Quick answer
Earth leakage that trips overnight is almost always the geyser. It cycles on while everyone is asleep, and if moisture has reached the element or the terminal box the leakage current appears at exactly that moment. The overnight pattern is the clue. Isolating the geyser breaker for one night confirms or eliminates it without any equipment at all.
Common causes
- Geyser element or gasket leaking to earth as it cycles overnight
- Damp wiring in the roof space, often after rain
- Outdoor or garden lighting with water ingress switching on at dusk
- Pool pump or irrigation controller running on a night timer
- Accumulated small leakage across several circuits crossing the trip threshold only under night load
What you can do now
- 1Switch the geyser breaker off overnight — if the earth leakage holds, the geyser is confirmed
- 2Note the time it trips and what is scheduled to run then, such as a pool pump or timer
- 3Check whether it correlates with rain, which points at outdoor circuits or the roof space
- 4Do not keep resetting it repeatedly; each reset re-energises whatever is faulty
- 5Keep a short written log of trip times — the pattern shortens the fault-finding considerably
When to call a professional
Book within days. Earth leakage trips are a shock-hazard warning, not a quirk of the board. Bring your log of trip times to the appointment. A registered electrician will insulation-test the circuits and the geyser element, and if the geyser is at fault the element and gasket should be replaced together — replacing one alone is why the trip often returns.
Typical cost in Johannesburg
Diagnostic R650 · Element + gasket R1,400–R2,000
Indicative ranges only. We provide written, itemised quotes before any work.
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