Short answer: If your power trips when it rains, water is almost certainly getting into something electrical, most often an outdoor light, power point, junction box, pool or garden equipment, or a damaged underground cable. The safety switch is detecting current leaking to earth and doing its job. Leave the affected circuit off if you can identify it, don’t keep resetting, and have an electrician track down the leak with an insulation tester, ideally while things are still damp.
It’s a pattern many Inner West households know: a storm rolls through, the safety switch trips, and the power stays off until things dry out. It’s tempting to wait it out every time. But tripping in wet weather means there’s a real fault, and it’ll usually get worse. Here’s how to deal with it.
If you see sparking, smoke, or water near your switchboard or meter box, stay clear and call an electrician. If power lines are down, keep well away and call Ausgrid on 13 13 88, as Ausgrid’s emergency page advises.
Why rain trips the safety switch
A safety switch (RCD) compares current flowing out on the active wire with current coming back on the neutral. If some current leaks to earth, for example through water in a fitting, the RCD trips. The NSW Government notes safety switches cut power quickly to help prevent electric shock. So the switch is doing its job. The problem is wherever the water is getting in.
The usual suspects
| Where | Why it fails |
|---|---|
| Outdoor lights | Perished seals, cracked lenses, fittings not rated for exposure |
| Outdoor power points | Missing or broken weatherproof covers, poor mounting |
| Garden and in-ground lights | Water in junction boxes or connections |
| Underground cables | Old or damaged cable, often to a shed, garage or back gate light |
| Pool and spa equipment | Moisture in pumps, chlorinators or outlets |
| Hot water systems outdoors | Water entering the terminal cover |
| Air conditioner isolators | Weather-exposed isolators that let water in |
| Eaves and roof cavities | Leaking roofs dripping onto cables, fittings or downlights |
| Meter box | Water entering an old or damaged enclosure |
Narrowing it down
Step 1: which circuit?
At the switchboard, check which safety switch tripped. Then switch off all the circuit breakers under it, reset the safety switch, and turn breakers back on one at a time. The one that trips it is the circuit with the fault. Leave that one off.
Step 2: what’s on that circuit?
Think about what on that circuit is outdoors or near water: lights, power points, a shed or a pool pump. If you can, unplug outdoor equipment.
Step 3: note the pattern
- Does it trip only in heavy rain, or after you water the garden?
- Does it trip during rain, or hours later?
- Did it start after recent work, such as landscaping or roofing?
These clues help your electrician find the fault faster.
How electricians find it
We use an insulation resistance tester to test each circuit and section of cable. Faults that only appear when wet are easier to find while things are still damp, so call while the problem is happening if you can. Once found, the fix might be:
- replacing an outdoor light or power point with a properly rated one
- resealing or replacing a junction box
- replacing a damaged underground cable
- moving equipment out of the weather
Prevention
- Use outdoor fittings with a suitable IP rating for their location
- Keep weatherproof covers closed on outdoor outlets
- Don’t leave extension leads or power boards outdoors
- Get damaged fittings replaced promptly
- Plan underground cabling properly; see power to a shed or garage
Our outdoor and garden lighting guide covers choosing weatherproof fittings, and pool and spa electrical requirements covers pool equipment.
Power trips every time it rains? We find wet-weather faults with proper testing, not guesswork. See our fault finding service or call 0421 772 661, ideally while it’s still wet.
We track down rain-related trips in Marrickville, Leichhardt, Ashfield and Lilyfield.
Frequently asked questions
Why does my power trip when it rains?
Water is getting into an electrical fitting or cable, causing current to leak to earth. The safety switch detects it and cuts power.
Is it safe to keep resetting the safety switch after rain?
It’s better not to. Find the faulty circuit, leave it off and get it checked. Repeated tripping means there’s a real fault.
Can a leaking roof cause power to trip?
Yes. Water dripping onto cables, fittings or downlights in the roof space can trip the safety switch.
When should I call an electrician about rain trips?
As soon as you can, ideally while things are still wet, because the fault is easier to find then.