Service Entrance conductor size

[gent]

Main breaker is 200 amps but service entrance conductors are #2 copper. Electrician says this is fine because his calculated load is 125 amps.
He also installed these in a drywall cavity with no conduit or protection except "it's behind the sheetrock."
Any comments please?

 

[eprice]

Re: Service Entrance conductor size

I believe the 200 amp main breaker with #2 copper service entrance conductors is a violation of 230.90(A).

 

[charlie b]

Re: Service Entrance conductor size

I agree with eprice. First of all, if the calculated load is 125 amps, why is the electrician installing conductors rated only for 115 amps? Secondly, suppose one of the loads develops a problem. I don?t mean a short circuit, since that would trip the breaker. Suppose the load leaks current to ground, so that the total current on the circuit (i.e., load current plus leakage current) is 190 amps. The breaker (whose one and only one function is to protect the cable) will not trip (i.e., it will not protect the cable), and the current could cause the cable to overheat. Finally, since there is no conduit to separate the conductor?s insulation from the wall, there is a possibility that an overheated cable might set the wall on fire. I suggest that you discuss this installation with a different qualified electrician who would be more familiar than I with your local codes and with your local means and methods.

[ April 30, 2003, 02:49 PM: Message edited by: charlie b ]