house outlet ac power - Page 1
Forum section: electronics / beginners

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 09, 2022, 01:42:24 pm
content: I hear that America is 120v, and Australia is 240v.But is that the distance between the most positive point of the wave and most negative point. so its actually 60 high and 60 low, for a total of 120, or is it 240 + to - for 120 volt america.So is it the same for australia - excepts its double?

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 09, 2022, 01:59:29 pm
content: I guess you need to learn a little bit about basic electricity. The 120V or 240V isn't about distances.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 09, 2022, 02:03:02 pm
content: there is a positive cycle and negative cycle is there not?So im asking whats the peak negative and peak positive volts, of the live wire.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 09, 2022, 02:07:27 pm
content: The peak for the 120VAC in the USA is +170 to -170. For the 240V it's +339 to -339.

author: Gyro
author_rank: Super Contributor
timestamp: January 09, 2022, 02:09:29 pm
content: The 120V and 240V are RMS voltages, not Peak to Peak.https://www.electronics-tutorials.ws/accircuits/rms-voltage.html

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 09, 2022, 02:19:33 pm
content: thankyou. RMS. yes I didnt know this.So 120 RMS has to do with summing it up over time?If its a square wave wouldnt you get 120 volts dc with less peak?

author: mcz
author_rank: Contributor
timestamp: January 09, 2022, 07:19:49 pm
content: Quote from: Capernicus on January 09, 2022, 02:19:33 pmFor a square wave you have the luxury of the amplitude beeing equal to the RMS voltage. So 120Vp (single peak, not peak to peak!) get you 120Vrms.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 09, 2022, 09:06:27 pm
content: Yeh I see now. because the negative half is a different phase than the positive half, they dont add up to double.

author: bdunham7
author_rank: Super Contributor
timestamp: January 09, 2022, 09:15:16 pm
content: Quote from: Capernicus on January 09, 2022, 09:06:27 pmExcept in the US, where it does.https://en.wikipedia.org/wiki/Split-phase_electric_power

author: David Hess
author_rank: Super Contributor
timestamp: January 10, 2022, 07:21:23 pm
content: The US uses split phase, so 120VAC is 120 volts RMS, 170 volts peak or 340 volts peak-to-peak, centered around neutral/ground, and 240VAC is 240 volts RMS, but made from two 120VAC outputs which are 180 degrees out of phase.At the transformer, the secondary is 240VAC with a center tap attached to neutral, and neutral is attached to Earth ground at the distribution panel. Inside the building, the 120VAC sockets are distributed between the two 180 degree phases, which means in theory 240VAC can be regained by using the hot lead from two different sockets, not that I would ever have done that. Also, I have never wired a duplex output with one phase on one outlet and the other phase on the other outlet. That is my story and I am sticking to it.

author: Shock
author_rank: Super Contributor
timestamp: January 10, 2022, 08:53:34 pm
content: Quote from: Capernicus on January 09, 2022, 09:06:27 pmSame phase just second half of the cycle. The potential for current is induced by rotating a magnet past a coil. So it goes to becoming very positive in the first half of the rotation cycle to very negative in the second half.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 10, 2022, 09:28:03 pm
content: OK.In the US and the voltage available in the home is 220 or 110. This is because two phase domestic power is the norm there.https://upload.wikimedia.org/wikipedia/commons/c/cc/World_Map_of_Mains_Voltages_and_Frequencies%2C_Simplified.pngYour basic outlet is 110V and you get bigger 220V outlets for stoves and such.Why mix it up, I dont know. Its was not safer back in the day. GFCIs (RCDs) makes this less relavent now of course.In most countries you typically get 230-250 so you dont need mad amounts of copper and you only need a single plug type.

author: bdunham7
author_rank: Super Contributor
timestamp: January 10, 2022, 09:40:10 pm
content: Quote from: Terry Bites on January 10, 2022, 09:28:03 pmProbably for compatibility with early systems that were actually 110V only in single-unit houses. What do you mean about safety and plugs? You still have half the voltage phase-to-ground that you have in EU/Aus/etc. And most 240V devices don't plug in at all and those that do (dryers, say) use a much larger plug than would be practical for ordinary appliances, so you would still have to have different plugs.

author: TimFox
author_rank: Super Contributor
timestamp: January 10, 2022, 10:18:55 pm
content: The US NEMA connectors used for 120 V, 240 V, and three-phase wall sockets and cable plugs are well-defined and required for conformance to NEC electrical codes.

author: IanB
author_rank: Super Contributor
timestamp: January 10, 2022, 10:53:23 pm
content: Quote from: Terry Bites on January 10, 2022, 09:28:03 pmFortunately for me, my home has 240 V and 120 V. This enables me to use a 240 V electric kettle imported from the UK at full power.QuoteAccording to this excellent YouTube presenter, the reason goes back to the pioneering days of electricity, when Edison invented the carbon filament electric lightbulb. It was very difficult to make carbon filament lamps work from higher voltages than about 120 V or so, which caused the supply voltage to be set at this level.Later on, the tungsten filament lamp was introduced, which could easily be made to operate at 240 V, but by that time there were so many carbon filament lamps in use in America that it was very difficult to change the standard, so it stuck, even when DC moved over to AC.In the rest of the world, it was recognized that higher voltages permitted lower currents and thus less copper in the wiring, and carbon filament lamps were less prevalent, so they settled on 220 to 240 V and everyone went straight to tungsten lamps.

author: tooki
author_rank: Super Contributor
timestamp: January 10, 2022, 11:04:52 pm
content: Quote from: Terry Bites on January 10, 2022, 09:28:03 pmMains voltage in USA hasn’t been 110/220V for the better part of a century. It’s 120/240V.

author: fordem
author_rank: Regular Contributor
timestamp: January 11, 2022, 02:09:34 am
content: Quote from: Terry Bites on January 10, 2022, 09:28:03 pmUSresidentialpower is not two phase, it's single phase, split phase - think center tapped transformer and you'll get the big picture.

author: Brumby
author_rank: Unknown
timestamp: January 11, 2022, 07:57:48 am
content: Here's a question I've been meaning to ask for a while....What difference is there between two phase and split phase?(I have an answer, but I'd like to see what others think.)

author: Gyro
author_rank: Super Contributor
timestamp: January 11, 2022, 09:37:20 am
content: I'd have though that two phase would be something like what is fed to the windings of an induction motor - one phase being directly driven and the other phase being shifted by the run capacitor.I can't really think of many things that aren't either three (or more) phases, or single phase.P.S. I think the clearest definition of US mains is 240V Centre tapped - that's how we normally refer to transformer secondaries (which is what it is).

author: Shock
author_rank: Super Contributor
timestamp: January 11, 2022, 10:21:45 am
content: Single, two and three phase systems are 120 degrees out of phase. Split phase is 180 degrees, they seem to use a center tapped transformer.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 11, 2022, 11:17:31 am
content: Why isnt all ac power a square wave, makes it all simpler.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 11, 2022, 12:26:20 pm
content: It's not easy to build a generator that delivers square wave. Yeah with inverter from DC power it's easy but not so with an engine or other mechanical source turning an alternator.

author: Brumby
author_rank: Unknown
timestamp: January 11, 2022, 12:33:21 pm
content: Quote from: Shock on January 11, 2022, 10:21:45 amHow can a single phase be out of phase?QuoteWhy 120º ? Could be any angle in the range of 0º < Φ < 360º, couldn't it?QuoteThat's the sensible approach.QuoteI believe they do.

author: Brumby
author_rank: Unknown
timestamp: January 11, 2022, 12:38:10 pm
content: Quote from: Capernicus on January 11, 2022, 11:17:31 amDefine "all"..... because all I'm coming up with is a bucketload of problems!!

author: Caliaxy
author_rank: Frequent Contributor
timestamp: January 11, 2022, 01:05:40 pm
content: Quote from: BeBuLamar on January 11, 2022, 12:26:20 pmAnd imagine all those harmonics…

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2022, 02:41:06 pm
content: Quote from: Capernicus on January 11, 2022, 11:17:31 amBecause a generator rotates in a circular fashion, and the sine and cosine functions are called the circular functions. It naturally follows that a generator produces a sine wave output.If you could work out how to make a square wheel, and how to make the interior of a generator to be square shaped instead of round, then you could make a generator produce a square wave output.

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2022, 02:48:32 pm
content: Quote from: Brumby on January 11, 2022, 07:57:48 amMathematically, split phase has two phases. If you want N balanced phases, you divide the circle of 360° or 2π into N equal divisions, and that is the angle between phases.So two phases are 180° apart, three phases are 120° apart, four phases are 90° apart, and so on.But to electrical engineers, having two phases 180° apart lacks utility, so they reserve the term "two phase" for cases where the two phases are not balanced.So split phase has two equally distributed phases, but it is not "two phase"

author: CaptDon
author_rank: Super Contributor
timestamp: January 11, 2022, 03:13:06 pm
content: IanB, that is an excellent description of 'split phase' vs. 'two phase' and in fact in one of my Tektronix TM (Transport Module 500 series TM506 specifically) operators manual it indicates "If running from 240vac the unit is NOT designed to operate on two phases of a 3 phase circuit, (typically a 208 Y connection) but intended to be operated from single/split phase". We had a transformer (around 3kva if I remember correctly) in a lab and it always ran hot and sounded 'angry' with a weird raspy buzz. Turns out it was a 120/120 dual primary and they wired it for 240 which was o.k. in itself, but they hooked ALL THREE wires, the far ends and the center tap to 208Y !!!! Center tap was connected to Neutral!!! After pulling the center tap off the neutral connection the transformer was much happier!!I am sure that transport module would get really pissed off with a 3 wire connection to 208Y since it also has a big transformer inside!!!

author: Shock
author_rank: Super Contributor
timestamp: January 11, 2022, 03:50:54 pm
content: Quote from: Brumby on January 11, 2022, 12:33:21 pmDepends where you live but you can have two neighbors with out of phase single phase systems. Typically single and three phase systems in the street are derived from the same wiring. Or you might get a whole street on the same phase supplied via a transformer. Next street over, different phase. Two phase systems I suspect are legacy, probably just saves running a wire for a small premises that needs two out of three phases.

author: tooki
author_rank: Super Contributor
timestamp: January 11, 2022, 03:58:53 pm
content: Quote from: Capernicus on January 11, 2022, 11:17:31 amStart with the fact that a square wave is a sum of infinite sine waves: a sine wave at the fundamental frequency, plus sine waves at all the odd harmonics (e.g. if your square wave is 100Hz, then it’s composed of the sum of sine waves at 100Hz, 300Hz, 500Hz, etc. theoretically to infinity).

author: fordem
author_rank: Regular Contributor
timestamp: January 12, 2022, 01:28:23 am
content: Quote from: IanB on January 11, 2022, 02:48:32 pmI would change one line in this "definition" - half a line actually - they reserve the term "two phase" for cases where the phase angle is not 180°Single phase will have a single hot line & a neutral, split phase will have two hot lines & a neutral, the phase angle between the two hot lines will be 180°, two phase will have two hot lines & a neutral, with a phase angle between the hot lines of anything other than 180° (usually 120° or 240°), three phase will have three lines (there may or may not be a neutral) and the phase angle between the hotlines will be 120°

author: bdunham7
author_rank: Super Contributor
timestamp: January 12, 2022, 03:21:34 am
content: Quote from: fordem on January 12, 2022, 01:28:23 amThat would be two phases of a three-phase system, typically seen in apartment buildings with 208/120 Wye 3-PH where the provide two legs for stoves, water heaters and electric dryers.Two-phase, AKA the original polyphase, AFAIK just had 4 wires and no neutral, with the voltage on one pair of wires 90 degrees out of phase with the other.

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2022, 03:41:40 am
content: Quote from: bdunham7 on January 12, 2022, 03:21:34 amI wouldn't like that system. 208 V has only 3/4 the power of 240 V

author: bdunham7
author_rank: Super Contributor
timestamp: January 12, 2022, 03:47:33 am
content: Quote from: IanB on January 12, 2022, 03:41:40 amThey make 208V elements for water heaters, dryers can work fine with a little less heat, stoves and ovens you just have to deal with it. Electric motors up to 5HP are often rated for 208-240VAC single phase, but I can tell you that they aren't as happy at 208V. I had a large commercial building that only had one large 208/120 service entrance.

author: David Hess
author_rank: Super Contributor
timestamp: January 12, 2022, 04:11:42 am
content: The last time I changed some water heater elements, they were intended for 208 and 240 VAC operation and marked with different power levels.

author: mcz
author_rank: Contributor
timestamp: January 12, 2022, 09:50:19 am
content: Quote from: tooki on January 11, 2022, 03:58:53 pmTo give a bit more insight into why this is a bad thing:1. Generators used to supply sinusoidal waveforms, mostly 3 phase AC since a hundred or so years.2. The inductance and capacitance of the power transmission lines would filter out the higher frequencies of that square wave, rounding it off a bit.2.1 same goes for transformers on the power grid.2.2 this also needs a lot more reactive power which means more current on the transmission lines -> bigger lines -> more money3. The transformer (those things get used a lot in power delivery) does not like high frequency. The higher the frequency, the more losses you get for a given iron core material. Cores are already designed to deal with these losses and reduce them to a point where a transformer has 99% efficiency at nominal power. But introducing higher frequency will up these losses and waste money and heat the transformer.. which would need bigger cooling.4. Same goes for all the 3-phase (and also 1-ph) motors that get used everywhere in industry and run the western world when it comes to moving things.5. 3 phase power with square waves would be all weird and wonky.And it does not really have any significant, real world benefit. You get the downsides of DC with the downsides of AC combined and none of the upsides I guess.

author: Brumby
author_rank: Unknown
timestamp: January 12, 2022, 10:01:21 am
content: Quote from: IanB on January 11, 2022, 02:48:32 pmAh - so a "convention" is in place. I've not heard of that being stated explicitly, but it is not unreasonable and it does fit in with previous usage I have encountered.

author: Brumby
author_rank: Unknown
timestamp: January 12, 2022, 10:17:16 am
content: Quote from: Shock on January 11, 2022, 03:50:54 pmA bit outside the box I was thinking about - but that is a fair point.QuoteThis has consistently been my observation. A pole transformer with a 3 phase Y secondary providing 4 wires down the street. With 3 hot wires and a neutral, every house has a connection to the neutral plus a connection to 1, 2 or 3 of the hot wires.QuoteCan't say I've seen whole streets on the one phase. Whenever I've looked, they tend to alternate houses so that the number of houses connected to each phase is roughly the same. Pick any 6 houses together and you'll likely see 2 on each phase. (It seems these days, single phase house supply is more the norm. Where I grew up, 3 phase to houses was common.)Two phase houses are around, but not too common.

author: TimFox
author_rank: Super Contributor
timestamp: January 12, 2022, 02:43:35 pm
content: Power distribution systems vary locally.In my residential block in Chicago, a pole transformer (probably fed with 4000 V, single-phase) has a secondary at approximately 240 V, center-tapped, that feeds about 14 houses that share the alley.At my former employer, a light manufacturing location, the original building was fed with 208 V (three-phase, line-to-line, with neutral) that provided three-phase and 120 V single-phase to the outlets and HVAC.When the building was expanded, a second feed included 208 V and approximately 480 V three-phase from a second transformer.At my employer, when we needed to consider options for powering equipment in the US, I found useful information at our local utility's website:https://www.comed.com/SiteCollectionDocuments/MyAccount/MyService/ServiceAppCommercialIndustrial.pdfThe end of this form has check boxes for the readily-available options on page 3.

author: bdunham7
author_rank: Super Contributor
timestamp: January 12, 2022, 03:31:42 pm
content: Quote from: TimFox on January 12, 2022, 02:43:35 pmYikes! They still offer 120/240 3PH 4W, which has inherent power quality problems due to the built-in phase imbalance. Last I knew at least some utilities would not provide that for new installations and for any decent size commercial building it is pretty standard by now to have 277/480 3PH for the large loads--including lighting--and then 120/240 1PH for the outlets, office equipment, etc.

author: TimFox
author_rank: Super Contributor
timestamp: January 12, 2022, 04:25:53 pm
content: The other options on that line are far more common (240 VCT, 208 V + neutral 3-phase, 480 V + neutral 3-phase).One of my co-workers doing some work on his old church building in Joliet was surprised to encounter the 240 V 3-phase with the center of one pair of lines grounded: it makes a difference!Note that one of the options on the second line (480 V, B-phase grounded) is not allowed in the City of Chicago: this utility company covers much of Illinois.

author: themadhippy
author_rank: Super Contributor
timestamp: January 12, 2022, 04:33:07 pm
content: you yanks really like to over complicate things,how many options? Here in the uk you get 230V ( its really 240 but in the name of harmony we pretend) single phase,or 415V 3 phase.If you really ask nicely they might let you have 11kv.

author: TimFox
author_rank: Super Contributor
timestamp: January 12, 2022, 05:35:23 pm
content: The three options I referred to are common here. I assume the complete list results from the stock transformers available to the utility from manufacturers, to include replacement for older industrial equipment that is long-lived. Variety is the spice of life, or so they say.

author: bdunham7
author_rank: Super Contributor
timestamp: January 12, 2022, 06:00:13 pm
content: Quote from: themadhippy on January 12, 2022, 04:33:07 pmIt isn't as difficult as it appears, the actual distribution is typically HV--4kV range on older systems, 12kV range on newer--right up to the customer and then there is a transformer at the point of use. So the customer's actual service configuration is often just a matter of installing the specific transformer(s) and meter(s) required. I have a single phase of 12kV right in my backyard.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 12, 2022, 07:06:50 pm
content: Good Morning, not to complicate things, but when the primary distribution is 7.2 KV 'Delta', then a 3-phase service has a'WILD LEG' whose voltage could be anything.

author: Zero999
author_rank: Super Contributor
timestamp: January 12, 2022, 10:14:52 pm
content: I was told that two phase has always been 90° out of phase. I've also heard the term being used to describe split phase and two phases, off a three phase supply, which only makes and difference, if there's a neutral.

author: TimFox
author_rank: Super Contributor
timestamp: January 12, 2022, 10:57:48 pm
content: In a different application, that is the difference between a “selsyn” (3 phase) and a “resolver” (2 phase), which are AC-excited analog rotation sensors used in servos. The three phases in the selsyn are 120 deg apart, and the two phases of the resolver are 90 deg apart.

author: Shock
author_rank: Super Contributor
timestamp: January 12, 2022, 11:19:44 pm
content: Two phases are any two phases, split phase is one phase split in two.These days if you are getting provisioned and have 3 phase on the street you will get 3 phase if you ask for it. As bdunham7 mentioned they may give you two phases in an apartment.You can use phase to phase or phase to neutral. On split phase there is no phase to phase. In apartments you are likely limited to the body corporate and code. So don't be messing with your mains supply if you just discovered you have two or three phases.Someone mentioned 208V that sounds like phase to phase 120V. Here phase to phase is 415V.

author: Brumby
author_rank: Unknown
timestamp: January 13, 2022, 12:29:19 am
content: Quote from: Shock on January 12, 2022, 11:19:44 pmI've just upgraded my service. New meter box, new smart meters, new breakers .... and 3 phase (was previously single phase).Reason: New plans requiring upgrade. Major air conditioning upgrade and solar power projects in the wind - with possible upgrade to garage power and being able to deal with an EV (if that ever eventuates).

author: IanB
author_rank: Super Contributor
timestamp: January 13, 2022, 03:16:33 am
content: Quote from: Shock on January 12, 2022, 11:19:44 pmBut in fact, split phase gives you two phases 180° apart, which is half of 360° (three phase gives you three phases 120° apart, or one third of 360°).QuoteIn North America, phase to phase is standard on a split phase supply and gives 240 V for higher power applications like cooking, heating and A/C.QuoteActually, in North America there is a "poor man's 240 V". If you take the line voltage from two different outlets in your house which are on different phases you can derive a 240 V supply. There are even special extension cords to make this more convenient. They have a 240 V socket on a wye with two 120 V plugs that you insert into different outlets. It's a bit hokey, but it saves having to wire a dedicated 240 V circuit from the main panel when you only have an occasional need.

author: bdunham7
author_rank: Super Contributor
timestamp: January 13, 2022, 03:24:33 am
content: Quote from: IanB on January 13, 2022, 03:16:33 amThat sounds sparkly. Especially if you happen to have a miswired socket and a Sylvania/Zinsco panel.

author: IanB
author_rank: Super Contributor
timestamp: January 13, 2022, 03:32:33 am
content: If someone has swapped line and neutral on some sockets in your house, you have problems.When I moved in I went round and tested every outlet with a socket tester. I do have one outlet where the ground connection is open circuit, but since I know about that limitation I can live with it. The fault is unfortunately deep inside the attic and I don't have the energy to trace the wiring.

author: Shock
author_rank: Super Contributor
timestamp: January 13, 2022, 01:27:10 pm
content: Some loose wire nut no doubt heheh.

author: Zero999
author_rank: Super Contributor
timestamp: January 13, 2022, 01:36:06 pm
content: In the UK, we have 400V three phase, 230V to neutral, but most domestic consumers only have single phase available. Some European countries have 230V three phase, 133V to neutral, but only 230V is used as far as I'm aware, so 230V single phase appliances are connected across two phases.

author: mcz
author_rank: Contributor
timestamp: January 13, 2022, 02:25:24 pm
content: Quote from: Zero999 on January 13, 2022, 01:36:06 pmI wonder why that is. The typical length of wire from the street into the house is really not that long compared to the wiring that supplies the neighborhood. Might as well bring in all 3 phases?And yes I do live in a country where they do exactly that. Yeah, typical fusebox/whatever you call that might be more expensive. But that's not something the power company has to pay..

author: TimFox
author_rank: Super Contributor
timestamp: January 13, 2022, 02:30:43 pm
content: Quote from: Shock on January 12, 2022, 11:19:44 pm208 V: this is a standard three-phase line-to-line voltage in the US, which gives the normal 120 V line-to-neutral for US standard appliances.

author: IanB
author_rank: Super Contributor
timestamp: January 13, 2022, 03:18:19 pm
content: Quote from: mcz on January 13, 2022, 02:25:24 pmTypical service in the UK is 100 A, which allows even 12 kW loads like water heaters that draw 50 A. So there isn't really a need for more than one phase. And of course it really simplifies the house wiring to have only one phase coming in.

author: TimFox
author_rank: Super Contributor
timestamp: January 13, 2022, 03:59:58 pm
content: Typical service for a single-family house in Chicago is 200 A at 240 V center-tapped. I get by with a 100 A breaker panel.My largest electrical load is the air conditioner (240 V)--cooking, heat, and water heater use natural gas.

author: themadhippy
author_rank: Super Contributor
timestamp: January 13, 2022, 04:21:38 pm
content: QuoteMaybe on newer stuff,but older installs 60 or 80A is more common,even seen it as low as 40A.And even if the fuse carrier says 100A,that's only it maximum rating and isn't always whats fitted.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 13, 2022, 04:32:25 pm
content: question:: what happens exactly if you just your run off a 60hz 240volt spark gap oscillator, does it still work?So I mean with the negative polarity. I spose it depends on how you do it, has anyone done it before?

author: Terry Bites
author_rank: Super Contributor
timestamp: January 13, 2022, 05:22:15 pm
content: I heard that is, like so many things, the fault of Edison. Who mated with A Coffin egged on by JP Morgan of total corruption fame producing the demon seed for satan's own GE.(GE engineers are good guys, they just work for ******g b**st***s. Allegedly)Tommy Edison had a thing about Long legged Mary Ann. She was luke warm and only gave 110V and Edison bought five of them for his first power station.So he stuck with them. He loved dynamo hum. Did he marry Mary Ann? Maybe it was just a fling when AC-DC was still taboo.I heard this on Utoob so it may be complete cow sh**e.

author: Zero999
author_rank: Super Contributor
timestamp: January 14, 2022, 10:56:39 am
content: Quote from: Capernicus on January 13, 2022, 04:32:25 pmWhat do you mean by that word salad?Quote from: themadhippy on January 13, 2022, 04:21:38 pm40A is ample for most UK homes. Air conditioning is uncommon and the heating is mostly natural gas. This might change in future with more homes having heat pumps and car chargers, in which case upgrades will be necessary.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 14, 2022, 11:40:51 am
content: Quote from: Zero999 on January 14, 2022, 10:56:39 amThe whole industry is full of word salad, sorry if my word salad is unintelligable turbo encabulator.Do people still call it an "inverter" what you use power your caravan - or mobile house or whatever.(From say a car battery -> house type power.)I was just wondering if you can use a 60hz spark gap oscillator for it, its still ac power the same, just the waveform is different.wouldnt any oscillator do?

author: Zero999
author_rank: Super Contributor
timestamp: January 14, 2022, 12:30:05 pm
content: Quote from: Capernicus on January 14, 2022, 11:40:51 amWhat's it?If you're talking about using a spark gap oscillator, as a mains inverter, then no.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 14, 2022, 12:36:22 pm
content: Why not, mr zero nine ninety nine?

author: TimFox
author_rank: Super Contributor
timestamp: January 14, 2022, 02:41:34 pm
content: Spark-gap oscillators produce an evanescent waveform, not a continuous sine wave.This goes back to Marconi.

author: Zero999
author_rank: Super Contributor
timestamp: January 14, 2022, 02:43:00 pm
content: Quote from: Capernicus on January 14, 2022, 12:36:22 pmThe mains is a sinewave.A spark gap gives a very nasty wavefrom, consisting of brief pulses, rich in harmonics. You might be able to get away with powering purely resistive loads such as incandescent lamps and heaters, but you'll get into trouble with the authorities for spewing out nose all over the radio spectrum.Some cheap inverters use a modified sinewave, which is bad enough, but still better than a spark gap oscillator.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 14, 2022, 04:24:02 pm
content: if its just going into an ac->dc converter (its dc anyway), what difference does it make.what if you can actually just power them with dc (like a computer) - and it doesnt bother the power supply?if its ac equipment, then maybe u do need the sinewave, but even then it could still work.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 14, 2022, 05:35:19 pm
content: Do they supply 3 phase power to residential area?

author: IanB
author_rank: Super Contributor
timestamp: January 14, 2022, 06:04:42 pm
content: Quote from: BeBuLamar on January 14, 2022, 05:35:19 pmI'm not sure what you are asking here?For example, in the UK, the 11 kV MV distribution supply predominantly goes all the way to three phase substation transformers, that produce a 240/415 V three phase LV output. This LV three phase output then goes in trenches under the street, or on poles beside the street, to the houses. Usually each house gets one of the 240 V phases, so that all the phases are evenly distributed. Larger commercial premises or offices likely get all three phases and then distribute them inside the building.In rare and isolated rural situations, a single phase of the 11 kV feed may run to a single phase pole transformer, producing a single phase 240 V output. But this will not happen in any large population center.By the way, the UK, Europe and many other parts of the world do not have the rigid American zoning concept of "residential" areas. Zoning is much more mixed, with houses, shops, offices, light industrial and commercial all intermingled.

author: IanB
author_rank: Super Contributor
timestamp: January 14, 2022, 06:10:03 pm
content: Quote from: Zero999 on January 14, 2022, 10:56:39 amWhat about electric showers and instant on water heaters? They can be 10 kW or more, which is already over 40 A just for that one load?

author: Zero999
author_rank: Super Contributor
timestamp: January 14, 2022, 06:53:52 pm
content: Quote from: Capernicus on January 14, 2022, 04:24:02 pmAnd the noise will cause interference, especially in the analogue parts of the system, such as sound.Quote from: IanB on January 14, 2022, 06:10:03 pmThey're not as common, as in the US. I have an instant water heater in my house, fuelled by natural gas. My parents have a power shower. The heat is provided by the same natural gas fuelled boiler which also provides hot water to the whole house and electricity just powers the pump.

author: IanB
author_rank: Super Contributor
timestamp: January 14, 2022, 07:23:12 pm
content: Quote from: Zero999 on January 14, 2022, 06:53:52 pmIt's been my experience that instant electric showers are really quite common in the UK:https://www.homebase.co.uk/bathrooms-plumbing/bathrooms/showers/electric-showers.listEspecially for retrofits in older bathrooms that did not have showers originally, and when people add a shower en suite in the master bedroom.(I could observe that new build homes in the UK were constructed without showers even into the 80's)

author: John B
author_rank: Frequent Contributor
timestamp: January 14, 2022, 08:49:05 pm
content: Quote from: BeBuLamar on January 14, 2022, 05:35:19 pmHere at least it's quite common to have 3 phase to residential areas. In city areas it's typically specified based on the size of the house, especially if the house is older. A few decades back it would have been common in a larger house to have electric hot water, heating, and cooktop / oven, not to mention incandescent lighting. Smaller, lower cost homes are usually single phase.Nowadays it's probably more common to gravitate towards single phase as there's an emphasis on moving away from those old energy guzzling households.Newer large-lot rural-residential blocks are typically 3 phase to account for both house and shed equipment. Proper rural is usually the worst - single phase on long thin lines. Outages are common and slow to fix, so many people have some form of solar, battery and inverter to augment.

author: David Hess
author_rank: Super Contributor
timestamp: January 14, 2022, 09:53:29 pm
content: In the US it is common for residential lots to be allowed *only* 240VAC split phase, with 3-phase service forbidden by law. Presumably this helps keep industry out of residential areas.

author: Zero999
author_rank: Super Contributor
timestamp: January 14, 2022, 10:44:47 pm
content: Quote from: IanB on January 14, 2022, 07:23:12 pmYes they exist and the ones I've used are pretty crappy, but they're hardly the norm. My parents house didn't have a shower either and when they got one installed, it had to be connected to the hot water system, as is the case for most showers in the UK.

author: IanB
author_rank: Super Contributor
timestamp: January 14, 2022, 11:00:57 pm
content: Quote from: Zero999 on January 14, 2022, 10:44:47 pmSure, but here's the thing. If your house had 40 A service, and you ran one of those showers, while also turning on the electric oven, while also boiling the kettle, you would far exceed 40 A. Even 60 A would be limiting.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 14, 2022, 11:50:52 pm
content: Quote from: IanB on January 14, 2022, 06:04:42 pmI mean if I want to operate equipment that requires 3 phase power can I have 3 phase power in my house?

author: themadhippy
author_rank: Super Contributor
timestamp: January 15, 2022, 12:16:48 am
content: Quote6kw shower,was the most common size before everybody wanted water jets that would both scalded you and pin you to the wall ,add in another 2kw for the oven,3kw for the kettle ,and another kw for the lights and telly,so 12kw ,or around 51A. A 40A BS88 or BS1361 fuse will let that pass for long enough to finish your shower and let the kettle boil.

author: IanB
author_rank: Super Contributor
timestamp: January 15, 2022, 12:43:06 am
content: Quote from: themadhippy on January 15, 2022, 12:16:48 amI have direct experience of those showers, and you want as much power as you can get if you don't want either a lukewarm shower or a feeble flow. 8.5 kW is the lowest you see on the market, and 10.5 kW is common and preferable.So 10.5 kW for the shower + ~5 kW for the oven (it has its own dedicated 32 A circuit) + 3 kW for the kettle plus 1 kW for other loads, that gives you over 80 A.That's peak load of course, probably not gonna happen all that often, but I think it should be something the supply can cope with.

author: IanB
author_rank: Super Contributor
timestamp: January 15, 2022, 01:05:32 am
content: To illustrate the electric shower weakness, consider that a comfortable shower should have about 9 litres/minute of water flow. If we suppose that water needs heating from 15°C to 50°C, then the power requirement becomes:Power = (9/60) kg/s * 4.2 kJ/kg/°C * (50°C − 15°C) = 22 kWIf the power is limited to 10.5 kW, the water flow will be limited to about 4 l/min, which is a fairly feeble shower.It is unfortunate, but electricity really doesn't cut it for instant water heating. For reasonable water flows you need gas.Brainwave!We could use a three phase supply!If we had 415 V three phase and we want 22 kW, we only need about 17 A per phase. That must be why homes in much of Europe have a three phase supply. It makes high power loads much easier to accommodate.

author: themadhippy
author_rank: Super Contributor
timestamp: January 15, 2022, 01:58:39 am
content: QuoteMaybe in the American shops but over here 7.5kw is readily available.Quoteseparate ring and ovens are a pretty new concept here,combine cookers are much more common,so that 32A not only has to run the oven it also feeds the 4 ringsQuoteyou'll be lucky,1.5-2.5kw is more likely due to numptys falling for energy efficiency lie.

author: IanB
author_rank: Super Contributor
timestamp: January 15, 2022, 02:16:57 am
content: Quote from: themadhippy on January 15, 2022, 01:58:39 amI've no clue what's available in the USA, I'm British. I posted the link to HomeBase above, and 8.5 kW is the lowest power they have listed. Most are higher.QuoteIf you are cooking dinner you will likely have the oven on and also have rings on for saucepans. Any modern home maker will also have a dual oven.QuoteI buy 3 kW kettles routinely, so I beg to differ. Most regular kettles are 3 kW "fast boil" except for really expensive, flashy ones.(Why I have to keep buying new kettles is another story.)

author: IanB
author_rank: Super Contributor
timestamp: January 15, 2022, 02:33:15 am
content: Also, American plumbing, heating and hot water systems are totally, utterly different from British systems. Where showers in Britain were always a novelty in British bathrooms and only got introduced relatively recently, showers in America have been a standard fixture for probably a century.By the way, I showed the power calculation above. 7.5 kW will give you a flow of about 3 l/min, which is pretty much like showering under spray bottle. It's not something that qualifies as a reasonable showering experience.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2022, 11:14:15 am
content: Quote from: IanB on January 15, 2022, 01:05:32 amThe other day, I helped a friend out with some electrical work in his apartment, and the main fuses for his unit (that is, at the panel where the meter is) are 25A per phase, three phases. For a two bedroom apartment.The downstream breakers at the panel inside the unit were smaller, of course. As far as I can tell, the only large loads are the stovetop and oven, which probably totals around 10-15kW.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2022, 11:29:05 am
content: Quote from: IanB on January 15, 2022, 01:05:32 amI think your assumed temperatures are a little off. You wouldn’t want 50C flow, since that’s a temperature that causes scalding within minutes. (Many modern shower mixers have an (overridable) limiter at around 40C, which is a pleasant hot shower.)Cold water can also come in much cooler than that, at least in northern climates like much of Europe. Here in Zurich, the cold water varies from 17C all the way down to 5.5C, with an average of 9.3C. (Most of Zurich’s water is drawn from the depths of the lake, where the water is right around 9C all year round.)So your 22kW heater would just barely work in the dead of winter to heat to a comfortable temperature. But in warmer seasons, it would have capacity to spare. The 10kW one would indeed be useless here in winter, in summer probably just barely tolerable. :p

author: Zero999
author_rank: Super Contributor
timestamp: January 15, 2022, 02:14:49 pm
content: Quote from: IanB on January 14, 2022, 11:00:57 pmYou're missing the point.One doesn't need an electric shower in the UK. A shower connected to the centralised natural gas fired boiler, is far more common. Natural gas is much cheaper here than electricity. It makes no sense to have am electric heated shower, unless there is no gas supply, in which case the building will have a higher current feed.I have an instant natural gas fired boiler for hot water. My cooker only uses electricity for the oven and grill. The hobs are all gas. I could probably get away with a 25A feed and not have any problems with nuisance tripping.Heck, when I as a child, my parents had a gas cooker and no toaster or microwave. The only high powered electrical item was the kettle. Their electrical power consumption probably topped out at around 15A. Now they have a microwave, toaster deep fat frier and electric oven (the hobs are still gas), but they never use them all simultaneously, so I doubt it goes much over 25A.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 16, 2022, 10:51:24 am
content: Isnt the power supply only 10A max?

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2022, 11:10:11 am
content: Quote from: Capernicus on January 16, 2022, 10:51:24 amWhat power supply?I'm talking about the amount of current drawn by the whole house. As mentioned above, most UK homes have a 100A fuse, which is more than enough. Some smaller, older houses only have 40A, which is also fine, as long as they don't have an electric instant hot water heater, such as a power shower, which isn't necessary, as long as they have natural gas available.

author: IanB
author_rank: Super Contributor
timestamp: January 16, 2022, 11:13:29 am
content: In today's world, there is also EV charging to consider as a potential large load.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2022, 11:39:27 am
content: Quote from: IanB on January 16, 2022, 11:13:29 amhttps://www.eevblog.com/forum/beginners/house-outlet-ac-power/msg3939964/#msg3939964Another problem with EVs is not everyone has space to install a charger, but that's way off-topic.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 16, 2022, 12:49:08 pm
content: Quote from: Zero999 on January 16, 2022, 11:10:11 amYeh, I thought it was 10A for the whole house!!! isnt it only 2400 watt max allowance??Oh... do you mean transforming it for more amps?

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2022, 01:05:26 pm
content: Ev charging isn't really the problem some make out,many chargers will monitor the current demand of the property and limit the charge,also theirs the option of charging overnight when your demand is low.Theres also the option of putting in priority switching so your EV charger gets turned off when you turn on your shower.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2022, 01:35:05 pm
content: Quote from: Capernicus on January 16, 2022, 12:49:08 pmNo, you can't increase the current.Quote from: themadhippy on January 16, 2022, 01:05:26 pmYes, I thought about that after I posted. Flexible electricity prices also provide an incentive for people to charge at night.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 16, 2022, 01:38:43 pm
content: 240V 1*40A is not much worse than the Finnish standard, 230V 3*25A. 75A total remains pretty theoretical because balancing the loads that closely is impossible; whereas in single phase system you can utilize the full current no problem.Yet, all electric heating is usual in many such 3*25A houses. This typically means 3kW (3*4.3A) in hot domestic water buffer tank, and around 10kW peak (3*14A) for heating. If and when they happen to work simultaneously, that leaves some 3*6A foreverything else, and that everything else is impossible to get balanced (typical stoves have two "burners" in one phase, two more in the second one, and the oven in third. Turn the wrong two on at the same time, and you are doomed).This arrangement working at all relies on the fuses being really slow and often/typically not blowing until In * 1.4 or something, and people replacing blown fuses. A crappy system. Depending on where you happen to live, upgrade to 3*35A is either free, or prohibitively expensive. Because 3 phase does not have any function in the modern day in itself (since the proliferation of VFDs), having 3-phase forced down to households is only a nuisance. Having whole houses with 1*75A would be superior in every regard (including averaging out better on grid level), except if you really want to run some old industrial lathe you got for cheap and don't want to invest $500 on a VFD.

author: themadhippy
author_rank: Super Contributor
timestamp: January 16, 2022, 01:51:33 pm
content: Quotejust wap a transformer on yer 3 phase incomer with a single 230v output ,added advantage neither leg of your 230v supply will be referenced to ground

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 16, 2022, 01:59:11 pm
content: Quote from: Zero999 on January 16, 2022, 01:35:05 pmWhat about a step up transformer?

author: TimFox
author_rank: Super Contributor
timestamp: January 16, 2022, 03:11:12 pm
content: Step-up transformers increase the voltage anddecreasethe current.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 16, 2022, 03:15:00 pm
content: step down i mean.

author: TimFox
author_rank: Super Contributor
timestamp: January 16, 2022, 03:26:10 pm
content: Obviously, that reduces the voltage. Neither type of transformer will increase the power.

author: Zero999
author_rank: Super Contributor
timestamp: January 16, 2022, 05:52:53 pm
content: Quote from: Capernicus on January 16, 2022, 03:15:00 pm

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 17, 2022, 01:42:52 am
content: playing the fool, is something i dont understand, i am sorry.so what do we do, just lie to all the kids at uni?

author: Monkeh
author_rank: Super Contributor
timestamp: January 17, 2022, 02:35:47 am
content: Quote from: Capernicus on January 17, 2022, 01:42:52 amWhat on earth are you on about?

author: Munyua44
author_rank: Contributor
timestamp: January 17, 2022, 04:43:49 am
content: i would advice you have a look at the basics about electricity. We have too much information on the internet that will allow you to understand why some countries settle for 120v and others 240 v

author: Zero999
author_rank: Super Contributor
timestamp: January 17, 2022, 08:47:13 am
content: Quote from: Capernicus on January 17, 2022, 01:42:52 amMentioning a step-down transformer, to increase the current, was silly because you know it reduces the voltage, which again is silly, because it's important to keep the voltage the same 230V.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 17, 2022, 10:44:18 am
content: If your house only have 2400W like someone said you're in big trouble.

author: grumpydoc
author_rank: Super Contributor
timestamp: January 17, 2022, 11:19:46 am
content: Quote from: BeBuLamar on January 17, 2022, 10:44:18 amEDF in France go down to a 3kW supply agreement.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 17, 2022, 11:42:17 am
content: Quote from: Capernicus on January 09, 2022, 09:06:27 pmNot so much to do with phase as they are different parts of the same waveform, but it is because they are not coincident in time.If you boil your kettle, it doesn't care if the current through its element flows one way, then the other, it is only the heating effect that is important.The heating effect is directly related to the power dissipated in the element.The following is a "mind exercise", only.You won't be set up to do it safely in real life, as it requires a High voltage DC supply capable of supplying around 3kW of power----a very rare device in any home lab.Using your nominal 240v ac Mains supply, if you boil a quantity of water, time how long it takes to boil, then let the kettle cool right down to cold, then supply a DC voltage to the kettle of the same nominal voltage, the water will boil in the same time, so obviously the "240v ac" supply is equivalent in work done to the 240v DC supply.The normal approach to this is mathematical, but the "Empirical" approach above may help to visualise why we use RMS!

author: tooki
author_rank: Super Contributor
timestamp: January 17, 2022, 12:38:00 pm
content: Quote from: Capernicus on January 17, 2022, 01:42:52 amYou really, really, really need to erase everything you think you know about electricity, then start learning electricity basics from the beginningsystematically. Your half-understandings, with the gaps spackled over with little more than bravado, are doing you — and everyone else — a disservice. You cannot properly learn when your fundamentals are so mangled.

author: JohanH
author_rank: Frequent Contributor
timestamp: January 17, 2022, 01:35:43 pm
content: Quote from: Siwastaja on January 16, 2022, 01:38:43 pmI've never had any issue with 3*25A. But I have never had all electrical heating either. Ground source heat pumps are becoming common. That reduces electrical demand. My own pump has three phase connection, but the compressor itself uses one phase (variable speed three phase BLDC motor inside). Motor is max 2 kW, so no issues (6.5kW max heat output). Of course, it does have electrical coil heaters as backup on the two other phases, but they are almost never used. The largest single consumer is the 3-phase sauna stove (6 kW). Electrical car chargers might benefit from larger current, but I'm afraid it won't be less expensive in the future to upgrade from the most common 3*25A.

author: mcz
author_rank: Contributor
timestamp: January 17, 2022, 02:36:47 pm
content: Quote from: Siwastaja on January 16, 2022, 01:38:43 pmWell the problem is that running 1x75 Amps requires you to have 2x16sqmm (total 32sqmm) copper wire while 3x25A requires you to have 4x4sqmm. (total 16sqmm)The ratings are from a table and for buried cables underground. For real we obviously need to consider and calculate voltage drop along the lines.But it is very well know that 3 phase power delivery is cheaper than single phase for a given power. Which is why it is used everywhere around the world for power transmission.In the end you get 17.3kW total while the british 40A single phase is just 9.6kW. That's pretty close to half the power. I think the culprit is not your 3 phase power but the fact that your electrical supply is underrated for heating houses with electricity.Just for comparison I think I've currently got 3x50A coming in an you can get 3x63A here for no additional cost. But I haven't had that discussion with the electrical service provider. And most homes here (>90% if I had to guess) use gas/oil furnace for heating.edit: changed cable calculation

author: Siwastaja
author_rank: Super Contributor
timestamp: January 17, 2022, 05:41:26 pm
content: It's a bit of apples vs. oranges comparison, because with 2x16 mm^2 you get more, i.e., the ability to run larger single-phase loads, or unbalanced loads. The whole point is, you can't get 75A total out of the 3*25A system, so actual A / mm^2 is not twice (it's still somewhat better, of course).You also missed the fact that 4x4mm^2 doesn't suffice and is illegal. Neutral wire needs larger dimensioning. So the calculation is just outright wrong; a good example how 3-phase power is confusing. (See zero sequence harmonics.)The real solution to the problem obviously doesn't involve a transformer, but simple current transformers & contactors that cut heating temporarily (most simply, just all three phases, or even better, just one phase at the time, the one going overcurrent). Not a new invention, but nevertheless some extra cost.Power distribution is 3-phase everywhere, including countries (UK, USA) where houses tend to be single-phase. It averages out very well because the neighbor will be in a different phase. It likely averages outbettercompared to a situation where we have 20 identical houses, built around same time, wired by the same electrician so that the oven is always in the same phase.With the government subsidy to replace oil burners with air-source heatpumps, which transition into electric heaters at coldest weather to the surprise of the user who were not told about this by the marketing, this 3*25A limitation is becoming as a surprise for many; especially if the load balancing between phases was never considered because there was no need when both heating and domestic hot water was supplied with the burner. Margin in fuses mitigates the problem. If you actually monitored phase currents, you would be surprised how many households regularly and significantly exceed their nominal fuse ratings, being pretty close to actually blowing the fuses but just not barely getting there. This is not the intended way of operation for wiring and fuses, BTW.Add to this our "16A rated" plugs that supposedly melt at 16A and need to be limited by legislation to 8A when charging EVs, instead of fixing the plug ratings, and we have a pretty crappy last-mile + household electrical system compared to the Brits and their excellent massive, fused plugs + switched outlets!

author: IanB
author_rank: Super Contributor
timestamp: January 17, 2022, 05:56:46 pm
content: Quote from: Siwastaja on January 17, 2022, 05:41:26 pmI was just thinking about this today. With gas prices going through the roof, the future may see a pivot towards electricity and renewable energy. I think the UK government may even be considering a mandate for heat pumps in new builds. That's going to change the perspective on how much electricity is supplied and used.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 17, 2022, 06:00:09 pm
content: Quote from: IanB on January 17, 2022, 05:56:46 pmYeah, well for us here, the incentive has been always there and is purely economical, because energy price have had near 1:1 parity between electricity and burnable fossils, thanks to cheap electricity and heavily taxed fossils; causing the COP of the heat pump to translate into money savings almost directly. This is one of the few things we have the right way here, IMHO. The fact that in UK or US you get natural gas (or even oil) for so much cheaper than electricity per kWh, that installing heat pumps makes no financial sense, is just... nuts. Especially since the conditions for air source heatpumps would be just excellent in the UK. We run 'em here even though they are pretty marginal, and theystillmake financial sense... or made, before the subsidies caused hyperinflation in their install prices.

author: themadhippy
author_rank: Super Contributor
timestamp: January 17, 2022, 06:10:24 pm
content: Quotesort of,from 2025 gas and oil boilers wont be allowed in new builds.

author: mcz
author_rank: Contributor
timestamp: January 17, 2022, 07:06:07 pm
content: Quote from: Siwastaja on January 17, 2022, 05:41:26 pmThe conductor thickness comparison was mostly an exercise to illustrate how much more copper is needed for those higher currents. It is a lot. (P=I²*R losses)Yeah, heavy single phase supply might be nice for you (while I prefer to be able to run 3ph stuff) but it is coming in at a cost.And what matters in the end is that I can run 17.3kW both from the 3x25A and from 1x75A. Now if that works out in the end depends on the application. We usually calculate with upwards of 30kW supply necessary for electrically heated homes over here.Pretty sure my incoming cable is a 4x10sqmm copper one. I don't know what legislation would require a bigger neutral but I certainly don't have one. Most residential or even commercial use is not going to run old servers with no PFC and heavy harmonics. And the industrial heavy equipment is mostly 3 phase with no neutral connection. However, your mileage may vary.I really don't see the point of running larger single phase loads.. I simply haven't found any as those large loads usually tend to be 3 phase.

author: Gyro
author_rank: Super Contributor
timestamp: January 17, 2022, 07:16:39 pm
content: Quote from: themadhippy on January 17, 2022, 06:10:24 pmAlthough the boiler industry is planning to be fully Hydrogen ready by 2024 - I hope to nurse my cast iron one along until then.... but I digress, let's not go there in this thread.

author: bdunham7
author_rank: Super Contributor
timestamp: January 17, 2022, 07:17:25 pm
content: Quote from: Siwastaja on January 17, 2022, 05:41:26 pmAre the electric heating loads typically phase-to-phase or phase-to-neutral??

author: Siwastaja
author_rank: Super Contributor
timestamp: January 17, 2022, 07:25:51 pm
content: Quote from: mcz on January 17, 2022, 07:06:07 pmI can see it was an exercise, but clearly an incorrect one which is why I corrected you. Obviously higher current requires more copper, there is no way around this. This is not related to 1-phase vs. 3-phase. Your example supposedly showed that 3-phase requires lower mm^2per A- in other words, better utilization - but I showed that your calculation is incorrect, and now you just changed the goalpost to match the reality that the 1-phase 75A use case actually carries more current, which is indeed true.If you need x A, then you need x A. Single-phase system has optimum copper use, since the current in incoming conductor and return path is always automatically equal.Perfectly balanced 3~230V equals 1~400V system regarding losses, AFAIK, so it does a bit better. But you could as well use the 400V in a single phase system, or do what our US. of A friends do and use a center-tapped transformer to power "small" trivial loads with lower voltage, and big loads with higher.3-phase is excellent for large-scale distribution and motors, but what it doesnotoffer is good copper utilization in residential wiring.In other words, in 3*25A nominal systems it's completely possible and usual that some of the wires carry 30-35A (beyond the design current) while the total is still just say 50. This leads topoorcopper utilization. While in 1-phase house wiring, copper utilization is always optimal and geez, if you don'tneed75A, then don't wire for 75A.Now I understand where your confusion is coming from: "3-phase distribution has good copper utilization" is a widely touted claim, because it is true. But you need to understand the scope of this claim. It applies to distribution at wide scale, where balancing the phase currents is well possible; this enablescomplete eliminationof the neutral wire - or utilizing the Earth as neutral - or using very undersized neutral wire.But at small scale, this completely turns around; due to heavily unbalanced loads and zero sequence harmonics, neutral wire has to be dimensioned larger than phase wires (or, all conductors are just regularly overdimensioned).Another strong reason for the 3-phase distribution are naturally 3-phase generators, and large 3-phase motor loads in the industry. But again, 1) this does not apply to households, 2) this is slowly changing.Third reason for the "3-phase is superior" claim is that this still lives from the days when it was compared to a 2-phase system (not split-phase; 2-phase with 90deg phase shift). This discussion was relevant over 100 years ago, but back then 3-phase system offered zero neutral conductor current in a motor, while 2-phase system had double the neutral conductor current. Tesla knew what he was doing!But Brits and Americans are not stupid in their 1-phase house wiring scheme. It is used because it is superior. Our inferior system leads into stupid compromises like manufacturers not willing to design 3-phase loads (theyaresignificantly more complex) and instead design 400V single-phase loads to be connected between two phases, which allows at least to extract 2/3 of the available current without causing massive imbalance. Examples of such systems are some Scandinavian water heaters, and most EVs which come in Europe with a 3-phase plugs, but only utilize 2 of the phases, causing unbalance and arbitrarily limiting their charging power. But 3-phase design would have been prohibitively expensive. No such issue if the house was just 1-phase to begin with.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 17, 2022, 07:27:31 pm
content: Quote from: bdunham7 on January 17, 2022, 07:17:25 pmIn Finland, usually phase-to-neutral, meaning that all significant heaters are built out of three distinct resistors connected in wye, with neutral also connected. In some other Scandinavian countries I think delta wiring is usual, including the typical case of only having one heater between two phases, allowing 2/3 utilization with simple, single heater. (Single-phase system would allow 100% utilization, though).So basically it's surprisingly common to use the 3~230V system as a 1~400V system which can output more power simply thanks to higher voltage. Designers of such devices (heaters and EVs) prefer to design single-phase loads!

author: JohanH
author_rank: Frequent Contributor
timestamp: January 17, 2022, 07:59:11 pm
content: Quote from: Siwastaja on January 17, 2022, 06:00:09 pmOne thing I've experienced, is that air source heat pumps are not well suited here up north. In the past the house was heated with an oil burner and eventually I also installed an air heat pump, which made it much more comfortable inside, but didn't save much oil. Now four years ago, I ditched the oil burner and installed a ground based heat pump. I pretty much have the same electrical bill as before, but no oil bills! That's because of the much higher efficiency of the ground based heat pump system.But in places where the weather tends to stay above say -5 ℃, I would imagine air source heat pumps work good and are of course cheaper to buy and install.

author: bdunham7
author_rank: Super Contributor
timestamp: January 17, 2022, 09:00:10 pm
content: Quote from: Siwastaja on January 17, 2022, 07:25:51 pmThat there is the issue that demarcates the dividing line between where 3-phase is the way to go and where it is not. Distribution? Yes! Large motors and very large other loads that are economically viable to design in 3-phase? Yes? Toasters, water heaters and home HVAC? Not so much, especially with the availability of modern PFC/VFD and inverter-drive technologies. Even the data-center neutral issues with harmonics would have been a non-issue if they weren't trying to use piles of just-above-consumer level single-phase PSUs in a phase-to-neutral configuration.Even home EV charging is really better done with 1-phase, IMO.

author: Zero999
author_rank: Super Contributor
timestamp: January 17, 2022, 10:00:18 pm
content: Quote from: Siwastaja on January 17, 2022, 06:00:09 pmHow is it nuts?A good proportion of our electricity is generated using natural gas and other fossil fuels, so it's obviously going to be more expensive, than gas. Electricity being the same price as gas makes no sense. It's like in the USSR when bread was cheaper than grain, at one point, so farmers fed it to their animals. This just shows the insanity of too much state interference in the market.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 18, 2022, 08:25:07 am
content: Quote from: Zero999 on January 17, 2022, 10:00:18 pmBecause if you turn natural gas into electricity in modern combined cycle facilities and use at least some of the waste heat for district heating with combined total efficiency of, say, 60% (this is a fair approximation, much better numbers have been reported), and then use this 60% to run heat pumps at COP=3, total efficiency (from chemical energy in gas, to heat output inside houses) is 180%. Add renewables to the mix and it only gets better. This is why.The point you totally miss is extracting free energy. It's similar to PV; the only reason not to install it is, if install costs exceed the savings. Artificial market structures like super-cheap fossils and expensive electricity affect that natural balance of energy choices which should be based on minimizing burning fossils and maximizing extraction of free energy.This is, if bread was miraculously falling off the sky, it would make sense to feed it to animals, even if small amount of effort would be required to collect and distribute that bread.If you think it from climate viewpoint, price should be in relation of the CO2 emissions per kWh. The emissions from grid energy are roughly similar to that of locally burning natural gas. (Roughly, because it's really a moving target). Hence the price should be similar. Not exactly the same, but 3x difference in favor of burning fossils is, I repeat, just nuts.If natural gas is three times cheaper per kWh than electricity, this leads tomassive waste of energydue to ignoring heat pumps, which could provide a lot of basically "free" energy.Finland's tradition of similar price per kWh between fossils and electrical energy (which, on average, has lower CO2 footprint than locally burning fossils) is not only logical and fair, it leads into natural incentive to make energy efficient choices. Now this is partially thanks to the nanny state which I pretty much hate, and we have many of those USSR-like sick mechanisms you mention, but approximate energy price parity is not one of those; this is one of the very few areas where the system accidentally succeeded. Maybe because no one has thought about it, it's not planned, it's more of a coincidence.Also don't underestimate the amount of politics that went into the cheaply available natural gas! It's an indirect incentive as well. That is the part I callnuts.Similarly, some countries have sources of cheap oil available to them thanks to political choices of extracting it, or starting wars to gain access to it. We never had this kind of source.Quote from: jukk on January 17, 2022, 07:59:11 pmHere in the Southern parts it works fine, but I do switch to oil, below approx. -17 (when COP < 1.5). Still, one of the most important things overlooked by those installing air-to-water units is the total surface area of the distribution (radiator size, or in-floor heating vs. not having one). It completely changes the game. If you need to run 60degC water into the system at mere -10degC, you can't win. Even ground source would struggle to give good savings but it at least somehow works. But the whole game changes if you run 30degC water in massive radiators or in-floor heating. I invested 3000€ in the heat pump and another 600-700€ into upgrading radiators and it's working well and based some modeling and approximate measurements I'm expecting SCOP significantly exceeding 2. The radiator upgrade pays for itself in a year or two. Such "small" details are hugely important.

author: mcz
author_rank: Contributor
timestamp: January 18, 2022, 09:21:08 am
content: Quote from: Siwastaja on January 17, 2022, 07:25:51 pmWell, in the end it is a certain amount of power that is heating your house/water, not current.If we assume for simplicity and easy comparison that your 75A circuit is 3 times a 25A single phase coming in (and it is the same phase) that just gets paralleled that gives you 6 times a conductor of a certain size.The according 3-phase system (at the same power -> 3x25A but 3 phases) gets rid of 2 return paths leaving you with just 4 wires of the same size. And again, no bigger sized neutral in use here.Whether you use the available power is up to you. Just because in your example the 25A rating is particularly shitty doesn't mean the concept as a whole is bad.

author: JohanH
author_rank: Frequent Contributor
timestamp: January 18, 2022, 09:44:26 am
content: Quote from: Siwastaja on January 17, 2022, 07:25:51 pmMaybe farming and industrial needs have influenced the shift to 3-phase here. I remember in my youth, a lot of farmers installed electrical motors for dehydrating grains, conveyors etc. I remember one particular example on a farm where the 3*60A main fuse sockets always expanded due to the high current and eventually began sparking and then popped a fuse. It was solved by changing to industrial grip type fuses. This particular motor was so big so it could be seen around the village when they started it (every evening), due to the lamps always dimming a bit. That again was solved by a larger distribution transformer in the village. There were single phase connected houses here in the past, but I haven't heard of any with larger than 25A mains. The "upgrade" that was offered was always 3-phase, not larger mains fuses.Now the 3-phase heat pumps have been in a bit of bad situation because of the situation you describe. I've read many examples of their inverters going bad due to one phase breaking in the house. Solution for those would be larger mains fuses and/or phase protection at the pump that breaks all phases if one goes missing. So actually I'm glad I get by with a one-phase compressor, less troubles.

author: JohanH
author_rank: Frequent Contributor
timestamp: January 18, 2022, 10:02:19 am
content: Quote from: Siwastaja on January 18, 2022, 08:25:07 amYes, I upgraded radiators as well when switching from oil to ground heat pump (the bigger the better). In-floor heating would be best, but this is an old house, so not that easy to convert. Now it gets to 55-60 ℃ at -25 ℃, so kind of fine. Those temps are rare, but happens about once per winter.Some statistics I've checked/calculated from the heat pump:COP 4.4 at 0 ℃. Heat output 2.4 kW, electrical power 0.54 kW.COP 3.9 at -15 ℃. Heat output 4.5 kW, electrical power 1.16 kW.(this must be momentary numbers, my notes are a bit messy)With a newer house with better insulation and only in-floor heating, those numbers would be better.Edit. Looked up my notes and it looks like SCOP improved from 3.2 to 3.7 due to the larger radiators. In 2021 SCOP was 3.7. These numbers are quite reliable, because I've a separate energy meter at the pump and the pump itself has its own flow sensor, calculating total heat output.

author: nali
author_rank: Frequent Contributor
timestamp: January 18, 2022, 10:09:52 am
content: Quote from: Siwastaja on January 17, 2022, 06:00:09 pmWell in the UK there is a masive disparity between domestic gas & electricity prices. A quick look at my last year's bills which is a standard domestic tariff* gives gas:3.3p electric:19.7p per kWh which even at optimal CoP makes it more expensive to run. Add to that the cost of installation means there's simply no incentive to retro-fit.There is a govt grant to offset installation, but you need to use an approved installer (expensive) so expect to pay a 5-figure sum.*(We're planning moving house so not much point signing up to new tariffs just now. I do want to move to heatpump but I'll evaluate that as part of the whole package when housemoving)

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2022, 10:45:48 am
content: Quote from: Siwastaja on January 18, 2022, 08:25:07 amYes it's more environmentally friendly to use a heat pump, but it's more expensive. The fact that gas has to be taxed to make the price equal to electricity in your country proves this. I'm all for cutting CO2emissions, but I'm against everyone being poorer and higher taxes more. If the UK achieved net zero CO2emissions tomorrow. It would make absolutely sod all difference to the global climate, with Russia, China and the US emissions dwarfing the UK. The only people who would benefit is our big fat government.I wonder if gas powered heat pumps would be a better alternative, assuming they're a thing? The installation cost would be high, but they're bound to be more efficient.

author: SeanB
author_rank: Super Contributor
timestamp: January 18, 2022, 12:02:13 pm
content: Rural single phase is very common, SWER means you only have to run a single bare 11kV overhead aluminium conductor, and put the transformer by the load, and add in the big earth mat under the transformer, with the secondary having a separate earthing rod a few metres away. Thus you find there being a product from Alsthom in supplying a single phase 22kW motor, which is a common item to use, as 63A is about the largest load you can get off the most common cheap rural tariff, for a 15kVA supply, and not needing a supply conductor upsize.3 phase yes is cheaper in conductor if you only consider conductor size, but if the supply also means you need 3 conductors installed, instead of one, then single phase is cheaper for rural use, especially as there is no difference in conductor size at 11kV.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 18, 2022, 06:52:24 pm
content: Quote from: grumpydoc on January 17, 2022, 11:19:46 amYou mean you can only have 3kW to power your house? Wow. I was thinking of getting a backup generator for my house and I think I need a 20KW unit to do that.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 18, 2022, 07:03:22 pm
content: Quote from: BeBuLamar on January 18, 2022, 06:52:24 pmI thought it was 10A for the whole house - before it starts to brown out. (or the safety goes off.)

author: JohanH
author_rank: Frequent Contributor
timestamp: January 18, 2022, 07:12:18 pm
content: Quote from: BeBuLamar on January 18, 2022, 06:52:24 pmWhat kind of house is that? Levitating? Just kidding. I think I would get by with a 3 kW generator (worst case). But that would mean no sauna or car engine heaters. We have about 2 kW continuous power consumption with short peaks of 6-7 kW in the winter. Total year consumption 16000 kWh. And I would imagine it's a typical house around here (maybe a bit on the smaller side).

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2022, 07:28:35 pm
content: Quote from: Capernicus on January 18, 2022, 07:03:22 pmDon't be silly. An electric kettle normally uses around 10A, which is 2400W, at 240V. In the UK, the maximum current per plug is 13A, which is roughly 3kW, although some appliances can draw a little more, for a short period.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 18, 2022, 09:42:14 pm
content: So its per plug, not for the whole house!!I didn't know that. So what if I get two plugs and power one thing off it, do i get 20A??

author: themadhippy
author_rank: Super Contributor
timestamp: January 18, 2022, 09:48:19 pm
content: QuoteTheoretically yes, practically you stand a very good chance of being dead

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2022, 09:54:39 pm
content: Quote from: Capernicus on January 18, 2022, 09:42:14 pmNo, the device will only draw as much current as it needs.Connecting two plugs together is very dangerous. Don't do it. If someone disconnects one of them, it will have mains voltage, on the exposed pins.

author: IanB
author_rank: Super Contributor
timestamp: January 18, 2022, 10:58:27 pm
content: Quote from: Zero999 on January 18, 2022, 07:28:35 pmThis is the second time I have seen this said recently. But if you go here, for example, the majority of listed products are 3000 W:https://www.currys.co.uk/gbuk/household-appliances/small-kitchen-appliances/kettles/336_3156_30244_xx_xx/xx-criteria.html3000 W is cunningly designed to max out a 13 A plug, since 3000/240 = 12.5.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 18, 2022, 11:28:49 pm
content: Quote from: Zero999 on January 18, 2022, 09:54:39 pmIt would be good to power a 120db block party rave out of your house tho. (with your custom amplifier.)

author: John B
author_rank: Frequent Contributor
timestamp: January 19, 2022, 01:03:31 am
content: It's called a Darwin extension cable.

author: themadhippy
author_rank: Super Contributor
timestamp: January 19, 2022, 02:07:38 am
content: QuoteWe call em widow makersQuotetry widening your shopping net,just like homebase aint the only seller of showers,currys aint the only seller of kettles,theirs plenty of kettles rated at 2-2.5kw as there are showers rated less than 8.5kw.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2022, 02:31:15 am
content: Quote from: themadhippy on January 19, 2022, 02:07:38 amWhy would I want to buy a kettle less than 3000 W? It will boil slower. It would be just as dumb as buying a shower less than 8.5 kW.But since you are taking issue, please show me a UK retailer of your choice where most kettles listedare not3000 W? You can pick Argos, Tesco, John Lewis, Amazon, any popular retailer of kitchen goods. Not just some of the kettles, most of the kettles.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 19, 2022, 07:58:58 am
content: Here in the European market of crappy Schuko plugs and some tradition for 10-16A fusing per whole circuit of outlets, kettles are typically around 1.5-2kW. I just checked mine, which is 1650W, but this isn't too bad if you are making just 1-2 cups of tea at a time. Visiting Japan, I remember kettles designed for the 100V plug and these were well below 1kW.Basically here, anything beyond 2kW does not come with a plug, but would require a permanent installation by an electrician!European stoves also tend to have lower power burners compared to UK or USA; if you want to actually fry something (instead of slow boiling), better preheat the pan on the stove for 3-4 minutes, and then fry small amounts at a time. It's not always like this, of course, higher power appliances are available, but you can't take the US-style 230V 40A stoves for granted. But we get by, laughing at the strawman of the USA supposedly being limited to 110V and no power beyond ~1kW anywhere.

author: Zero999
author_rank: Super Contributor
timestamp: January 19, 2022, 08:52:31 am
content: Quote from: IanB on January 19, 2022, 02:31:15 amI have a kettle rated to much less than 3kW. I think it's around 1kW, from memory. I like it because it's much smaller than my 3kW kettle and I can boil 1 cup of water.The main reason for having a low power kettle is for situations where there isn't much power available, such as when running it off an inverter, or at a campsite, where you might not have enough power available for a 3kW kettle.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 19, 2022, 12:53:59 pm
content: Many kettles suffer from poor ratio between min/max water volume. You need to boil 2 cups and waste half of the hot water. And when you get a few visitors and want to make 5 cups, you need to do it in two batches.I'm sure with clever design one could design a kettle which could boil you just one cup of water, but could also do 1.5 liters, and do all that with high peak power (say 3kW).

author: JohanH
author_rank: Frequent Contributor
timestamp: January 19, 2022, 01:20:37 pm
content: Quote from: Siwastaja on January 19, 2022, 12:53:59 pmInduction should solve this. A quick google search shows something like this:https://www.cnet.com/tech/computing/this-crazy-kettle-heats-only-the-water-you-need/

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2022, 02:57:16 pm
content: Quote from: Siwastaja on January 19, 2022, 12:53:59 pmI do currently own and use a 3 kW kettle with a capacity of 1.7 liters that also can boil one cup of water:https://uk.russellhobbs.com/adventure-kettle-23910I like it because it has no plastic windows that can leak.Quote from: Zero999 on January 19, 2022, 08:52:31 amGranted.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2022, 03:21:26 pm
content: Quote from: Siwastaja on January 19, 2022, 07:58:58 amOuch. That would be frustrating for anyone who likes cooking.I have a gas stove with literal burners, and out of curiosity I measured the heat output of a burner on the maximum setting a little while back. I found it was about 1000 W, which was lower than I thought it might be.

author: mcz
author_rank: Contributor
timestamp: January 19, 2022, 05:34:27 pm
content: Quote from: IanB on January 19, 2022, 03:21:26 pmInteresting. My dad has a gas stove and the bigger burners are rated 4.5kW. I think my (induction) stove burners go from 2.2kW max to 3.3kW max, depending on the size of the thing. Dunno what the US equivalents are.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2022, 06:33:28 pm
content: Quote from: mcz on January 19, 2022, 05:34:27 pm4.5 kW sounds very high, actually.What I did was compare the time to boil a liter of water on a stove top kettle compared to an electric kettle. Boiling on the stove top is very, very slow.Gas burners will not transfer all the heat to the pot, some of it is wasted round the sides. However, induction burners should be more efficient in that regard.You could try a test and see. At 3.3 kW it would take under 2 minutes to boil a liter of water.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 19, 2022, 06:35:33 pm
content: Quote from: IanB on January 19, 2022, 02:31:15 amMy house has 200A service here in the USA but I can't use a kettle of more than 1500W. My outlet is only rated for 15A and has breaker for 20A.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2022, 06:40:57 pm
content: Quote from: BeBuLamar on January 19, 2022, 06:35:33 pmYup, but if you are creative you can (have an electrician) wire a 240 V circuit from the panel to a NEMA 6-20 receptacle and plug a 240 V kettle into that

author: mcz
author_rank: Contributor
timestamp: January 19, 2022, 06:43:50 pm
content: Quote from: IanB on January 19, 2022, 06:33:28 pmYeah the thing (my dads stove) seems fast. And stuff can get pretty hot as well while with electric heating you don't really discolour a pan/pot that fast lol.Apparently professional gas stoves might run up to 11kW.Seems like a good idea to try out. The problems I see is that the pot itself has a significant thermal mass that might throw off measurements and actually bringing water near the boiling point means it evaporates and steals "a lot" (well, some) energy. But I guess I try it first.Quote from: IanB on January 19, 2022, 06:40:57 pmI think a fun approach would be to overclock the 120V kettle and run it on 240V. 4 times the power MIGHT just work... (disclaimer: this is dangerous!)

author: tooki
author_rank: Super Contributor
timestamp: January 19, 2022, 09:08:21 pm
content: Quote from: Siwastaja on January 19, 2022, 07:58:58 amA typical US burner is no more powerful than a European one. Some US stoves do have a jumbo-size burner, but it’s not universal.A standard US domestic circuit is 120V/15A. (It hasn’t been 110V for the better part of a century. It’s 120V/240V.) So 1800W, not the 1.1kW you claim. Still less than the 2300-3700W of many European circuits.

author: nali
author_rank: Frequent Contributor
timestamp: January 19, 2022, 09:39:26 pm
content: Quote from: mcz on January 19, 2022, 06:43:50 pmHere's some research material for you then

author: BradC
author_rank: Super Contributor
timestamp: January 20, 2022, 12:31:36 am
content: Quote from: nali on January 19, 2022, 09:39:26 pmNice!My wife is a Scot and loves a cup of tea. She wanted to know where she could get a kettle that could boil a pint in under 10 seconds. Given the "research" presented in that video if I wired one delta here I should get close to that. Somehow I suspect their source impedance might be a bit higher and fault current a bit lower than if I hooked it straight up to the grid.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 21, 2022, 12:29:44 am
content: Look at the size of that power plug.I wonder how much torque 10kW can deliver in an electromagnetic motor.

author: TimFox
author_rank: Super Contributor
timestamp: January 21, 2022, 12:34:35 am
content: Depends on the rpm.

author: IanB
author_rank: Super Contributor
timestamp: January 21, 2022, 03:04:07 am
content: Quote from: Capernicus on January 21, 2022, 12:29:44 amPfft. 10 kW is not very big. I'm just looking at the data sheet for an 18 000 kW motor. The full load torque is about 70,000 ft-lb, or 95 000 Nm.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 21, 2022, 04:01:17 am
content: Quote from: IanB on January 21, 2022, 03:04:07 amYou can turn the statue of liberty into a giant robot with that?

author: Siwastaja
author_rank: Super Contributor
timestamp: January 21, 2022, 10:23:59 am
content: Quote from: Capernicus on January 21, 2022, 04:01:17 amExcellent idea! I like your posts.

author: BradC
author_rank: Super Contributor
timestamp: January 21, 2022, 10:37:25 am
content: Quote from: IanB on January 21, 2022, 03:04:07 amThey don’t tend to be wired on a removable plug though.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 21, 2022, 12:49:03 pm
content: Quote from: IanB on January 21, 2022, 03:04:07 amI have a good working 30KW motor for sale cheap.

author: Zero999
author_rank: Super Contributor
timestamp: January 21, 2022, 01:49:00 pm
content: Quote from: tooki on January 19, 2022, 09:08:21 pmGas fired burners are often more powerful than electric stoves. The problem with a stove is lots of the heat isn't transferred to the pan. I believe induction hobs are more efficient, but they depend on the pan being made of the correct material.

author: tooki
author_rank: Super Contributor
timestamp: January 21, 2022, 09:45:15 pm
content: I can absolutely attest to the efficiency of induction. Both gas and traditional electric lose heat to incomplete transfer to the pan; in induction, the thermal loss is what gets transferred from pan to stovetop. (Fun fact: when I want to sear stuff for long enough that my induction burner would get too hot and shut off, I just introduce a thermal gap by setting the pan on top of a pair of chopsticks. Gets a few more minutes of full heat.)I used to swear by gas, but I’m an induction convert. Yes, gas retains some advantages, but induction heats faster, doesn’t heat the room nearly as much, and is far, far, far easier to clean.And induction is so efficient that a simple plug-in induction hot plate (the kind that use around 1800W and plug into an ordinary 120V/15A or 230V/10A outlet) outperforms many a “real” stove.But you are absolutely correct that the choice of cookware is essential. Even some cookware advertised as induction-compatible isn’t that great on it. (Luckily, that’s rare, and almost all the so-labeled cookware I’ve bought has been excellent. IKEA excels in this.) Cast iron, one of my favorites, works superbly on induction.

author: John B
author_rank: Frequent Contributor
timestamp: January 21, 2022, 10:34:36 pm
content: How many watts is your induction stove? I'm currently working out a full house worth of services. I'm thinking of consolidating all main energy users (hot water, cooking, heating) into electrical. Not sure whether paying the extra connection fee of gas will be worth it, especially with gas prices going up here.I mean, electricity is going up too, but I can live without gas, can't live without electricity.

author: tooki
author_rank: Super Contributor
timestamp: January 22, 2022, 10:57:17 am
content: Believe it or not, it’s a cheap 2000W induction hot plate. The actual stove in my (rental) apartment is conventional glasstop electric, which is fine (actually it’s a fairly decent one), but 99% of the time the stove is off and the induction hot plate is set on top of the stovetop and used instead. As alluded to above, its limiting factor isn’t actually power, but cooling: if I want to, say, sear tuna steaks for 4 people (2 fit in the pan at once), it will get too hot and turn off before I can get to the last 2. Proper induction stoves don’t seem to have that limitation. I’m sure they have thermal cutouts, but at much higher temperatures.Full induction stovetops typically have various size burners of various wattages, (going by memory here) perhaps 1400W for a smaller burner up to 2500W for an extra-large burner. Many have total cooktop wattage smaller than the sum of the burners, meaning that you can’t run all the burners at full power simultaneously. (Some, like my friend’s Samsung, also have power limits within pairs of burners.) Not really a problem in ordinary use, since one rarely needs to sear on maximum heat on all 4 burners at once, but worth checking into anyway.The only thing I would suggest is to avoid Samsung: my aforementioned friend in USA has one of those, and while it has no shortage of power, the pan detection on the burners isn’t impressive — it fails to reliably detect smaller pans the way I am used to on every other induction stove I’ve used (V-Zug, Electrolux, various cheap hot plates).

author: mcz
author_rank: Contributor
timestamp: January 22, 2022, 12:04:19 pm
content: Quote from: John B on January 21, 2022, 10:34:36 pmI have a Bosch 5-plate thingy and I believe the maximum rating for the entire unit is 9kW.i also did some measurements while heating water and a 3.3kW rated got me about 2.9kW (probably including all sorts of errors) of actual water heating power. 1L of water from 20C to 50C in about 45 seconds.