Why does my breaker trip when it rains?

A breaker that trips when it rains almost always points to moisture getting into your electrical system somewhere — and this is a serious safety issue that needs prompt attention.

Water and electricity are a dangerous combination. When moisture infiltrates wiring, outlets, fixtures, or your panel, it creates a path for current to flow where it shouldn't. This triggers your breaker (which is doing its job correctly), but the underlying cause — water intrusion — can lead to arcing, corrosion, and electrical fires if left unaddressed.

The most common culprits are outdoor outlets, exterior light fixtures, or underground wiring that has developed a breach in its weatherproofing. Even a small crack in an outdoor junction box cover or a degraded conduit seal can let rainwater in. If the tripping circuit serves your garage, exterior lights, or any outdoor receptacles, start there. Similarly, if you have a detached garage or shed fed by underground wiring, a compromised conduit is a frequent offender — especially after Ottawa's freeze-thaw cycles, which are brutal on buried conduit and connections.

Another possibility is moisture entering through your home's envelope — around windows, soffits, or roof penetrations — and tracking down to a junction box or light fixture inside. Pot lights on upper floors are a surprisingly common entry point when there's a roof or flashing issue. You might also have a compromised weatherhead (where Hydro Ottawa's service line enters your home), which can allow water to run down into your panel itself. That scenario is particularly urgent.

From an Ontario code standpoint, all outdoor receptacles are required to have GFCI protection and weatherproof covers rated for "in-use" conditions (meaning they protect the outlet even with a plug inserted). If your outdoor outlets are older and don't have bubble-style covers, that's a likely entry point and a code deficiency worth correcting.

Do not ignore this or keep resetting the breaker. Water intrusion into electrical systems causes corrosion that worsens over time, and arcing inside a wall or junction box can start a fire with no visible warning. This isn't a "monitor it and see" situation.

A licensed electrician will use a process of elimination — checking outdoor boxes, tracing the circuit, inspecting conduit entry points, and looking for signs of moisture damage or corrosion — to find the source. In some cases, a thermal imaging inspection can reveal moisture pathways that aren't visible to the naked eye.

If you notice a burning smell, see any discoloration around outlets or fixtures, or the breaker trips immediately when it rains heavily, treat it as an emergency. Shut off the affected circuit and call right away.

For a proper diagnosis, Electrical Ottawa offers inspections for exactly this kind of issue. It's worth getting it looked at before Ottawa's fall rain season picks up. You can also reach ESA at 1-877-372-7233 if you have questions about permit requirements for any repairs that come out of the inspection.