Your earth leakage trips, you push it back up, and a few minutes or hours later it trips again. Sometimes it won’t go back up at all. It’s one of the most common electrical calls we get in Johannesburg, especially in summer when the afternoon storms arrive.
The good news: an earth leakage that trips is doing its job. Something is leaking current, and the device is protecting you from a shock or a fire. The aim is to find that something.
What an earth leakage unit does
An earth leakage unit compares the current flowing out on the live wire with the current coming back on the neutral. If they don’t match, some current is escaping, usually to earth through a damp fitting, damaged insulation, or a person. When the difference reaches the trip level, typically 30 mA in a home, it switches off within a fraction of a second.
That’s different from a circuit breaker, which trips when a circuit draws too much current. If you’re unsure which one is tripping, look at the DB board. The earth leakage is usually the wider switch with a test button.
The most common causes
1. A faulty geyser element
This is the number one cause we find. Geyser elements sit in hot water all day, and Johannesburg’s hard water coats them in scale. Eventually the element’s casing cracks and current leaks into the water. Typical sign: it trips when the geyser switches on, for example when the timer kicks in or after you’ve used a lot of hot water.
2. Damp in outside plugs, lights and pumps
Garden lights, outside plugs, pool pumps and electric fences all get wet. Typical sign: it trips when it rains, or overnight when dew settles.
3. A faulty appliance
Kettles, washing machines, dishwashers, ovens and fridges can develop faults that leak current. Typical sign: it trips when a particular appliance switches on.
4. Old or damaged wiring
Perished insulation in older homes, cables chewed by rats in the roof, or a nail through a cable. Typical sign: it trips even with everything unplugged.
5. After load shedding or a power cut
Some homes trip every time power comes back. Several appliances switching on at once can add up enough small leakage currents to trip the unit. A surge can also damage the earth leakage unit itself.
6. A worn-out earth leakage unit
Earth leakage units age. An old one can become oversensitive and trip without a real fault, or fail to trip when it should. If it doesn’t trip when you press the test button, it needs replacing urgently.
How to find the faulty circuit safely
You can narrow the problem down yourself without opening anything:
- Unplug everything in the house that’s on a plug.
- Switch off every circuit breaker at the DB board, but leave the main switch and earth leakage on.
- Push the earth leakage back up.
- Switch the breakers on one at a time, waiting a minute between each.
- When the earth leakage trips, the last breaker you switched on is the faulty circuit.
- If the plug circuits are fine, plug appliances back in one at a time to find a faulty appliance.
Write down which circuit or appliance caused the trip. It saves time and money when the electrician arrives.
Stop and call an electrician if:
- The earth leakage trips with every breaker off
- You smell burning or see scorch marks
- There’s water near the DB board
- The trip is on the geyser circuit, because the geyser element and wiring need proper testing
What an electrician does
- Insulation resistance testing on each circuit, which shows damaged wiring that looks fine
- Testing the geyser element and thermostat
- Checking outside fittings for water getting in
- Testing the earth leakage unit to check it trips at the right current and speed
- Fixing the fault, whether that’s a new element, sealed fittings, a repaired cable or a new unit
Can I just replace the earth leakage with a less sensitive one?
No. A 30 mA earth leakage unit is required in homes because it protects people from electric shock. Fitting a less sensitive unit, or bypassing it, removes that protection and will fail a COC inspection. The fix is always to find the leak.
Summer storms and earth leakage
Highveld thunderstorms from October to February bring the most earth leakage calls. Rain finds its way into outside plugs, garden lights, pool pump housings and cracks in exterior walls. Lightning surges damage earth leakage units too. If you have trips every time it rains, have your outside fittings checked and sealed before the season.
Need it fixed?
If you can’t find the cause, or the trip is on your geyser or wiring, call a licensed electrician. Supa Nova finds earth leakage faults in homes across Johannesburg. See emergency electrician, or call 011 485 1324 or 082 891 1577.
Related: Why circuit breakers trip