HDB Power Trip: Who to Call and What to Do

The tripped switch is the lever sitting lower than the rest: one MCB down affects one circuit, the RCCB down usually darkens the whole flat.

HDB's home care guide explains the DB box, which HDB calls the consumer unit (HDB: Electrical accessories and wiring). It holds a main switch, a residual current circuit breaker (RCCB) with a test button marked T, and a row of miniature circuit breakers (MCBs), one for each circuit.

Some breakers stop in a middle position when they trip, so the lever looks half up. Push it fully down before you reset it. For the full list of causes, see why the power keeps tripping, or an oven power trip if it happens when one appliance starts.

With dry hands, unplug the appliances on the dead circuit, push the tripped lever fully down, then push it firmly up. Do this once.

1. Dry your hands and use a torch, not a candle.
2. Unplug appliances in the dark rooms and switch off the water heater.
3. If one lever is down, push it fully down, then firmly up.
4. If several are down, switch on the main switch, then the RCCB, then each MCB in turn.
5. Plug your appliances back in one at a time, a minute apart.
6. If the switch trips again straight away, leave it off. Don't reset it a second time, except for the RCCB check below.

The switch-on order in step 4 is the one SP Group gives new BTO owners (SP Group: Pre-turn-on information). If the trip returns when one appliance goes back on, that appliance is the likely cause. Keep it unplugged until it's checked.

The RCCB won't stay up: how do I find the faulty circuit?

This is the one exception to resetting once. Skip it if the box is hot, buzzing or smells of burning, or anything is wet. Switch every MCB off, then switch the RCCB on. If it drops with every MCB off, stop and call an LEW. Otherwise, switch the MCBs on one by one. The one that drops the RCCB is on the faulty circuit: leave it off, restore the rest, and have an LEW trace the leak. For more on this pattern, see RCCB tripping but not the MCB.

Call SCDF on 995 for smoke or a burning smell, and an electrician now if the DB box is hot, buzzes or won't reset.

Otherwise, isolate the faulty circuit and wait for daylight. Once the faulty MCB is off and the rest are on, your fridge and lights usually keep running. Keep the fridge door shut. If someone at home relies on medical equipment, get an electrician straight away, and call 995 if anyone's health is at risk. Ask whether after-hours visits cost more. For the usual night-time causes, see why the power trips at night.

What not to do:

• Don't tape, wedge or hold a breaker in the ON position.
• Don't remove the DB box's inner cover, or open the meter cupboard or the corridor riser.
• Don't throw water on an electrical fire. Call 995.
• Don't swap a breaker yourself. Installing wiring and RCCBs must be done by an EMA licensed electrical worker (MTI: Written reply on electrical installations).

SG QuickFix diagnoses a power trip from $80. A replacement breaker or repair is priced separately after diagnosis.

The price rises when the fault is in concealed wiring or when an intermittent trip needs a return visit. Breaker swaps are handled under circuit breaker and DB box services. For an accurate price, send a photo of the DB box showing which lever is down, and say which rooms are dark and what was running.

Faults on the meter, the corridor riser or common-area wiring aren't part of an in-flat job: those go to SP Group or your town council. Each job is priced separately, so a diagnosis and a breaker replacement are separate items. For other electrical jobs, see the full electrician price list for Singapore.