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Generator Sizing

With the winter comes the problem of power outages. Most of the time these outages can be restored quickly without too much hassle.

Depending upon where your location is, the outage can become days instead of hours. This is the time when you will start looking for a generator. Generators can be purchased in numerous sizes and applications. Most of the simple generators are portable and usually are 5000 watts or less. These generators are great and are designed for temporary, quick available power, usually with the use of extension cords.

When it comes time to supply your whole house during extended power outages, these generators are undersized for this application. The 5000-watt generators are calculated with usage being only 110-volt receptacles. Now, if you plan to use just extension cords, then there should be no problems as long as you don’t exceed the 5000 watts. Your house panel requires 220-volt power. When you use a 5000-watt generator, you have raised the voltage, which reduces the wattage from 5000 watts to 2500 watts or a 20-amp/220-volt source. The minimum main house panel is 100 amp, and under normal operation the home probably uses 50% of this power. Now you can see that the simple generator is not large enough to supply needed temporary power.

Another problem that can exist is how to safely disconnect the house panel from the utility company so that power you are generating is not being back fed into the utility lines. This is where a licensed electrical contractor will be able to assist you in the proper sizing, application, and safe installation of your new generator.