The most common cause. Running several high-draw appliances on one circuit at once — kettle, oven, water heater, hairdryer — overloads it, and the MCB cuts power to protect the wiring. Spreading the load across different sockets/circuits usually fixes it; if it keeps happening, you may need a dedicated circuit added.
A loose wire or a faulty appliance lets live and neutral touch, so the DB box cuts power instantly to prevent a fire. The tell-tale sign is a single MCB that trips the moment you reset it, even with nothing plugged in — that points to fixed wiring, not an appliance, and needs an EMA licensed electrician.
In Singapore, old storage water heaters frequently cause Earth Leakage Circuit Breaker (ELCB) trips due to water seeping into electrical components.
Reset the breaker once. If it trips again immediately — especially the wider RCCB/ELCB switch — stop and do not force it; that switch is your shock and fire protection. Note which breaker trips and whether it happens with everything unplugged, then get an EMA licensed electrician to trace and fix the fault safely. Same-day diagnosis is usually possible across HDB, condo and landed homes.
How to Find the Tripping Circuit Yourself (Safely)
Before you call anyone, you can narrow down the fault with a simple isolation test at your DB box (distribution board). This works the same whether you live in an HDB flat, a condo, or a landed home — most Singapore DB boxes have one main switch plus a row of labelled MCBs (Miniature Circuit Breakers) and at least one RCCB/ELCB (the wider switch that protects against electric shock and earth leakage).
- Unplug everything on the affected area — fridge, kettle, water heater, washer, chargers, the lot.
- Switch OFF every MCB, then reset the main switch and the RCCB so power is restored to the box.
- Flip MCBs back on one at a time. The breaker that trips when you switch it on (with nothing plugged in) points to faulty fixed wiring or a built-in fitting.
- If all MCBs hold, plug appliances back one by one. The appliance that causes the trip is your culprit — stop using it and get it checked.
If the trip is on the RCCB/ELCB rather than a single MCB, that almost always means earth leakage — current escaping to earth, often through a wet water heater element, a damp outdoor socket, or aged wiring. That is a shock hazard and the one fault you should not keep resetting.
A 4th Common Cause in Singapore: Moisture & Outdoor Sockets
Our humidity is brutal on electrics. Service-yard sockets, balcony points, and bathroom heater isolators collect condensation and corrosion, and a single damp connection can trip the whole RCCB after a rainy night. If your power only trips during storms or after using the yard washing machine, suspect moisture ingress rather than an "overload".
DIY vs Calling an EMA Licensed Electrician
You can safely do the unplug-and-reset isolation above, swap a tripping appliance, and reset a breaker once. You should not open the DB box cover, replace an MCB/RCCB, rewire a socket, or repeatedly force a breaker that keeps tripping — under Singapore's Electricity Act, fixed electrical work must be carried out by an EMA Licensed Electrical Worker. Forcing a tripping RCCB defeats your shock protection and is the single most dangerous shortcut homeowners take.
| Symptom |
Likely cause |
Typical fix & indicative cost |
| Trips only when kettle + oven + heater run together | Overloaded circuit | Redistribute load or add a dedicated circuit — electrician callout from ~S$80 |
| One MCB trips instantly with nothing plugged in | Short circuit in fixed wiring or a socket | Trace & repair wiring / replace socket — typically from ~S$120 |
| RCCB/ELCB trips when water heater is switched on | Earth leakage from wet heater element | Isolate & service/replace heater element — from ~S$120, plus heater part |
| Whole-house trip after rain / from yard socket | Moisture / corroded outdoor point | Dry, reseal or replace point — from ~S$90 |
| Old MCB/RCCB nuisance-tripping repeatedly | Worn breaker | Breaker replacement — from ~S$80 per breaker, confirmed on site |
Prices are indicative and confirmed on site after inspection — actual cost depends on access, parts, and the extent of fault-tracing. See our full electrician cost guide and the searchable FixMove price index for current ranges.
Frequently Asked Questions
Is it safe to keep resetting a breaker that trips?
Resetting once to confirm it was a momentary spike is fine. But if it trips again immediately — especially the RCCB/ELCB — stop. Repeated tripping means a real fault, and forcing it bypasses your shock and fire protection. Isolate the affected circuit and call an EMA licensed electrician.
Why does my HDB power only trip when I use the water heater?
Older storage heaters in Singapore develop micro-cracks that let water reach the heating element, causing earth leakage that trips the ELCB/RCCB. The fix is to isolate the heater, then service or replace the element or the unit. Until then, keep that heater switched off at the isolator.
Do I legally need a licensed electrician in Singapore?
Yes. Any fixed electrical work — replacing breakers, rewiring, installing sockets or DB box work — must be done by an EMA Licensed Electrical Worker under the Electricity Act. Homeowners may only do basic, non-fixed tasks like unplugging appliances and resetting a breaker.
How much does it cost to diagnose a power trip?
A diagnostic callout in Singapore typically starts from around S$80, with repairs such as socket replacement, wiring repair, or breaker changes confirmed on site after the fault is traced. Whole-circuit or DB box work costs more depending on scope.
Tripping that won't stay reset is your home's safety system doing its job — don't override it. For a same-day diagnosis by an EMA licensed electrician, learn more on our electrical services hub or message us on WhatsApp for an indicative quote.