Backup Generator FAQ

When would I need a generator?

Generators are convenient should the power go out due to a storm or other natural event. They serve as a good backup system for heaters, refrigerators, freezers, pumps, and lights.

Two types of generators are available. The portable models are popular for those needing to power equipment remotely from hardwired electricity. Many are available for light-duty residential use, while other models can handle heavier residential and commercial use.

A second generator type is a permanent unit installed and attached to a home or business.

Generators typically run on propane, natural gas, or diesel, while portable generators typically run on gasoline.

What is a permanent unit?

Permanent units are automatic generators installed next to a home or business in a fixed location.

These units generally are directly wired into the main breaker panel and can operate the entire house in the event of an outage. In addition, they automatically turn themselves on when they sense a power fluctuation through an automatic transfer switch.

While these units are the most expensive to purchase, they are also the most convenient to operate.

How do I connect my portable generator safely?

There are two ways to connect a portable generator.

First, you can plug your appliances directly into the generator and run them as needed. Never connect your generator directly into your wall plugs, as it may cause an electrical fire inside your house.

Second, you can have the generator connected to your breaker panel, by a licensed electrician, through a manual transfer switch enabling you to throw the switch and have the necessary designated items continue to operate from the generator.

The main breaker on your panel does not qualify as a transfer switch under the National Safety Code. Using it in such a manner is illegal!

Never operate your generator from the inside of your home, as this could create toxic exhaust fumes, which could cause injury or death.

What size portable generator do I need?*

A generator’s size is indicated in watts. To decide what size generator to purchase, determine your power needs. Most electrical products have a tag indicating the amps and volts required to operate or their wattage. Amps multiplied by volts equals watts.

For light bulbs, hot plates, toasters and space heaters, figure the wattage by multiplying amps and volts. Do this for each item and add those figures for the total wattage needed. For example, the wattage of three light bulbs at 100 watts each totals 300 watts. Add a 1,000 watt coffee maker, and the total is 1,300 watts. Each additional item adds more wattage until you determine your total load in watts.

When a motor is required to start an appliance, it will require more wattage, such as refrigerators, freezers, water pumps, hairdryers, etc. They may need three times the rated power required to start up. To determine the appropriate wattage needed for one of these appliances, multiply amps x volts x 3.

Total all the wattage to calculate the size of the generator needed. The surge wattage is the watts shown on the side of generators (2,500W, 3,000W, 5,500W). Rated wattage is the amount of watts available for continuous running; surge wattage is the amount of watts available for a short time to start up an appliance with a motor. A generator’s rated wattage is less than the surge wattage. For instance, a 5,000W generator will deliver about 4,500 continuous watts.

Do I need any permits?

Yes. If you choose to install the transfer switch, the electrician will get the necessary permits for the job.

If you choose to operate a portable generator with items plugged into it, you do not need a permit.

However, please call CEC and let us know that you are running a generator for our line crew’s safety.

Can a generator hurt someone or something?

Yes. Emergency generators pose safety hazards.

Transfer switches are required because the generated electricity can flow through the meter base and into the distribution lines posing life-threatening risks to workers, neighbors, children or animals near a downed power line.

In addition, when the power comes back on, it flows back to your home and can seriously damage or destroy a generator without an approved safety switch.

Who can help me do this?

Your local electrician can provide you with information and assistance on generator installation and safety.

Before contacting an electrician, you may want to call CEC to find out the highest power demand reading for your home. Also, consider what other electrical equipment you may add to your home in the future, such as an electric vehicle. Or what equipment can help lower your demand, like a heat pump water heater. All these factors are a good starting point for your electrician in properly sizing your system.


*This sizing information is intended for estimating purposes only. Actual power requirements of high-demand appliances vary widely by brand, model and capacity. Please have an authorized dealer or qualified electrician analyze your specific needs before making a purchase decision.