Generators and transfer switches: powering your house safely during an outage

Why never through an outlet

A double male-ended cable sends the generator’s power into the house wiring and, through the meter, into the utility’s network. Line workers repairing the line believe it’s dead. It’s also a fire and shock hazard in your home. No exceptions.

Temporary or permanent: two ways to do it

For a permanent installation, Hydro-Québec asks you to have the master electrician install a compliant transfer switch, declare the installation to Hydro-Québec and check that the system fully isolates the house from the grid during an outage.

The three devices

1. The panel interlock: a mechanical part that prevents the main breaker and the generator breaker from being on at the same time. Simple and economical, if your panel is compatible.
2. The manual transfer switch: a small panel next to yours, with the essential circuits. You switch each circuit over to the generator.
3. The automatic transfer switch: for a standby generator. The house restarts by itself, and goes back to the grid when power returns.

In all three cases, an outdoor power inlet receives the portable generator’s cable, outside, away from windows.

Without an installation: plug appliances in directly

If you don’t have a transfer switch, Hydro-Québec gives the steps:

• plug the appliances directly into the generator or battery;
• use heavy-duty extension cords, certified for outdoor use and rated for the current;
• never a male-to-male adapter, never a wall outlet, never a direct connection to the panel.

Undersized cords can overheat and cause a fire or a shock.

Always outside

Gasoline and gas generators produce carbon monoxide, an invisible, odourless gas. Hydro-Québec says to set them up outside, in an open, well-ventilated spot, away from doors, windows and air intakes, and never indoors, even in a garage with the door partly open: poisoning can be fatal within minutes. A carbon monoxide alarm in the house is one more good protection; see Smoke and carbon monoxide alarms.

Portable or standby

• Portable (gasoline or propane): less expensive, to take out and start yourself, to place outside, never in the garage.
• Standby (propane or natural gas): installed on a pad, starts by itself, regular maintenance, coordination with the gas supplier.

Choosing the essential circuits

Backup heat, well or sump pump, fridge and freezer, a few outlets, lighting, the modem. Motors (pumps, fridge, furnace) draw more when starting: we take that into account in choosing the generator. Central electric heating and a heat pump often exceed a portable unit.

Our What size generator do you need? tool adds up your appliances’ watts, starting included, based on Honda Canada’s wattage guide.

The outage procedure

1. Turn off the main breaker, or flip the transfer switch.
2. Connect the generator to the inlet, outside.
3. Start it, then turn on the generator breaker.
4. When power returns: the reverse. We walk through the procedure with you at handover.

During the outage itself, see also our outage instructions.

With LTE Électrique

We install the interlock, the manual or automatic transfer switch and the outdoor power inlet, and we choose the essential circuits with you based on your generator. The price is announced in advance, fixed or hourly depending on the project, and labour is guaranteed for 2 years. Send us a photo of the panel and the generator model: the estimate is free, within 24 hours.