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What a circuit breaker does, and its types
What a breaker does, the four types you find in a panel, and the real difference with a fuse.
In short
A circuit breaker automatically cuts the power to a circuit when there’s an overload or an anomaly, then is reset by hand.
- Standard, main, GFCI or arc-fault: each one protects against something different.
- A fuse of the right size protects as well as a breaker; the danger is a fuse replaced with a bigger one.
- The main breaker cuts the whole house at once.
- Replacing one is electrical work: it’s for a licensed contractor, even in your own home.
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What a circuit breaker is for
Hydro-Québec sums it up this way: the breakers in your panel automatically cut the power during an overload or any anomaly.
Each breaker protects one circuit. When it trips, it protects that circuit’s wiring; once the cause is fixed, you reset it with one motion.
Fuse or breaker
Both do the same job. A fuse of the right size cuts the circuit on an overload exactly like a breaker, and even a little faster.
The difference is practical: a blown fuse is replaced, a breaker is reset. And that’s where the fuse becomes risky, when someone replaces it with a bigger size so it stops cutting out.
Your panel still has fuses? Our guide fuse box replacement explains what to do.
The main breaker
It’s the big breaker at the top of the main panel: it cuts the whole house. If you smell burning, feel heat or hear crackling, switch it off if you can do so safely, step away, then call STM-Électrique at 438 542-7304.
GFCI and arc-fault: two more protections
A GFCI cuts the power as soon as it detects a leak to ground. The Code requires it where electricity and water can meet, and outdoors: bathrooms, kitchen counters, garage, unfinished basement, around a pool or a spa. The details: GFCI outlet or breaker, what it protects and where you need it.
An arc-fault breaker cuts when it detects an electrical arc in the wiring or an appliance. Since the 2018 Code, it’s required on almost all 120 V outlets in a dwelling. The details: arc-fault breaker, where Québec’s Code requires it.
When it trips
Four causes come up: an overload, a short circuit, a ground fault or an arc. A ground fault even makes it trip again as soon as you reset it.
The right moves and when to call are in our guide breaker keeps tripping.
Replacing it, and who does it
Replacing a breaker is work on an electrical installation. According to the Régie du bâtiment, that work must always be done by a contractor who holds the appropriate licence, even in your own home.
When the problem isn’t a breaker but a panel that’s full or too small, the solution is elsewhere: a sub panel or a bigger panel, depending on the load calculation.
Frequently asked questions
What’s the difference between a fuse and a breaker?
Both cut the circuit on an overload. A fuse is replaced, a breaker is reset. The risk comes from a fuse replaced with a bigger one.
What is the main breaker?
The breaker that cuts the whole house, at the top of the main panel. Switch it off if you smell burning or feel heat, if you can do so safely.
Why does my breaker trip?
Overload, short circuit, ground fault or arc. If it trips as soon as you reset it, don’t force it: call.
Can I replace a breaker myself?
No. It’s work on an electrical installation, which the Régie du bâtiment reserves to a licensed contractor, even in your own home.
Where is a GFCI breaker required?
Where electricity and water can meet, and outdoors: bathroom, kitchen counter, garage, unfinished basement, pool or spa.
A breaker causing trouble?
We find the cause, and the price of the fix is in the written quote, free of charge.
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Sources
Consulted on November 5, 2026.