Half My House Has No Power: Causes and What to Do

It's a confusing situation: some of your lights and outlets work fine, but others are completely dead. The whole house didn't lose power, so it isn't a neighbourhood outage. So what's going on?

Most North American homes, including those across the GTA, are fed by a 240-volt split-phase service. Two 120-volt "legs" come into your panel, and your circuits are divided between them. When one leg loses power, roughly half the house goes dark while the other half keeps running. Understanding that setup explains almost every "half my house has no power" case, and some of those causes are genuinely dangerous.

The Common Causes, From Simple to Serious

1. A tripped breaker (the easy one)

If only a room or two is affected, the simplest explanation is a single tripped breaker. Open your panel and look for a breaker that's in the middle position or sitting slightly off from the others.

To reset it, push it firmly all the way to OFF, then back to ON. If it holds, you're done. If it trips again immediately, stop and treat it as a fault that needs investigation rather than repeatedly resetting it.

2. A tripped GFCI you forgot about

Multiple dead outlets, often in a bathroom, kitchen, garage, or outdoors, can all trace back to a single tripped GFCI receptacle "upstream" of them. One GFCI can protect several other outlets. Find any GFCI outlets (the ones with TEST and RESET buttons), press RESET, and see if power returns to the dead outlets.

3. A utility-side problem

Sometimes the fault is on the utility's equipment, not yours. A failing connection at the transformer, the service drop, or the meter can knock out one of your two legs. If you've confirmed your breakers are fine and a large portion of the house is dead, the problem may be on the utility side. In the GTA that usually means contacting your local utility, such as Toronto Hydro or Alectra, depending on your area.

4. A loose or failing connection in your panel or service

Connections loosen over time from heat cycling and vibration. A loose neutral or a loose connection on one of the legs in your panel or main service can cut power to half the home. This needs a licensed electrician, because the panel is live even when individual breakers are off.

5. A lost (open) neutral, the dangerous one

This is the cause you most need to recognize. The neutral wire is the shared return path for your two 120-volt legs. When that neutral connection breaks or comes loose, somewhere between your panel and the utility, the voltage stops splitting evenly. Instead of a steady 120 volts on each side, one side can swing dangerously high while the other drops low.

The result is bizarre and destructive: lights flicker or pulse, dim on one side of the house while glowing too bright on the other, and electronics can be damaged or destroyed by overvoltage. A lost neutral is a recognized fire and equipment hazard and needs immediate professional attention.

Danger Signs: Stop and Treat It as Urgent

Call for help right away, rather than troubleshooting further, if you notice any of these:

• Lights flickering, pulsing, surging bright then dim, especially varying between different parts of the house. This is a classic lost-neutral signature.
• A burning smell, buzzing, crackling, or warmth coming from the panel, the meter, or any outlet.
• Scorch marks or discoloration on the panel, an outlet, or the meter base.
• Electronics behaving strangely or getting damaged: bulbs burning out fast, devices resetting, transformers buzzing.
• A breaker that trips instantly every time you reset it.

These point to overvoltage or a fault that can damage your home and appliances, and in some cases start a fire. This is not a wait-until-morning situation.

What You Can Safely Check Yourself

Limit yourself to no-tools, no-panel-disassembly steps:

1. Check whether neighbours have power. If the street is dark too, it's a utility outage and you just need to wait or report it.
2. Open the panel cover and look for a tripped breaker. Reset it once, fully OFF then ON. If it won't hold, leave it off.
3. Reset any tripped GFCI outlets.
4. Unplug sensitive electronics if you suspect a lost neutral and the lights are surging. Protecting them while you wait for an electrician can save expensive damage.

Do not remove the panel's inner cover, touch the main lugs, or poke around the meter. Those areas stay energized even with the main breaker off, and the available current there is lethal.

When to Call a Licensed Electrician

Call a pro if:

• Resetting breakers and GFCIs doesn't restore power.
• You see any of the danger signs above, especially flickering or surging lights.
• A large section of the home is dead and your breakers all look normal, which points to a leg or neutral problem in the panel or service.

If your utility confirms the supply to your home is fine, the fault is on your side of the meter and needs a licensed electrician to safely open the panel and find it.

Don't Let a Lost Neutral Become a Fire

Partial power loss ranges from a trivial tripped breaker to a serious lost-neutral fault that can wreck your electronics or start a fire. The flickering and surging signs in particular should never be ignored.

Our licensed and insured electricians serve the Greater Toronto Area and can safely diagnose whether your problem is a simple reset, a panel connection, or a service issue. Call (289) 799-3802. If your lights are flickering or surging, you smell burning, or half your home is dead, tell us when you call and ask about same-day and emergency availability, and we'll do everything we can to get to you fast.