Quick answer
Power usually trips at night because something runs unattended (the aircon, a fridge's automatic defrost heater or a water heater left switched on) or damp reaches an outdoor point as humidity peaks before dawn. Note the time and which DB switch dropped each time. In Singapore, SG QuickFix diagnoses power trips from $80.
SG QuickFix pricesTap to WhatsApp
| Power trip diagnosis | From $80 |
| Appliance-related trip diagnosis | From $80 |
| Circuit fault tracing | From $100 |
| Complex concealed wiring fault | Quote after diagnosis |
Current SG QuickFix starting prices. Final price confirmed before work begins.
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Why does my power trip at night?
Power trips at night because something is still running while you sleep, or damp has reached a worn cable or fitting.
Two kinds of switch in your DB box do the tripping. According to HDB, an MCB trips on "overcurrent due to an overload or short-circuit", while the RCCB cuts off electricity in your flat when it detects earth current leakage (HDB: Electrical accessories and wiring). With little running at night, overload is unlikely, so the RCCB is usually the switch that drops.
The Energy Market Authority (EMA) and HDB say leakages "are caused by ageing or exposed wires, faulty electrical appliances, and damaged insulation" (EMA and HDB: RCCBs required in all homes). A trip log usually shows which appliance or fitting leaks. If it doesn't, power trip diagnosis traces the fault circuit by circuit. For MCB and RCCB basics, see why power keeps tripping.
What switches on by itself while you sleep?
Your aircon, fridge, a water heater left on and anything on a timer all run unattended, and each can leak current or overload a circuit.
| Suspect | Why it trips at night | Switch that usually drops | Clue in your log |
|---|---|---|---|
| Fridge or freezer | Its defrost heater switches on by itself; a worn element leaks current | RCCB | Trips at a regular interval, day or night |
| Aircon | Runs for hours; a faulty compressor, or a blocked drain dripping onto wiring | RCCB, sometimes its own MCB | Trips only on nights the aircon is on |
| Water heater left switched on | A storage heater reheats on its thermostat; a leaking element trips it | RCCB | Trips stop when the heater is off overnight |
| Washer or dryer on a delay timer | Its heater or motor starts while you sleep | RCCB, or an MCB if it shares a busy circuit | Trips around the time the timer was set |
| Yard, balcony or corridor-facing points | Damp gets into a socket, light or cable | RCCB | Trips on humid or rainy nights |
| Many small devices | Chargers and electronics each leak a little; it adds up | RCCB | No single appliance repeats; trips look random |
LG says its fridges defrost automatically every 4 to 16 hours, so a fridge fault can trip the power at 3am one night and mid-afternoon the next.
The Consumer Product Safety Office (CPSO) advises switching off the water heater when it isn't in use, to prevent overheating of its components or wiring (CPSO: Safety tips on water heaters). If trips stop once you do, see the guide to a water heater that keeps tripping.
The main switch rarely trips at night: it limits the flat's total current, which peaks in the evening, not at 3am.
Can humidity or rain trip the power at night?
Yes. Singapore's air is at its dampest just before dawn, and some storms arrive in the small hours.
The Meteorological Service Singapore (MSS) says night temperatures usually don't fall below 23 to 25°C, but relative humidity often exceeds 90% in the morning just before sunrise (MSS: Climate of Singapore). Night trips are about moisture, not cold. MSS also notes occasional Sumatra squalls between the predawn hours and midday during the Southwest Monsoon (June to September), wetting outdoor sockets, lights and aircon condensers.
Damp rarely trips healthy wiring; it tips over ageing insulation or a cracked fitting. HDB puts the lifespan of PVC cables at about 25 years, so original wiring in older flats is more exposed.
A 30 mA home RCCB, the sensitivity EMA requires, can trip well below 30 mA, so small leaks from several appliances plus one damp point can trip it. If trips come mainly with storms, see power trips during a thunderstorm.
How do I keep a trip log that finds the cause?
Write down every trip for a week or two: when it happened, which switch dropped, the weather, and what was running.
For each trip, note:
- The date, and the time you noticed it.
- Which lever was down: the RCCB (with the "T" button), one MCB, or the main switch.
- The weather: dry, humid, raining or a storm.
- What was on or on a timer: aircon, water heater, washer, dryer, chargers.
- Whether it reset first time or tripped again straight away.
After three to five entries, a pattern usually appears:
- A regular interval, day and night: suspect the fridge.
- Only with the aircon on: the aircon or its circuit.
- Only with the water heater left on: the heater.
- Only on wet or humid nights: an outdoor or yard point, or ageing wiring.
- No pattern, several appliances running: combined leakage or an ageing RCCB. See RCCB tripping but not the MCB.
Show the log to your electrician.
What can I safely do tonight until morning?
Reset once, leave the circuit that trips again switched off, and keep the fridge's circuit on so food stays cold.
- Switch off the water heater and aircon at their isolator switches.
- Switch all single-pole MCBs down.
- Push the RCCB, or the main switch, back up.
- Switch the MCBs up one at a time.
- If one trips it again, leave that MCB down and reset the rest.
- If the fridge's circuit is the one that trips, unplug the fridge and try that circuit again.
- If the RCCB won't stay up with every MCB down, leave it off until morning.
If the circuit holds with the fridge unplugged, the fridge is the likely cause. Keep its door shut: a closed fridge stays cold for a few hours. Running it from another room on an extension lead usually just trips the RCCB again. See who to call for an HDB power trip.
Mistakes that make night trips worse:
- Resetting again and again, or taping or holding the lever up.
- Plugging a water heater into an extension lead: CPSO says not to power it from extension cords or multi-way outlets.
- Opening a damp socket yourself: HDB says only a licensed electrician can replace socket outlets.
How much does it cost to fix night-time power trips in Singapore?
SG QuickFix diagnoses power trips from $80; repairs and parts are priced separately.
| Job | When your log points to it | SG QuickFix price |
|---|---|---|
| Power trip diagnosis | Trips keep coming back with no clear pattern | From $80 |
| Appliance-related trip diagnosis | Trips follow the fridge, aircon or washer | From $80 |
| Circuit fault tracing | Trips on humid or rainy nights, or with only hard-wired loads on | From $100 |
| Water heater diagnosis | Trips stop once the heater is switched off | From $80 |
| RCCB / RCD replacement | The RCCB fails its "T" test, or trips with every circuit healthy | From $180 |
Faults in concealed or false-ceiling wiring take longer to trace and cost more. An intermittent night fault may need a second check if nothing trips during the visit. For an accurate price, send a photo of the DB box showing which lever is down, plus your trip log. See water heater services, circuit breaker and DB services and the full electrician price list for Singapore.
| Safe to DIY if… | Call a professional if… |
|---|---|
| It tripped once and stays up after one reset | It trips on more nights, or again straight after reset |
| One MCB stays down and the rest of the flat works | The RCCB won't stay up with every MCB down: licensed electrical worker |
| You are keeping a trip log and pressing "T" monthly | Your log points to one appliance, an outdoor point or ageing wiring |
| Don't remove the DB box's inner cover, open sockets or change a breaker yourself | You smell burning or see scorch marks, heat or water near the DB box |
What happens when you WhatsApp us?
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Electrical Troubleshooting / Power Trip
From $80
- Fault finding
- Short-circuit repair
Electrical Troubleshooting / Power Trip FAQs
A power trip at the same time every night usually follows something on a schedule: a washer or dryer on a delay timer, a smart plug, or a storage heater's thermostat reheating the tank. Switch off one scheduled appliance at a time for a few nights; if the trips stop, that appliance or its circuit is the likely cause.
Something is always on at night: the fridge, router, chargers and appliances on standby. Their small leakage currents add up on the RCCB, and damp before dawn can push an ageing cable or fitting over the edge. If it keeps happening, have a licensed electrical worker test each circuit.
No. Singapore's Consumer Product Safety Office advises switching off the water heater when it isn't in use, to prevent overheating of its components or wiring. If night trips stop once the heater is off, have the heater's element and wiring checked rather than just leaving it off.
Usually, if the power stays on after one reset with the faulty circuit left off, and there is no burning smell, heat, buzzing or water near the DB box. If you smell burning, don't touch the DB box; if there is smoke or fire, get everyone out and call 995.
Sometimes, but most unexplained night trips are real leakage from an appliance, a damp point or ageing wiring. An ageing RCCB can also nuisance-trip or fail to trip. HDB advises testing it monthly: switch off computers, then press "T". If it doesn't switch off, have a licensed electrical worker replace it. SG QuickFix replaces an RCCB from $180.
SG QuickFix diagnoses power trips in Singapore from $80, and repairs and parts are priced separately. Faults in concealed or false-ceiling wiring take longer to trace and are quoted after diagnosis. Sending a DB box photo and your trip log helps give an accurate price.
Related services
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View serviceServing Bedok, Pasir Ris, Punggol, Sengkang and Tampines and island-wide.
Sources & updates
- HDB: Home care guide, electrical accessories and wiring, checked 1 Oct 2026
- HDB: Residual current circuit breakers required in all homes (11 May 2023), checked 1 Oct 2026
- MTI (now METI): Written reply to PQ on Electrical Installations Regulations (4 Apr 2022), checked 1 Oct 2026
- Consumer Product Safety Office (CPSO): Safety tips on water heaters, checked 1 Oct 2026
- Meteorological Service Singapore: Climate of Singapore, checked 1 Oct 2026
- EMA: Circular RD/E01/2023 on RCCBs in residential premises (May 2023, PDF), checked 1 Oct 2026
- SCDF: Emergency hotline 995 (fire, rescue, emergency ambulance), checked 1 Oct 2026
- Updated 1 Oct 2026: First published
Related guides
RCCB Tripping but Not the MCB? How to Find the Earth Leakage
When the RCCB trips but no MCB does, current is leaking to earth: a few milliamps, too little for an MCB. In Singapore it's often a water heater or damp socket. Unplug everything, switch MCBs off, reset the RCCB and turn MCBs on one by one; stop if it trips with all off. SG QuickFix diagnoses power trips from $80.
Updated 28 Oct 2026 · 7 min read
Power Keeps Tripping? MCB vs RCCB and How to Find the Cause
When power keeps tripping in a Singapore home, a DB box switch is cutting off a fault: an MCB trips on overload or short circuit, the RCCB on earth leakage. With dry hands, switch all MCBs off, reset, then turn them on one by one and leave off the one that trips. SG QuickFix diagnoses power trips from $80.
Updated 12 Oct 2026 · 7 min read
Power Trip During a Thunderstorm: Normal or a Fault?
An occasional power trip during a thunderstorm in Singapore is usually normal: lightning causes a brief leak the RCCB treats as a fault. Wait until the lightning passes, unplug electronics and reset once. If it trips every time it rains, water is reaching a socket, light or cable in your HDB flat. SG QuickFix diagnoses power trips from $80.
Updated 8 Oct 2026 · 6 min read
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This guide is general information for homes in Singapore. It is not professional, legal or safety advice for your specific situation. Electrical, gas and some plumbing work can be dangerous, and Singapore law requires certain jobs to be done by licensed workers. Any work you carry out yourself is at your own risk, and SG QuickFix accepts no responsibility for any loss, damage or injury arising from the use of this information. Prices shown are current starting prices, may change, and the final price is confirmed before any work begins. Rules and figures from HDB, PUB, EMA, SP Group and town councils were correct when last checked; please confirm with the relevant authority before acting.