How can I determine what the correct size generator will be for my home?

Question

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?

Answer 1

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 ! ! !

Answer 2

Very few homes ever consume the full capacity of their electrical feed system. You will not need a generator capableof supplying 100A.

Few things to consider before you spend money. Do you want an automatic system or will a manual system suffice? Are you willing to do without items such as air conditioning, electric stove or electric clothes dryer during an outage?

I spent about $1100 total on a manual system a few years ago. It consists of a 5kW portable generator and 12 circuit transfer panel. During a power outage I have to manually pull the generator out of the garage, start the engine, plug into the panel and throw the switch. The generator powers my well pump, furnace, fridge, freezer, microwave and toaster ovens, lights, and a few other items. It is perfectly comfortable, even during winter, and we can get by without full power throughout the house. I consume roughly one tank of fuel per day, with the engine operating for about 14 hours.

You can retrofit a gasoline engine to operate with natural gas or propane. Follow proper storage techniques for gasoline, diesel, or other flammable liquids.

If a fully automated system is required I'd suggest getting something powered by propane or natural gas if they are delivered to your house. Otherwise diesel is a good option over gasoline. Get a few price quotations from reputable dealers, discuss with them your needs and requirements. They may have other ideas or suggestions which will make the system better for you.

Read through my home generator page for other information and ideas.
http://members.rennlist.org/warren/generator.html

Answer 3

The best way to determine the right size bike for you is to deal with a bike shop that is equipped to do a proper fitting for you and the type of riding you plan to do. There is no sense in being fitted for a road racing bike if you plan to ride in the woods. I suggest going to 3 shops, tell the staff in each place what you want to do with your bike, see if you can agree with them on your budget, then buy where you had the best experience. Different types and brands of bike fit differently. A 58 cm road bike in one brand might fit you, while in another brand you might need a larger or smaller size. Mountain and hybrid bikes are completely different from road bikes for fitting, and again, different brands size up in different ways. Your body proportions determine what size bike you need, not just your height.

Answer 4

This is where getting multiple bids comes in. If you see a big difference in prices, ask why. Since you will also need a splitter (to disconnect from power company while using it) ask about everything you need to buy besides the generator. A call to an electrician may give you the answers you need also.

Answer 5

Volts x amps =watts...............Justv remember,you probably wont be running everything at the same time.If you have 100 amp service,a 15k watt generator should be plenty,you can run about 50 amps off that...one bit of advice,get a propane or natural gas powered generator,you dont want to have to dump gas in it every 8hrs.

Answer 6

Easy. Ask your wife how she determines the correct size for undergarments.