I live in a historic district that utilizes an ancient power ditribution system. As a result we are faced with MULTIPLE poweroutages every year. I am going to be buying a "Whole House" generator. I however, have no idea of the correct size. Rather than deal with a salesman who may provide me with information that suits his agenda (and pocketbook) rather than mine.

How do I correctly determine the load of all the circuits in my house?
We have a 100 amp electrical box with 4-30 amp , 5-15 amp, and 6-20 amp electrical breakers.
After pricing NG by the cubic foot and seeing what some models will consume a NG/LP model isn't feasible. NG here is just at $1 ft3 and these things use upwards of 150-200 ft3 per hour. No way. Looks like a gas powered manual type gen that will power only critical circuits of the house. Any other ideas?

MANPIG has the answer. You will also need a transfer switch as well to safely switch from the Line Voltage to the generator so only one Electrical source goes through your 100 Amp Load Center at a time.
Math formula for the size is:
P (Power) = E (Voltage) times I (Current)
So 240 Volts (120 + 120) time 100 Amps = 24,000 Watts
That's 24 Kw Max capability of your home.
A 25 or 30 Kw generator will do just fine and have a licensed electrician do the job (permits, inspections will be needed too!
Good Luck ! ! !

Filed under: Whole House Generator

Like this post? Subscribe to my RSS feed and get loads more!