On May 7, 4:24�pm, "John Grabowski" wrote:
"Big Giant Head" wrote in messagenews:Xns992974D19E174bigxgiantxheadSPAMBL@2 07.217.125.201...

On branch circuits the size of the wire and type of circuit determines the
breaker size but what determines the size of the main or combination of
mains? *Can it be as large as the panel is rated for or must it match the
size of the utility's drop?

We have an old panel with two mains, one is a double 50A feeding the rest
of the panel. *The other is a double 30A feeding the dryer outlet
directly.
The town now mandates 100A and I think homes get inspected when sold.
Rather than replace the whole panel I could replace main #1 with a double
70A (if available) OR maybe better would be to replace main #2 with a
double 50A (or higher) and have it feed a small subpanel in which I would
put a double 30A for the dryer and maybe throw in a few others as well.
That's within the rating of the main panel but not sure about the utility
drop.

It sounds as though you have an old split bus panel. *No main was needed for
the entire panel, but only for the lower section due to some archaic six
circuit code exception which saved the original installer the cost of a main
breaker.

It's possible that your service already is 100 amp. *You can determine this
by the wire size of the service. *Assuming other things are in good
condition you may be able to get away with just replacing the panel. *The
grounding electrode system will need to be updated as well.

Do not replace the existing breakers with a larger size. *Most likely the
wire will not be rated for the larger size.

what condition is the existing drop and amp capacity of meter can?