What is a Generator?

Generators are standby devices that can supply electricity to your home during power outages. During a power outage, it allows you to continue to operate essential appliances such as refrigerators, computers, heating, and cooling systems and lighting.

The process that generators employ involves converting mechanical energy into electric energy. This is the same process that is used, on a larger scale, to produce electricity for entire communities by your local utility provider. In essence, a spinning shaft powered by an engine is used to produce a magnetic field through a coil, which in turn produces an electromotive force.

Choosing a generator

Home generators can be either portable or stationary. They run on a variety of fuels including, gasoline, diesel, natural gas, propane, and oil. Generally, gasoline portable models are less expensive to purchase. However, they typically have shorter run times because of the need to refill the tank, if used constantly. And if you've lost power due to wide spread outages or severe weather conditions, gas pumps may not be operational. Natural gas, with its constantly available supply, tends to be the more reliable for stationary models.

The main differences between stationary and portable models are in their connection and activation. A portable unit has to be moved to your location, filled with fuel and then connected to the fuel line, manually started then connected to your load requirement. Portable units allow for easy storage when needed. A stationary unit can start immediately and is usually already wired to the home and the fuel source. When choosing which type of generator, consider how much space you have for the unit; a stationary unit may require a concrete pad.

Generators usually come in sizes that range from an output of 1 kilowatt (kW) to over 100 kW.

Choosing a fuel type

Your choice of fuel should be determined by the fuels available in your area. The more remote your location is, the bigger the concern for having available fuel will be. As mentioned earlier, gasoline, diesel, fuel oil and, to an extent, propane, have limited availability and delivery in extreme circumstances. Natural gas can also be limiting if you are not connected to their distribution system.

Wired Systems

A standby power backup device connects to the house wiring through a transfer switch. The transfer switch prevents ‘backfeeding’ into utility lines, which is dangerous and illegal. It also protects the device from damage caused by the utility company applying voltage to your house wiring while it is operating. These switches can either be automatic or manual and should be rated to carry the larger of the maximum load of the residence or the full output of the generator.


If your generator is intended to supply only a portion of your home's electrical load, make a list of the equipment you want to power in case of a power failure: appliances, lamps, furnace blower motor and the like. Compare the total wattage of the equipment to the total wattage output rating of the generator and do not exceed it.

Call your local Mister Sparky® electrician to install a stationary generator or perform a generator service. We'll ensure that all wiring and equipment comply with local, state and federal laws or codes, and adheres to the rules and regulations of your local utility. For more information, call Mister Sparky® at (800) 906-4577 today!