10kw heater with a 60 amp breaker on board. I have been told 8 gauge but I know that 8 gauge does not handle 60 amps. but I can get away with the 60 because we can rate the OCPD at 125% which brings it up to around 52.7 amps the next highest breaker is 60 amps does this sound right. the reason I ask is I have the ac man telling me he will fail inspection for the wire but I have done this before and I have been told b y inspectors that this is okay does this sound right thanks Ryan
What is the voltage? Let me presume it is 240 volts, single phase. 10,000 watts divided by 240 is 41.6 amps. This is a "continuous load" so the wires must have an ampacity of 125% of 41.6 amps, which is 52 amps. I don't have my book handy, so I don't know if a #8 will suffice. I will say that you must have a wire with an ampacity of at least 52. You can use a 60 amp breaker on such a wire, since it is the next higher rated overcurrent device.
Welcome to the forum.
Charles E. Beck, P.E., Seattle
Comments based on 2008 NEC unless otherwise noted.
What type wiring method will be used, NM or conduit? If NM I would feel comfortable with #6 @ 55amp, on 60amp breaker. Table 310.16 60deg due to 334.80 Ampacity requirement.
Last edited by 1793; 04-30-08 at 10:22 AM.
Norb
My Boss is a Tyrant and my Employee is an Idiot.
I use #6 Cu NM for 10kw/240v, also. If it were 208v, you could get away with #8, but with a 50a breaker.
Master ElectricianCode references based on 2005 NECLarry B. Fine
Electrical Contractor
Richmond, VA
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