot. Leviton makes at least three different models that I've seen so far.What I had been thinking was also about improving the entire grid BEFORE we end up with bigger problems. We might have to wait a bit for that though I'm afraid.I happen to live in a problem area so I have seen what problems can come up with the power lines. We get some pretty deep drops in voltage during the summer.

author: Stray Electron
author_rank: Super Contributor
timestamp: April 08, 2025, 08:30:32 pm
content: Quote from: Teledog on April 08, 2025, 01:06:13 amYeah I like that idea too but it would require a special circuit breaker and one extra conductor in the power line so no contractor/home builder is going to install it willingly. Also I've seen very few kitchen appliances in the US that could run on 220VAC. I know that they're offered in other countries so they are available but they would require a US certification and they would need to be able to run on 60 Hz.I have a good amount of 220V power tools and even some 220V TE and I keep a fair size 110V to 220V transformer based converter handy. Fortunately all of my 220V stuff only requires a few amps so a 15 Amp 110 V circuit can supply enough power.But my wife would not appreciate the art work!

author: Teledog
author_rank: Regular Contributor
timestamp: April 09, 2025, 12:24:24 am
content: Most of Canadian (and I'm sure US) electrical code in the past X years is to have "staggered" breakers in the kitchen.It's to prevent breakers blowing if one has, say a kettle and a toaster on the same outlet. (typically 15A each)Easy check - measure your "hot to hot" upper & lower outlet with a meter, if it shows 240, bingo! Separate breakers!If one removes the outlet cover & drags out the outlet (shut off your kitchen breakers please- safety here!), if the tab is broken off between the outlets, it's staggered.We have three separate staggered 15A breakers for the (oops) 5 outlets to our kitchen.Wiring into the house is two hot & one neutral ..120x 2 - for 240 to stove, dryer, etc.G'luck!

author: incf
author_rank: Frequent Contributor
timestamp: April 09, 2025, 12:39:28 am
content: Quote from: Teledog on April 09, 2025, 12:24:24 am(joking) So all we need is a new plug! Like the dual banana plugs for test equipment.I've come to the opinion that a standard outlet would require8 thermal fusesto be melt proof. (Line/Neutral, DaisyChainIn/DaisyChainOut/Socket1/Socket2)It seems more understandable now why it isn't a thing.If the manufacturers can't be bothered with simple issues like having multiple points of contact (or whatever is required) on "backstab" connections - then they certainly can't be bothered with anything more complex.I suppose the handful (dozens? hundreds? thousands?) of melted outlets a year are just a cost of doing business.

author: Teledog
author_rank: Regular Contributor
timestamp: April 09, 2025, 12:48:23 am
content: Not going to argue, but the original pics look like;A: a defective outletB: too much current draw from a devicePS:Have you checked your breakers ie: tested? flipped them back & forth? They DO fail Fused contacts or otherwise!

author: MrAl
author_rank: Super Contributor
timestamp: April 09, 2025, 12:11:13 pm
content: Quote from: Teledog on April 09, 2025, 12:48:23 amHi,Yeah there has to be more to it, I've never seen one THAT bad before this.

author: TimFox
author_rank: Super Contributor
timestamp: April 09, 2025, 03:09:35 pm
content: Quote from: MrAl on April 08, 2025, 10:39:48 amAgain, thegridis not 120/240 V: it is connecting and distributed at far higher voltage by companies that know what they’re doing.

author: MrAl
author_rank: Super Contributor
timestamp: April 10, 2025, 12:37:05 pm
content: Quote from: TimFox on April 09, 2025, 03:09:35 pmThat horse has been dead for a long time now.I really don't care what has to be done, as long as it's done. Far higher voltage, far lower voltage, whatever has to be done to improve the grid. Higher voltage is usually the way to go, but I also noticed other things that help. For one example, the local environment. Trees are a big issue in some areas because the wires run through or past them. There is ongoing work to fix that issue in some parts of this state.BTW, this thread is not really about pro's and con's of improving the grid it was originally something else, so maybe start a new thread if you want to continue this discussion cause I'm about done talking about the same thing over and over again. We went over all this stuff already.

author: MrAl
author_rank: Super Contributor
timestamp: April 11, 2025, 01:38:34 pm
content: Quote from: incf on March 29, 2025, 05:55:45 pmHello again,Ok back on TopicI had another thought, and that was if we installed thermal fuses in every outlet, then if one does trip who is going to fix it?There could be some laws that prevent fixing them without calling an electrician, and that could be a pain in the neck. Maybe safer overall though.Just some quick thoughts on it.

author: tooki
author_rank: Super Contributor
timestamp: April 11, 2025, 01:44:36 pm
content: Fuse holder on the front? Or just make it a circuit breaker, with a reset button just like GFCI outlets.

author: incf
author_rank: Frequent Contributor
timestamp: April 11, 2025, 02:03:53 pm
content: Quote from: MrAl on April 11, 2025, 01:38:34 pmYou or an electrician replaces the entire $2 outlet module with a new one since its contacts are probably worn out, or it was installed with a loose connection to mains. It's better than having the outlet melt in an uncontrolled fashion.

author: MrAl
author_rank: Super Contributor
timestamp: April 12, 2025, 04:41:59 pm
content: Quote from: incf on April 11, 2025, 02:03:53 pmYes, I guess so, but I was talking more about places that do not let you do any electrical work yourself. You have to have a licensed electrician come in and pay them (ha ha). You could get fined if you do the work yourself and they find outKeep in mind that an electrician can get $100 just to come to the house before doing any work.But I think you are on to something. Maybe the thermistors PLUS a little beeper that alerts the user that the outlet temperature is getting too high, and if not addressed by a certain temperature, then the outlet shuts down like the ground fault interrupters. Then MAYBE, have a button to reset it but only after the temperature comes back down.That would stop this problem from happening and not require replacing the outlet.There is still the question of where to place the thermistors though. That could be tricky.

author: Teledog
author_rank: Regular Contributor
timestamp: April 13, 2025, 03:00:44 am
content: Hay kids! Just get the "Snug Plug"https://www.amazon.com/Snug-Plug-Your-Loose-Outlet/dp/B0DL7V5RB1?th=1All problems resolved!..Not..

author: golden_labels
author_rank: Super Contributor
timestamp: April 13, 2025, 03:16:27 am
content: In case you wish to use that idea commercially, be aware that a shim making the plug fit better is patented: US9859656B2.

author: tooki
author_rank: Super Contributor
timestamp: April 13, 2025, 11:43:48 am
content: Quote from: golden_labels on April 13, 2025, 03:16:27 amUh, yeah, duh: that’s the commercial product linked in the reply just above yours.Not that those shims are a good idea in any way.

author: Xena E
author_rank: Frequent Contributor
timestamp: April 13, 2025, 12:54:24 pm
content: Heres my invention:Thermal fuse, (perhaps 'woods metal' or similar), that if heated by a bad contact in the socket, release a sprung plunger pushing out the plug, and defeat any attempts to reinsert it.It has already been done, before any haters jump on this post.The biggest problem with that is that you're not going to get them for a couple of bucks, so Joe average isn't going to be buying them.X

author: incf
author_rank: Frequent Contributor
timestamp: April 13, 2025, 01:34:54 pm
content: Soldering in a handful of non-replaceable single use glass thermal fuses would be sufficient.Unfortunately, costing 8 cents (US) per fusible element, and requiring 8 fuses it would increase the material cost of a 97 cent outlet module by more than 50%.While I personally would be willing to pay $2 (about 100% more) for a single use thermally fused outlet, it might be difficult to sell anyone except an insurance company on the idea.

author: golden_labels
author_rank: Super Contributor
timestamp: April 13, 2025, 01:51:10 pm
content: Quote from: tooki on April 13, 2025, 11:43:48 amUh, yeah, duh: that was my reply to the post just above mine.

author: themadhippy
author_rank: Super Contributor
timestamp: April 13, 2025, 02:19:19 pm
content: Quotegood luck with that

author: incf
author_rank: Frequent Contributor
timestamp: April 13, 2025, 02:46:20 pm
content: Quote from: themadhippy on April 13, 2025, 02:19:19 pmWould soldered joints cause the factory issues?

author: Xena E
author_rank: Frequent Contributor
timestamp: April 13, 2025, 03:00:15 pm
content: Quote from: incf on April 13, 2025, 01:34:54 pmLow temperature ones are, for instance, best crimp connected don't you think?

author: incf
author_rank: Frequent Contributor
timestamp: April 13, 2025, 03:09:29 pm
content: Quote from: Xena E on April 13, 2025, 03:00:15 pmSure crimp would be better than solder. Is it common to crimp solid metal leads/wires? I imagine it must take a *lot* of force to form a gas tight seal around a sold chunk of metal.

author: Xena E
author_rank: Frequent Contributor
timestamp: April 13, 2025, 03:21:39 pm
content: Ones I've seen are, generally as common connections to things like consumer goods, heaters hairdryers etc.,I'd think for a power socket you would need it to cut out at a sustained temperature well within the abilities of the construction.I think the highest permissible operating temperature of UK BS1363 is 70°C... so if it opened at 100°C a soldered in component could be a problem at manufacture.I don't like crimp on solid myself but it can be done.X

author: tooki
author_rank: Super Contributor
timestamp: April 13, 2025, 05:19:28 pm
content: Quote from: golden_labels on April 13, 2025, 01:51:10 pmYour wording (in particular, using the indefinite article in “a shim”) suggested you werenotreferring to the just-mentioned item.

author: tooki
author_rank: Super Contributor
timestamp: April 13, 2025, 05:25:07 pm
content: Quote from: incf on April 13, 2025, 03:09:29 pmNo more force than doing it with stranded wire of the same cross-section, assuming the same material.Crimping solid wires is not common (because it is even more fickle than crimping to stranded wire) and has absolutely no tolerance for nicked wire or overcrimping. But it is done sometimes, especially for wires that cannot be soldered (e.g. because of high operating temperature, like the hair dryers Xena E mentioned).But for this, you’d just form the fuse holder into the other sheet metal for the contacts, just like e.g. British plugs do, but then just seal the receptacle enclosure with rivets or similar. You could also spot-weld instead.

author: incf
author_rank: Frequent Contributor
timestamp: May 01, 2025, 08:57:05 pm
content: and the photos continue to roll inedit: remember, the person who took that photo is not in this thread.edit 2: This particular photo initially looked "less backstabby" and was melted, so I figured I would add it to the existing pile of photos of melted outlets in hopes that someday I might find a more direct/definitive answer to my original set of questions.

author: Stray Electron
author_rank: Super Contributor
timestamp: May 01, 2025, 10:59:30 pm
content: That looks like another failure of a stab connection. You can see that most of the burning was behind the terminal with the brown wire.

author: Monkeh
author_rank: Super Contributor
timestamp: May 01, 2025, 11:20:56 pm
content: Quote from: Stray Electron on May 01, 2025, 10:59:30 pmThere's no wires in any of the stab connections or failure of the housing at those points..

author: Xena E
author_rank: Frequent Contributor
timestamp: May 01, 2025, 11:23:19 pm
content: Looks like a loose fitting plug may have caused that to me

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 02, 2025, 12:49:48 pm
content: I'm wondering what would have been the final result if the outlet was in a plastic junction box, instead of being contained in a metal box....hmmmmm

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 02, 2025, 01:20:10 pm
content: If US standard color coding was used, the hot and neutral are swapped on your most recent “example”. There are other very questionable things going on within that box that I will not bother to explain other than to say it’s a complete DIY hack disaster.Work being done by unqualified idiots that have no business mucking about with mains wiring is the main cause of most of the problems you’ve discussed in this thread.Fuses and other unnecessary ideas aside, you simply cannot fix stupid.I can buy surgical tools to cut bone but that doesn’t make me a brain surgeon.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2025, 01:22:58 pm
content: Quote from: incf on May 01, 2025, 08:57:05 pmWhat's going on with the thin brown wire between the two wirenuts?Edit: I guess that comes under the 'unqualified idiots' category.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 02, 2025, 01:25:04 pm
content: Quote from: Gyro on May 02, 2025, 01:22:58 pmIt’s a bare copper earth wire. Hopefully connected to the metal box, somewhere, somehow. It does not appear to be, which is a code violation.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2025, 01:26:04 pm
content: Ah ok. Yes hopefully in that case. Yuk!It looks like the carbonized wire, just visible in the plastic conduit, probably went the the very burnt screw before it melted (it's missing some length otherwise).

author: incf
author_rank: Frequent Contributor
timestamp: May 02, 2025, 01:29:13 pm
content: I spent more time than I care to admit looking at the photo (messing around with brightness/contrast curves, etc.)I believe the outlet was wired correctly.There are a few potential optical illusions in the photo that make the paths of the wires difficult to follow at first.Thermal fuses would have prevented it from melting.Quote from: BILLPOD on May 02, 2025, 12:49:48 pmIf it was in a plastic box, it would have been even worse. The "self-extinguishing" property of certain plastics only applies after the heat source has been removed - which would never happen in a regular circuit if it was unattended.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 02, 2025, 01:31:13 pm
content: I seriously question why the hot and neutral arrive in separate conduits. One conduit connector (or pipe?) is not bonded, another code violation.This thread should be titled “examples of how DIY raises insurance costs”Trying to solve problems created by idiots is a fool’s errand. The idiots beat you with experience every time.

author: themadhippy
author_rank: Super Contributor
timestamp: May 02, 2025, 01:37:14 pm
content: maybe the earths come loose causing it to overheat through overcurrent

author: Xena E
author_rank: Frequent Contributor
timestamp: May 02, 2025, 04:25:36 pm
content: Quote from: WattsThat on May 02, 2025, 01:31:13 pmThats a big no no! That will induce eddy current in the conduit just as if it were a shorted turn C/T.Quote from: themadhippy on May 02, 2025, 01:37:14 pmIf you refer to the Eddy current, I think it will just circulate in the conduit perhaps not causing any end to end potential.Still, it will warm those tubes up a bit with paid for electricity.X

author: Langdon
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:37:36 pm
content: Quote from: incf on May 01, 2025, 08:57:05 pmNote these code violations in the photo:1. Some wires are shorter than 3 inches, measured from where they enter the box. The National Electrical Code states that all wires must be at least 3 inches.2. One conduit has no ground wires at all, the other has 2; there's a green wire, and a very badly corroded and extremely short bare copper wire.3. The "conduit" is actually steel pipe; this isn't inherently bad, but you should use electrical conduit for electrical stuff 'cause that's what it's for!4. Box is old, corroded, and weathered; who reuses a corroded box when you can buy a new one for like $6 or less?

author: Langdon
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:41:49 pm
content: I recommend you just scrap everything (except perhaps for wires that aren't corroded) and start from scratch.There's so many code violations and it's all so strangely put together, who knows what caused the problem!!!It could be a ground fault, corrosion causing poor conduction and making heat, worn out wires affected by metal fatigue and corrosion, or a dozen other things.

author: Langdon
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:51:25 pm
content: I think corrosion is the main culprit here.Copper oxides and the green patina don't conduct electricity well, and are brittle and weak.Corroded electrical boxes don't carry current though their ground screws like they should very well.That's why ground wires should be pigtailed, with one wire connecting to the box.Grounding through the box is generally fine, but might cause major problems.Copper wire is better than aluminum (if you had aluminum wiring, you would probably be dead by now, considering how the copper is faring).Buy new outlets, or find old ones that are not corroded or worn, and install them.Consider purchasing AFCI (Arc Fault Circuit Interruptor) breakers.

author: incf
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:56:00 pm
content: Quote from: Langdon on May 02, 2025, 08:41:49 pmQuote from: Langdon on May 02, 2025, 08:51:25 pmRemember, the person who took that photo is not in this thread.The photos are random ones taken from various electricians' forums and groups.The photos only exist to explain why this thread exists (asking about thermally protected outlets). If I didn't have the context that those sort of photos provide this thread couldn't really exist in any meaningful capacity.Hopefully I can avoid causing too much confusion.This particular photo initially looked "less backstabby" and was melted, so I figured I would add it to the existing pile of photos of melted outlets in hopes that someday I might find a more direct/definitive answer to my original set of questions.

author: Langdon
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:58:56 pm
content: In Canada (my country), AFAIK, outlets, outlet covers are never made of normal plastic.The white outlets (and covers) are ceramic.The brown outlets (and covers) are some sort of high-temp and high-dielectric-strength phenolic meterial.Maybe USA has lax regulations on outlet materials.Perhaps buying Canadian-made outlets is the solution!

author: themadhippy
author_rank: Super Contributor
timestamp: May 02, 2025, 09:42:23 pm
content: QuoteDont the regs allow for metal conduit to be used as the earthing conductor?Here in the uk its perfectly acceptable.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 03, 2025, 01:00:45 am
content: Quote from: themadhippy on May 02, 2025, 09:42:23 pmYes, US NEC does allow for grounding through metallic tubing but a separate, dedicated green or yellow/green wire for grounding is preferred. In the use case of NM type residential wiring, the ground wire is bare copper.We don’t use much metal tubing in residential work, mostly pvc were exposed or in concrete.

author: TimFox
author_rank: Super Contributor
timestamp: May 03, 2025, 04:33:09 am
content: The legal electrical code depends on the jurisdiction.In Chicago, metal conduit is required for both domestic and commercial buildings.The protective earth connectionis in my house are done through the conduit, but there is a heavy grounding system at the breaker box and meter (large green wire inside dedicated conduit).

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 03, 2025, 02:28:51 pm
content: Not wanting to be pedantic but legal would not be the term I would use, applicable is a better description of the situation in the US.Every state, city, county and township, depending upon where you are in the US - will have its own set of unique codes that it feels is appropriate that you’ll have to met to receive a permit and or a successful inspection to be allowed to place the building or whatever the thing may be into service.Usually it will be tied to a specific year of the National Electrical Code (NEC) and/or the National Fire Protection Association (NFPA) along with some local changes and details thrown in because they can. For example, my home’s county requires a dedicated 20 amp branch circuit for a dishwasher that must be hardwired, no plugs and receptacles allowed. No doubt due to a rash of fires at some point. As they say in aviation, all the rules are written in blood.Another example: Chicago and LA are some of the larger cities that for industrial installations, all control panels must have a UL (Underwriter Labs, a third party) inspection label before they will allow power to be connected to that panel.The plumbing codes are even more convoluted. A plumber licensed in Pennsylvania and doing work in Washington state would find his work failing inspection for a number of reasons.Welcome to ‘Merica

author: TimFox
author_rank: Super Contributor
timestamp: May 03, 2025, 02:34:56 pm
content: “Legal” is a normal term for what is required by local ordinances and has force of law.Yes, the applicable electrical code varies with location in the US, usually based on the NEC (which is not, in itself, a statute).

author: Langdon
author_rank: Frequent Contributor
timestamp: May 07, 2025, 03:24:04 pm
content: That's not conduit tho.That's pipe.Conduit is an acceptable grounding conductor, so long as it has ground continuity.I don't think pipe is technically permitted as a grounding conductor by applicable codes.(though it should work)