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sbwright · Sep 26, 2008, 03:01 PM

So we have a 3-wire, 1-phase, 220v, 200a service in our home, in Canada if that helps.

My question is how many amps can be drawn from each of the 2 lines to neutral, my assumption is this:

L1 to Neutral max amp = 200 amps at 120 volts
L2 to Neutral max amp = 200 amps at 120 volts
L1 to L2 max amp = 200 amps at 220 volts

Is this correct?

Thanks for your help,
Brian

stanfortyman · Sep 26, 2008, 03:32 PM

You have a 120/240v, 200A service; capable of 200 amps @ 240v; or 48,000 watts.

sbwright · Sep 26, 2008, 03:40 PM

Originally Posted by stanfortyman

You have a 120/240v, 200A service; capable of 200 amps @ 240v; or 48,000 watts.

So my assumption is correct?

In particular the 120v sides, each can supply max of 200 amps?

Brian

stanfortyman · Sep 26, 2008, 04:05 PM

Originally Posted by sbwright

So my assumption is correct?

In particular the 120v sides, each can supply max of 200 amps?

Yes.

I will add that it is not technically correct nor customary to say this is 400A @ 120v.
200A @ 240v is the correct way to put it.

sbwright · Sep 26, 2008, 04:22 PM

Originally Posted by stanfortyman

Yes.

I will add that it is not technically correct nor customary to say this is 400A @ 120v.
200A @ 240v is the correct way to put it.

Thanks for the reply.

The reason I was asking, I am looking at installing some usage monitoring equipment which requires the installation of CT's on the main L1/L2 wires. The equipment's max amperage is advertised as 150 amps max. They are saying it is okay as our 200 amp service is really 100 amp/Line *2=200, which is not my understanding.

KISS · Sep 26, 2008, 05:28 PM

To answer your question in post #4. P=VI and 120*200*2 = 48,000 W. Bingo!

stanfortyman · Sep 26, 2008, 05:30 PM

Originally Posted by sbwright

on the main L1/L2 wires. The equipment's max amperage is advertised as 150 amps max. They are saying it is okay as our 200 amp service is really 100 amp/Line *2=200, which is not my understanding.

You can tell "them" that they are wrong.
You are correct on this.

Pretty scary that these folks are selling this stuff and they can't even get this basic concept right.

sbwright · Sep 26, 2008, 05:58 PM

I believe the answer to be correct

sbwright · Sep 26, 2008, 06:01 PM

Thanks for the responses stanfortyman and keepitsimple. Thought I was correct but it has been a long time.

Brian