Breakers V. subpanel...

[mrcaptainbob]

Why is there a limit on the number of breakers in a main panel? If each breaker would be replaced with a 'piggyback' (and probably add up to more than the panel's rated cap.), what does that tax in the panel? Would adding a subpanel possibly add more than the ability of the service wire capacity?

[Snoonyb]

The answer is,"add up to more than the panel's rated cap." IE. melted buss bars.

[HayZee518]

The manufacturer and the NFPA determines the number of full inch spaces a panel can hold safely. The standard is no more than 40 full one inch spaces. IF the panel could take 40 twin breakers that would mean 80 - 20 amp or 80 - 30 amp single pole breakers. When ya think of it, it is kinda scary. Even 40 standard breakers add up to 800 amp -- ON A 200 AMP BUS??
Did you ever put an amprobe on a fully loaded 200 amp bus with all circuits and devices operating? I have seen no more than 187 amps at any one given time in one certain house. This was obtained by adding the seperate loads on each cable of a 200 amp breaker.

[mrcaptainbob]

I see. It's hard to equate, what seems like a fairly substantial piece of metal, with that foil-like metal strap in the old plug fuses. Just doesn't seem like anything in a house would be able to melt that. It all adds up, though. Thanks for explaining it.

[HayZee518]

It makes ya think however - code states a 4/0 cable for a 200 amp service while the power company feeds the house with 1/0 BUT this is because the overhead is in free air -- so the cable size can be reduced and carry a lot more amps.