Backwiring: what you need to know

Trent Ernst, Editor


With the recent power outage, many people were wondering how to hook their generators to their houses so they could have power.

The first thing to know is it is illegal to connect a home portable or stationary generator directly to a house wiring system without the proper installation of a CSA-approved transfer switch. “Never plug a portable generator into a regular household electrical outlet. This can also cause back-feeding to the BC Hydro electrical grid, which is a serious electrical danger,” says the Hydro website.

BC Hydro’s Bob Gammer says this is for the safety of the people working on the lines. “We have crews out working in a neighbourhood. They know the line is de-energized, so they’re doing what they need to do. Suddenly, someone fires up a generator without the proper interface. The power starts flowing out of the house and into the area, and it can electrocute our workers,” says Gammer.

It can also cause problems for neighbours, who are also assuming the lines are de-energized.

According to BC Hydro, an electrical permit is required for the installation and the transfer switch. The generator must be inspected and approved by the local electrical inspector.

Local Tim Croston says, “Do the calculations on the equipment you want to run and ensure the generator is big enough to run what you want.” He says he knows a number of people who ran their furnace motors on generators. “They said ‘it ran a little slower but it worked.’ That’s a good way to burn out the motor,” says Croston. “I guarantee some miles were taken off a few furnace motors around town.”

If you don’t know what you’re doing, he says, “don’t be scared to ask for assistance.”

There are a couple different options for wiring a generator into your house, says Cliff from Erickson’s Electric in Dawson Creek. “You can do a whole house transfer, where your whole house is on the system, or install a genset panel, which is where you take four or five circuits off your panel, and onto a generator panel, where you can run those things from both the main panel.”

Of the two options, the latter is the least expensive, he says. “Once you’ve hired someone to do that, you’re looking at between $600 and $1,000.

For a whole house transfer, the switch itself is from $600–800, and by the time you hire someone to install it, you’re looking at a total of $1,500 to $2,000.”

And then, of course, there is the cost of the generator. Cliff says, in order to run the fridge, the freezer and the furnace, most houses need at least a 3500 watt generator, which start at about $500 and go up from there.

While it is a little more work to unplug your fridge and freezer and other appliances from the wall and into an extension cord, it is the most practical when there is an average of one power outage a year.

For more information on the correct way to connect your generator and to obtain a permit, please call your electrical contractor or the electrical inspector in your area.

Home generators can be useful during a power outage but they can also be very dangerous if they are not used properly. Always follow all manufacturers’ instructions and contact a qualified electrician or electrical inspector if you have questions.

Here are some other tips for proper use of generators during power outages:

Plug appliances directly into the generator or use a properly sized CSA-approved 3-pronged extension cord in good condition.

Use a Ground Fault Circuit Interrupter (GFCI) portable extension cord if using the portable generator to power electrical tools for outdoor use.

Keep the generator dry and protected from rain and snow.

Carbon monoxide (CO) is a colourless, odourless gas in the engine exhaust. You may not smell the exhaust but could still be exposed to CO. Never use a portable generator indoors, including inside a garage or other enclosed or partially enclosed area, and only operate them at a location where the exhaust cannot enter into your home or other buildings through doors or windows.