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Bingo.... That makes sense. So when I have a 200A mains breaker, I should only be subtracting the 30A from it, not the 60A. even though there are 2 30A breakers. Counterintuitive, but it makes sense.


Yup. Where it gets somewhat funny, requiring the more detailed explanations above, is when you add a breaker for a 120VAC circuit.

Those generally only count for "half" against the main panel's 220VAC capacity of 200A.

EDIT: Or rather, each pair of 15A (or 20A or whatever) 120VAC circuits counts as a single unit against the panel capacity. So two 15A 120VAC circuits normally present only a 15A max load on the main panel, assuming one of them is on one leg of the 220VAC, and the second is on the other leg of the 220VAC (which is how "paired/ganged" breakers are normally installed).

-ml


Edited by mlord (13/03/2007 15:27)