An earth-leakage switch that keeps tripping is annoying, but it mostly means your protection is doing its job. Here is what causes it and what you can safely check.
What does an RCD do?
The aardlekschakelaar watches for current leaking away — through moisture or a faulty appliance. The moment it does, it cuts power in milliseconds to prevent electrocution and fire. A switch that trips is, at heart, good news.
Common causes
A faulty or damp appliance (washing machine, boiler, outdoor lighting); moisture in a circuit after building work or a leak; a damaged cable or socket; or simply too many appliances on one RCD, so small leakage currents add up.
What can you safely check?
Stay away from the wiring, but you can do this without tools: switch off all circuits behind the RCD, then switch them back on one by one. If it trips on one circuit, unplug its appliances and test them individually. If it feels unsafe, leave the RCD off and call an electrician.
Practical information from Oleksandr Volkov, electrical engineer and electrician with 25+ years of experience.