How Emergency Power Systems Work

Hooking the Power into Your House

There are two ways for you to get power from the generator into your house:
  • You can run extension cords from the generator to specific appliances.
  • You can have an electrician wire the generator into your home's circuit panel so that you can switch the entire house over to the generator.
The first option is incredibly easy. If all you need to power is a refrigerator, a TV and a microwave, then this is a good way to go. If you need to power your furnace blower, a well pump and other large power consumers, then buying a 240-volt generator and having an electrician wire it into your circuit panel is the way to go.

To switch over to generator power:

  1. I ground the generator.
  2. I start the generator and let it stabilize for five minutes.
  3. I hook the generator up to the circuit panel.
  4. I flip the generator's circuit breaker. (The electrician will install an interlock system so that the panel's main breaker automatically cuts off when the generator's breaker turns on. This prevents the generator's power from travelling outside your home. See Installing a Backup Generator for details on the wiring.)
At that point, everything in the house has power. The challenge then is to make sure that multiple appliances do not compete with each other for available power. To stagger the load, all of the big power consumers (refrigerator, water pump, microwave) have their circuit breakers marked on the panel and I can turn them on and off from there.

Three points from the previous discussion are especially important:

  1. Have an electrician wire the generator in for you. It will cost $200 to $400 for a simple system.
  2. Be sure to ground your generator as described in the owner's manual. You can connect the generator's chassis ground to your home's grounding rod, or buy an 8-foot grounding rod at the hardware store for $12 and install it.
  3. Be sure to cut your house off from the power grid before starting your generator. If you don't, you risk electrocuting people working on the lines. In addition, your generator will be trying to power the entire neighborhood, and it obviously cannot do that. By having the electrician install a positive interlock system, the house's main breaker automatically cuts off when the generator's breaker turns on.

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