(obscure) question about dual voltage in Canada

Most domestic properties have a 120/240V split phase supply:
https://i.stack.Upload the image directly to the thread.com/tRo7E.png

w0z said:

I was chatting to a non-technical person back over here for a visit but who now lives in Canada. He told me that the domestic voltage is 110v but some properties including his have a second feed of higher volts (unspecified but 200 and something Volts) for higher power domestic appliances.
Does anyone know how this is usually done? Is it simply a case of using the voltage across 2 phases of a 3 phase install?
He said he had no idea about this until he moved there and the only info I could glean was that it comes into the house at that voltage on a 'separate circuit' - he never installed any conversion equipment.
I tried a quick search but couldn't find anything.

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220V across 2 phases

That's the standard system in the U.S

Lighting and general purpose sockets for light loads are on 110v.

Air con and Washing machines or anything else with heaters in, is 220v

snowhead said:

That's the standard system in the U.S

Lighting and general purpose sockets for light loads are on 110v.

Air con and Washing machines or anything else with heaters in, is 220v

Click to expand...

Yes across 2 phases 220Volts covered by a DP OCPD.

i wouldn't call it 2 phases, rather a 240V single phase, centre tapped to split into 2 x 120V.the centre tap being the N.

freddo said:

Most domestic properties have a 120/240V split phase supply:
https://i.stack.Upload the image directly to the thread.com/tRo7E.png
View attachment 44281

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Thanks very much for the reply. I wonder what the the transformer rating is and how many properties each one feeds...

telectrix said:

i wouldn't call it 2 phases, rather a 240V single phase, centre tapped to split into 2 x 120V.the centre tap being the N.

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Agreed, it's known as split phase, the reason I couldn't find any info was because that was the term I should have searched for (the retrospectoscope is a wonderful instrument!)

that reminds me. i need a pee.

telectrix said:

that reminds me. i need a pee.

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that's split phase not split peas
and see what I mean, if you'd used the retrospectoscope you would have known you needed a pee before you needed a pee..

w0z said:

He told me that the domestic voltage is 110v .

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He was wrong. It is 120v.

Pete999 said:

220V across 2 phases

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No 240v.

snowhead said:

That's the standard system in the U.S

Lighting and general purpose sockets for light loads are on 110v.

Air con and Washing machines or anything else with heaters in, is 220v

Click to expand...

Why do so many people think it is 110/220v?

It is 120/240v plus or minus 5%. 110v is well outside that range.

snowhead said:

That's the standard system in the U.S

Lighting and general purpose sockets for light loads are on 110v.

Air con and Washing machines or anything else with heaters in, is 220v

Click to expand...

Why do so many people think it is 110/220? It is 120/240v plus or minus 5%. 110v is well outside that range.

Historically it was 110V, and we often call things in that voltage range '110V' simply to distinguish them from '240V' range, rather than to precisely state the voltage.

But I think the OP is talking about the 'high leg' aka 'wild leg'.

A normal US domestic supply is split phase, 120-0-120, i.e two hots 120V from neutral, 240V apart. Lights and normal sockets run from hot to neutral at 120V, heavier loads like tumble driers and air conditioning at 240V between the hots at 240V. On its own this system is single-phase, not two phases out of three, and may be supplied from a single-phase substation transformer. But you can make a 3-phase 240V delta supply out of it, by adding one more wire that is 208V from neutral, at 60° phase angle.

The high leg can be supplied from a separate single-phase transformer, making an open-delta edge-grounded supply, in which all single-phase load is on the 120/240, and only 3-phase loads use the (lower capacity) high leg. Or, if there is a lot of 3-phase load, a conventional closed-delta supply using a 3-phase transformer can be provided. The high leg is colour coded orange. Funny stories are told of situations where this gets connected to single-phase loads in place of one of the two hots that are 120V from neutral.

The domestic / light commercial customer who wants to run a 3-phase lathe in his garage, gets the high leg in addition to his existing 120-0-120, and presto he's got 3-phase.

The system cannot supply a 240V star load though, because the neutral is not at what would be the star point; it's halfway along one of the 240V windings. In any case the star voltage would be 139V.

See Google Image Result for http://forums.mikeholt.com/attachment.php?attachmentid=7057&d=1340325879 - https://www.google.com/imgres?imgurl=http://forums.mikeholt.com/attachment.php?attachmentid%3D7057%26d%3D1340325879&imgrefurl=http://forums.mikeholt.com/showthread.php?t%3D146083&h=400&w=590&tbnid=tDmX_K_26j1nDM:&q=high+leg+voltage&tbnh=152&tbnw=224&usg=AFrqEzdB5pM4uvELyZvH9v9c0eUEp-HTvw&vet=12ahUKEwjwq5numLjdAhVIsKQKHUYQC1kQ9QEwAHoECAcQBg..i&docid=XTMpRgxOYFoZYM&client=firefox-b-ab&sa=X&ved=2ahUKEwjwq5numLjdAhVIsKQKHUYQC1kQ9QEwAHoECAcQBg