Why does my ELCB keep tripping?

What the ELCB or RCCB does

The ELCB or RCCB is a safety switch in your distribution board, or DB box. EMA says it cuts off electricity when it detects a current leakage that may lead to an electric shock. It is the switch with a "Test" button, and both names are used for it in Singapore homes.

HDB says the RCCB cuts off electricity in the flat when it detects an earth current leakage. Each single pole MCB protects one circuit and trips on an overload or a short circuit.

If only one MCB has dropped, the problem is on that circuit. If you cannot clear either kind of trip yourself, look for power trip repair.

Common causes when your ELCB keeps tripping

EMA lists three causes of current leakage: ageing or exposed wires, faulty electrical appliances and damaged insulation.

• Faulty appliances. A fault can sit in one appliance, for example one that got wet. The steps below help you find it.
• Ageing wiring. HDB gives the estimated average lifespan of a PVC electrical cable as about 25 years and advises replacing wiring when its lifespan is over or it has deteriorated.
• Damaged insulation. EMA says to replace cords with broken or frayed insulation rather than taping them, and to have cracked or broken power points replaced by an LEW.
• Water near electrics. EMA advises keeping electricity and water apart. If water has reached a socket, an appliance or the DB box, treat it as a hazard and leave it to an LEW.

Find the faulty circuit or appliance

These are practical checks, not an official procedure, and they use only the levers on the front of the DB box.

1. Switch off and unplug. Switch off every appliance at the wall and pull out the plugs, including those on extension sockets.
2. Reset the RCCB. With dry hands, switch the RCCB lever back on. If it goes off again straight away, skip to step 4.
3. Add appliances back one at a time. Plug in and switch on one appliance, wait a minute, then try the next. If the RCCB goes off when one comes on, leave that appliance unplugged and have it checked.
4. Check circuit by circuit. If the RCCB goes off at once with everything unplugged, switch all the MCBs off, reset the RCCB, then switch the MCBs on one at a time. The MCB that sets off the RCCB marks the circuit with the leakage.
5. Leave that circuit off and call an LEW. Keep that MCB off, switch the others back on and ask an LEW to check that circuit.

Once power is back, a home electrical safety checklist can help you spot other worn cords and sockets around the flat.

When the RCCB will not reset

If the RCCB switches off even with every MCB off, you have gone as far as you safely can from the front of the DB box. Leave the power off and call an LEW.

The RCCB itself can also fail. HDB says pressing its test button (labelled T) should switch it off; if it does not, it may be defective. HDB advises engaging a licensed electrician to replace an RCCB that malfunctions.

EMA lists repair or replacement of circuit breakers as work an LEW should carry out or supervise. If the LEW suggests a new unit, see DB box replacement.

Published power trip troubleshooting rates

Three companies in the directory publish a power trip troubleshooting rate, and as printed, all three start at S$50 per job: two print "From S$50 per job" and one prints "S$50 to S$200 per job". The printed scope is to trace and fix one power trip.

FROM THE HOMEZYPRO DIRECTORY

Published power trip troubleshooting rates

For the most common unit (per job), the lowest published power trip troubleshooting rates from 3 companies run from S$50 to S$50 per job (middle rate S$50), to trace and fix one power trip. The middle figure is a real published rate, not an average. Each figure is one company's own advertised rate with its conditions, not a quote.

See 3 published power trip troubleshooting rates and sources

Lowest matching advertised rate per company, in SGD as published. "From" marks a starting price and ranges are shown in full. Check the source for minimums, GST and inclusions.

Company	Service as listed	Rate	Source
Lito Electrical Service	Power Trip Troubleshooting	From S$50 per job	litoelectrical.com
Repair.sg	Resolve power trip	From S$50 per job	repair.sg
Sin & Goh Electrical Engineering	Power trip troubleshooting	S$50 to S$200 per job	wireman.com.sg

The final charge depends on what the electrician finds, and any repair or part is extra unless the company says otherwise. For other electrical jobs, see electrician costs in Singapore.

When to stop and call a professional

Stop resetting and call an LEW if you notice any of these:

• A burning smell, or scorch marks on a socket, a switch or the DB box.
• Water in the DB box or in a socket.
• The RCCB tripping again and again with no appliance plugged in.

HDB lists burnt marks at a socket as caused by a plug not fully inserted or an overloaded circuit, and notes that only a licensed electrician can replace socket outlets.

EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. EMA says to verify the LEW's licence card, which carries a photograph and licence number, before any work starts. You can also search for licensed workers on EMA's ELISE portal.

For a trip at night that you cannot clear, look for 24-hour electricians.

Questions