View Full Version : 70 amp circuit and 20Kw generator

Richard and Rhonda
11-14-2008, 02:08 AM
Michael and Tom have been after me for some time to look at my fuse box. The math doesn't work to have a 20Kw generator and a 50 amp main breaker. 50 amps x 2 legs x 120 Volts equals 12 kw. So I finally remembered to look today and voila the main is a whopping 70 amp breaker. 70(2)120 = 17kw Still don't know about the excess 3 kw.

11-14-2008, 03:11 AM
btw, mine has a 60amp breaker and so does michaels i believe.

i also believe the generator cooling blower motor is consuming power before the panel. mine is a 1hp motor is 746 watts continuous under perfect conditions and with normal loss could be 1000watts ish and of course the LRA at startup can be 2-3x the continuous wattage. so, there is 1000 watts or so taken off the top of the generator to power the blower.

thanks for looking, but it still doesnt solve where the rest of your generator current could be used.....


11-14-2008, 03:41 AM
With the 70 amp mains, I am more comfortable with a 18-20 KW generator. I know that it is always better to have some excess capacity than to run right on the edge for issues such as wiring losses, blower usage, etc.

Tom is correct, I do also have 60 amp mains with my 12.5 KW generator.