Most homes in Ontario receive power on two 120-volt legs that combine to supply 240-volt appliances. When exactly half your house goes dead — or worse, when lights dim and brighten on their own — one of those legs or the neutral between them has failed. This is one of the few residential electrical problems we treat as a same-hour emergency.
How to tell what failed
Step outside. If neighbours have flickering or partial power too, or a storm just rolled through, the fault is likely the utility's overhead service connection — call Toronto Hydro, Alectra, or your local utility, and the repair costs you nothing. If neighbours are normal, the fault is on your side: a corroded connection at the meter base, a failing main breaker, or a loose lug inside the panel.
Inside, the symptoms tell you more. A clean half-house outage — some rooms dead, others normal, 240V appliances like the dryer running weakly or not at all — is a lost leg. Lights that surge brighter in one room while dimming in another mean a lost or loose neutral, which is the dangerous one: voltage stops dividing evenly and sensitive electronics can be destroyed in minutes. Unplug computers, TVs, and appliances now, not later.
Why this can't wait overnight
A failing connection at the meter or main breaker is failing because it's arcing — generating heat exactly where the most current in your home flows. These faults don't heal; they escalate, and panel fires disproportionately start at exactly these points. The repair itself is usually straightforward for a licensed electrician — re-terminating a connection, replacing a main breaker, or coordinating with the utility on a meter-base repair — and a same-day call is dramatically cheaper than the alternative.
The repair and prevention
We carry main breakers and meter-base components on the truck and resolve most half-power calls in a single visit; call 416-837-4038 any hour. If your panel is original to a 1960s–80s home, this failure is often the panel telling you it's done — corroded bus bars and tired breakers fail together, and a panel upgrade resets the clock entirely. A whole-home surge protector is also worth adding at repair time, because voltage events like a lost neutral are exactly what it protects against. For homes that have had one of these scares, our electrical inspection checks every high-current connection with a thermal camera so the next weak point is found before it fails.