Ok...in a residential 200A service, if you add up the breakers you can have well over 200A. I realize that not all the loads are on at the same time which is why the main doesn't trip...but how does one really KNOW if the service can handle all the ciriuts..and is this information found in the NEC??
Also...as far as subpanels go....what's stopping me from putting a 100A sub at the end of the house opposite the main panel? and then adding another 100A sub in the garage for a welder and other shop machines?
Clyde: Math 40 circuit panel....20 amp, 1 pole cb's 800 amps; divide by 2 hot legs (resi)= 400 amp max connected load. BUT, the 200 amp main would trip.
Load calcs are in the NEC
Theory is you can have an unlimited quantity of "sub-panels", the limitations are the OCP of the main, and the OCP of the feeders.
Overcurrent protection is not the load. Also figure in the demand factor. I tend to be suprised how little draw I find on a panel for a big place on a normal day.
Besides reading the NEC you might try books explaining the NEC. I like Illistrated ones because a picture is worth a lot of big words for me.
