Is there 100 amps per leg on a single phase residential service

[scrapper329]

Is there 100 amps per leg on a single phase residential service or is it 100 amps total? I've been given 2 different answers by Com Ed in Chicago. Im wondering so when customers ask me I can answer correctly.

 

[charlie b]

I hate to do this to you, but it is both. But you are talking about apples and oranges here. 100 amps on one leg, added to 100 amps on the other leg, give you a total of 100 amps. The confusing part is that "amps" is not the same as "amps." Or more properly, one of the legs should be called "100 amps at a phase angle of 0 degrees," and the other leg should be called "100 amps at a phase angle of 180 degrees." When you add those two things together, you still end up with 100 amps.

 

[roger]

If it's a 100 amp service it's a 100 amps per leg, if it's a 200 amp service it's 200 amps per leg.

(Edit) or what Charlie said

Roger

 

[Smart $]

Is there 100 amps per leg on a single phase residential service or is it 100 amps total?

To state it a bit differently, it's 100 amps @ 240 Volts (Line1 to Line2). That's 24,000 Volt-Amperes (VA). When utilized at 120 Volts, you still have 24,000 VA available... but as 12,000 VA for loads Line1 to Neutral and 12,000 VA loads Line2 to Neutral. That would be, coinciding with charlie's response, 100A@0? and 100A@180? available for 120V loads.

 

[nukesparky]

Addition

Addition

That's right, these are not added as an "Algebraic" sum, but are added "Vectorally". So, the total is 100A.......:smile: