Split phase wiring, just out of curiosity...

I was reading this thread and I have a question.

In the UK all domestic circuits are single phase 240V (nominally 220V but often higher), there may be multiple phases in the house but as we can plug in 3000 watts of load into each socket we don't need the additional capacity. Larger devices like showers and ovens get a dedicated radial, usually up to 50A.

What this means is that I have no experience of the split phase system used in the US. I realise you have 2 hot legs coming into the house with a centre tapped neutral for 120v and can connect across the legs to get 240V.
My question is, are both hot legs wired in black? So your Romex(?) has a bare earth wire, 2 black wires and a white neutral? Or does one of the legs run on the white and you don't have a neutral?
 
European 3 phase runs each hot leg in brown, black and grey, with neutral in blue and a bare earth. (Brown and blue are standard hot and neutral for single phase)

Also, what's the arrangment for GFCIs in split phase? In the UK, circuits are protected by RCDs (GFCIs) back at the consumer unit (breaker board?). It's incredibly rare to have indivdual sockets with a built in RCD. (We like to protect the house wiring as well as the appliance wiring)    

I'm not quite sure what you're looking for.

All house wiring in Canada/US is single phase. Three-phase is only used in industrial applications.

Typically, 220VAC is made available to the main breaker panel. This is a two wire supply, supplying 110 to neutral on each side. 220 is used for heavy current loads like electric dryers, electric stoves/ovens, and long-run wiring to things like submersible well pumps. Everything else is 110. Ground fault and arc fault circuit interrupters are 110, mostly found in outdoor, bathroom or bedroom applications. I think electrical code is now specifying full-circuit protection for some house areas, as opposed to individual outlets.

Edit: If I have spoken out of turn regarding US applications, please correct me. My understanding is that our systems are pretty much identical except for the inevitable local code variations.

I'm mostly interested in the colour coding.

In the other thread an oven was giving shocks, a potential reason given is that the neutral could be broken. Leaving aside the liklihood of that happening, would a 240V oven even have a neutral internally connected? And do 240V sockets for ovens have a neutral?

I'm not sure which thread you are referring to. All of the 220 wiring I have seen has a black and a red supply (110 + 110), plus a white neutral and a ground.

Also, this is a two breaker system. The breakers are ganged together, so that a fault in one trips the whole circuit.

Thanks Douglas, this was the thread I was looking at https://permies.com/t/153485/shocked-shocked-feels

Some are three prong just like the UK, black white and green/bare.  Some are four prong, black red white green, because the clock and controls run on 120.

I'm no electrician, but I think the coloring system is confusing. I have recently found that the colors are not always set in stone, also (maybe due to stuff going between countries more). "Phase" here refers to the timing of the sine wave, not the amplitude. Three phase power has the three phases spaced equidistant from one another. There are about thirty different 220v plugs I have seen, and whichever one you have is typically not the one you need, in my experience. Some are as small as a 110v plug and only have three prongs, some larger ones have four prongs, one being a dedicated ground. The three prong plugs use the common as the ground, similar to how a two-pronged grounded 110v plug does. I believe this convoluted system is the result of the evolution of electricity, and trying to keep old stuff working while introducing newer, safer technology.

We still have a little bit of the convolution left here.

The current plugs, BS1363, came in in the 50's but there are still the old round pin BS546 plugs and sockets. They are pretty much all gone from houses, althought the 15amp version is still a standard for live event lighting, it is dieing out due to dimmer packs being replaced with LED fixtures.

Oh and we do have a 2 pin shaver plug and sockets. These are the only type allowed in wet areas (bathrooms) and are only commonly found in hotels. These accept american plugs and then immediatly blow the transformer/fuse as they are only rated for 0.2amp and won't power hair straightners.

R Scott wrote:Some are three prong just like the UK, black white and green/bare.  Some are four prong, black red white green, because the clock and controls run on 120.

Why run the controls on 120V? If everything runs on 240v it can be freely exported and imported across most of the world. Probably not a permie way of thinking but it make no corporate sense to use 2 different power standards in one device.


The industrial standards here are europe wide with many options. You can have 16amp, 30amp, 63amp... , 110V, 220V, 415V... At least the voltages are colour coded, yellow plugs for 110V, blue for 220V and red for 415V.

You'll see I switch between 240V and 220V, that's because before harmonisation, the UK standard was based on 240V and Britain still uses that standard. 220V comes from europe but the permissable voltage range is wide enough that the british standard fits inside that range.

It's good fun looking at american equipment and having to remember that black is live. Pre-harmonisation, black was neutral and red live, this is still very common in domestic wiring.
 

Most of the countries that have higher voltage (220v) typically use 50Hz power where as NA uses 110v at 60Hz.  That difference in the cycle on alternating current will kill a lot of electrics - particularly things with electric motors but also a lot of lights.

Incandescents should be fine...

Honestly any control system that has a problem with that these days is a pretty sloppy design.