Power outages can leave a home without power for lighting, cooking, refrigeration and pumping water. Portable generators can be bought to provide substitute power. However, the generator must be properly sized to start the appliances and equipment you want to run.
What To Do
|Motor, hp||To start||To run|
determine how many appliances you want to run at the same
time and add or total the wattage. The size of the generator
you use must be such that it will start and run the necessary
appliances. If you get a generator that is too small to run
refrigerators and freezers, they will try to start, but the
voltage will drop and their motors will overheat and burn
out. If you cannot find the wattage, an estimate can be made
from the following table:
|Essential home equipment||
|Optional home equipment||
Electric skillet |
Central air conditioner
Ventilator fans |
Bulk milk cooler
For example, if you want a generator to run a refrigerator and a freezer, the wattage (table 2) of the refrigerator would be 800 and the freezer would be 1,000. To select the correct size generator, you decide if both refrigerator and freezer are to start at the same time. If so, you would need (1,800 X 4) 7,200 watts. You would select the nearest larger wattage generator. If you can be certain both appliances will not start at the same time, you would only need 4,800 watts (to run the refrigerator while starting the freezer).
Put the switch in a water-tight box and properly ground it, the central meter pole is a common location. Install the switch between the watt hour meter and the service disconnect (main fuse box). Note that the white (neutral) conductor is usually not switched, but some power suppliers require it be switched also. When the handle is up, the utility black and red conductors are connected to the load black and red conductors, respectively. In the down position, the load conductors are disconnected from the utility conductors and connected to the black and red conductors from the generators.
Publication #: 490-303
Based on information developed by Clemson Cooperative Extension following Hurricane Hugo. Revised for Virginia audiences by Virginia Cooperative Extension.
For more information, contact your local office of Virginia Cooperative Extension.
Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More