I have a two family home with a 200 amp service drop and two 200 amp panels this seems a little off to me because cant the two 200 amp panels draw more than the single 4/0 service drop can supply. My second question is does each panel need a #4 run for the cold water ground or can I run one and jump between the panels
Do you have a single 200 amp disconnect at the meter or 2 200 amp disco's. If you have 1 disco with 2 200 amp panels, the single 4/0 is OK, although unusual. If you have 2 200 amp disco's then you MAY have a problem. You might want an electrician to actually look at it rather than diagnose by computer.
#41401 - 08/25/0409:06 PMRe: two family with two 200 amp panels (overload?)
I'd say the 200 amp drop seems undersized...but only if the load of the 2-family is more than the service entrance cable can handle.As for the grounding electrode conductor,I just would run one #4 to the cold water pipe and just tap the #4 above the 1st panel with a burndie and drop into the 2nd panel...don't forget to supplement with 2 ground rods!
#41402 - 08/25/0409:11 PMRe: two family with two 200 amp panels (overload?)
Roger...if the cold water pipe is for connection of the GEC then it must be sized according to table 250.66 which would probally be a #4 copper for a 200 amp SE cable and if it were just a metal water pipe bond then it also must be sized according to table 250.66 except as permitted in 250.104(A)(2) and (A)(3) 250.104(B) is for "other metal piping"
#41407 - 08/25/0409:59 PMRe: two family with two 200 amp panels (overload?)
There are two 200 amp main breaker panels with no disconnect outside. It is a combo meter pan. The lugs in the center definately accept the 4/0 then buss bars feed the meters. It looks like they are suppose to be 100 amp meters. Because the 4/0 SUE cable that feeds the panel from the meter did not fit under the lugs of the meter so someone made the 4/0 fit into the smaller lug by cutting off some of the strands. The lugs on the meters are one piece.
Thank you for the quick response I will read the arctice numbers that were mentioned