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Partial power outage in the house: what to do
Some rooms dark, others lit, the stove no longer heating: what it means, the safe steps to take, and who to call first.
In short
This guide covers a partial power outage: part of the house has no power, the rest still does.
- Call us first at 438 542-7304, 24 hours a day: we find the cause and tell you whether Hydro-Québec needs to be notified.
- Half the house dark, with the stove or the dryer stopped, often means the 240 volts is missing.
- Switch off the main breaker if you can do it without risk, move away and call us.
- Hydro-Québec repairs its service drop; the mast, the meter base and the panel are yours and are repaired by a master electrician.
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What a partial power outage means
Power comes into your home on two conductors of 120 volts each. Together, they give the 240 volts that large appliances need.
Outlets and lights are spread over one or the other of those two conductors. If one of the two is lost along the way, part of the house goes dark and the rest stays lit.
The stove, the dryer, the water heater and the baseboard heaters use both at the same time: without one, they stop or heat poorly.
Hydro-Québec lists this situation among the known problems of 120/240-volt homes: no voltage at 240 volts, which can require a master electrician.
Another possible sign: lights dimmer than usual, or that vary. According to Ontario’s Electrical Safety Authority, dim, surging or flickering lights can be a sign of a loose connection, even in the electrical service, with a risk of electrical shock or fire.
It is not a partial outage if only one room, or only one outlet, is affected: it’s more likely a breaker or an outlet. Our guides Breaker keeps tripping: causes and what to do and Outlet not working: what to check cover it.
The safe steps, in order
- If the basement is flooded or the floor is wet near the panel, stay away from it: get out without touching the water, then call us.
- Otherwise, switch off the main breaker if you can do it without risk, move away and call us at 438 542-7304.
- Don’t keep resetting the main breaker: resetting doesn’t remove the cause.
- Turn off the appliances that were running when the outage started: stove, dryer, washer, dishwasher.
- When the power comes back, turn the heating back on gradually, one heater at a time.
In a flooded basement, Hydro-Québec allows switching off the main breaker only if everything is dry: the floor around the panel, your hands, your feet and your shoes, without touching any metal.
A burning smell, smoke or flames change the order: get out, go to your meeting point and dial 911.
At home or on the grid
A whole street without power is the grid. A half-lit house is less simple: the loss can be at your place or on Hydro-Québec’s service drop: call us, and we’ll tell you as soon as you call.
To sort it out in a few questions, use the tool on our page 24/7 emergency electrician: it asks whether the outage affects everything, one half or a single room.
Half the house without power?
We arrive in 90 minutes or less, day or night, anywhere in our service area.
Call 438 542-7304What we look for when we arrive
We look for the spot where one of the two conductors is lost: at the main breaker, in the service entrance or at the mast.
The boundary between your installation and Hydro-Québec’s is called the connection point: it is at the service bracket, the metal piece where the conductors coming from the pole are attached.
If the loss is before that point, on Hydro-Québec’s service drop, we tell you, and that is when Hydro-Québec is notified at 1 800 790-2424.
If it is after, at the bracket, the mast, the meter base or in the panel, it’s your installation, and repairing it is a master electrician’s job.
The meter, for its part, belongs to Hydro-Québec: we don’t touch it.
Why you shouldn’t wait
A partial outage is not just an inconvenience: the failing connection can heat up. That’s why we treat it as an emergency.
Ontario’s Electrical Safety Authority says so too: a loose connection in the electrical service can present a risk of electrical shock or become a fire hazard.
In winter, there is one more reason: baseboard heaters run on 240 volts. Without one of the two conductors, they only heat halfway, and the house cools down.
Don’t make up for it with extension cords run from the rooms that still have power. Québec.ca points out that an extension cord is a temporary solution and that a space heater plugs directly into an outlet, without an extension cord.
Who repairs what: your installation, the service entrance, the grid
Almost everything attached to your house belongs to you. The meter is the only visible exception.
| Part | Who owns it | Who repairs it |
|---|---|---|
| Line, pole and conductors up to the bracket | Hydro-Québec | Hydro-Québec |
| Service bracket and mast | You | Your master electrician |
| Meter base (the meter’s box) | You | Your master electrician |
| Meter | Hydro-Québec | Hydro-Québec |
| Panel and main breaker | You | Your master electrician |
Table taken from our guide Mast, meter base, meter: who pays for what in Québec, which covers each part according to Hydro-Québec’s standard.
In Québec, a Régie du bâtiment licence is required for any work on the electrical installation, even in your own home.
Our emergency service, anywhere in our service area, is described on our page 24/7 emergency electrician.
Frequently asked questions
Why does only half of my house have power?
Because one of the two 120-volt conductors supplying the house no longer gets through. The lights and outlets that depend on it go dark, and 240-volt appliances stop. The loss can be at the main breaker, in the service entrance or at the mast.
The lights are dim and the stove doesn’t work: what’s going on?
It’s the typical sign of a lost 240 volts: the stove uses both conductors, and dim lights can signal a loose connection. Switch off the main breaker if you can do it without risk, and call us.
Is it dangerous to live with a partial outage?
Yes: the connection at fault can heat up, and a loose connection in the electrical service can become a fire hazard. Don’t put up with it until morning: call us at 438 542-7304, 24 hours a day.
Can Hydro-Québec fix a partial power outage?
Only if the cause is on its service drop, before the bracket. Call us first: we find the cause, and if it is on the grid, we are the ones who tell you to notify Hydro-Québec. If it is at your place, it’s a master electrician’s job.
Half the house without power?
Call us first: we are at your home in 90 minutes or less, day or night.
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Sources
Consulted on November 5, 2026.