Half the house has no power, or the voltage is wrong: what's TNB's and what's yours

When part of a house goes dead and no breaker has tripped, the cause is usually one of two things. Either a phase is missing (on a three-phase house, often TNB’s cut-out fuse at the meter) or a neutral has broken somewhere. A missing phase just turns things off. A broken neutral is the dangerous one: it can push some circuits far above 230 volts and destroy whatever is plugged in.

So the useful first questions are: is it only your house, is anything glowing brighter or spinning faster than it should, and is the problem before or after TNB’s meter? This guide works through the symptoms Malaysian homeowners and wiremen keep posting about in electrical Facebook groups. We checked them against Energy Commission (ST) and TNB documents.

First five minutes: what you can safely check

1. Look at the neighbours. If they’re dark too, it’s a supply outage: report it to TNB on 15454 (call, or SMS BD to 15454 from a registered number). TNB’s own advice is to check the neighbours first and call only once you know it’s TNB’s side. It estimates about 60% of festive-season outage calls were faults in the customer’s own wiring.
2. If lights are unusually bright, bulbs are popping or fans are racing, switch off the main switch now. That’s the signature of a lost neutral or a badly high supply. Every minute it runs, more electronics die. Then call 15454 and an electrician.
3. Open the DB cover and look, don’t poke. Is any MCB or RCCB down? If an RCCB has tripped, follow our RCCB tripping guide. Reset a tripped device once. If it trips again, leave it off.
4. Look at the meter display. If the meter is on but the whole house is dead, the fault is after the meter: the cables to the DB or the main switch. On a three-phase house with only some circuits dead, the meter can stay on with one phase missing, and a blown cut-out fuse on that phase is common.
5. Don’t touch the cut-out fuses or the neutral link next to the meter. They’re TNB’s property, sealed, and live even with your main switch off. TNB states plainly that changes to its meter or fuse are prohibited. Members who called TNB about a blown or loose cut-out report it was replaced free, sometimes within the hour, though others waited much longer (a few say a stolen fuse may be charged).

Everything past that — opening terminals, measuring inside the DB, lifting neutrals — is a wireman’s job. The ST list of registered electrical contractors shows who is entitled to do it.

Who owns what

The boundary sits at the meter. On a typical house:

TNB’s supply terms say everything “up to and including the meter will be the property of TNB”. Its Electricity Supply Application Handbook says the applicant “must provide wiring from cut-outs and neutral link to meter”. That’s why wiremen argue about those short tails. In one 368-reaction thread about perished cut-out-to-meter cables, the answers split three ways: “anything before the meter is TNB’s”, “TNB only does up to the cut-out, hire a wireman”, and the practical route several electricians described. That route: report it on 15454, let TNB open the seal, have the cables replaced, then TNB reseals. Some members said TNB replaced burnt tails itself for free; others were told by TNB it wasn’t its job and to hire a wireman. Don’t let anyone cut the seal without TNB knowing. Tampering with TNB’s installation is an offence under the Electricity Supply Act.

In condos and stratified shops, the meters sit in a riser room that management controls. In one condo thread about a missing cut-out fuse, management insisted its own technician would fit it. Members replied that the fuse is TNB’s and TNB replaces it free, but only management can let anyone into the riser room.

Lights dead, sockets fine (or the other way round)

Most homes have lights and fans on 6A or 10A MCBs and sockets on 20A ones, sometimes on separate RCCBs. If one group is dead:

• A tripped or failed MCB. An MCB can look ON and pass nothing. In a whole-house blackout, a JB electrician found the 63A main MCB looked switched on but had failed inside; a new one restored power. A circuit MCB can fail the same way.
• A broken neutral or live on that circuit. In a 59-comment thread about every light being dead while fans and fridge worked, several electricians said check the lighting MCB, then the circuit’s neutral. One had traced the same symptom to rats chewing through the neutral in the ceiling, which killed a whole lighting circuit.

A socket shows live on the tester but nothing works

This one comes up again and again, and the replies overwhelmingly point to the neutral not getting back. A test pen only shows that live is present. With no neutral, nothing flows. In a 170-reaction thread, the owner said every connection was “ketat dan padat” (tight and solid). The top replies said the neutral is broken somewhere upstream, often at another socket on the same loop or at the DB. The other suspect was a terminal screwed down on the insulation instead of the copper; one reply suggested neutral and earth swapped at the socket.

One reply explains a tester trick that confuses people. With nothing plugged in, the neutral shows dead. Plug something in and switch it on, and the neutral pin lights the tester, because the appliance connects it through to live and there’s no return path. A neutral that lights a tester under load is broken further back.

Real cases from the groups:

• An owner installing his own downlights in a new unit found one point dead. The fault was a neutral loop left disconnected at a fan point not yet installed. The owner had been about to call someone in to open the plaster ceiling.
• A water heater that wouldn’t start had a loose neutral at its own wall switch.
• A kitchen light glowed dim and only went bright when the living-room switch was turned on. A couple of electricians called it a shared or borrowed neutral between two circuits (“curi neutral”). Each circuit’s neutral must go back with its own live, and through the same RCCB.

A loose neutral is also a fire risk at the terminal. Our DB fire guide shows what that looks like once it has burnt.

Half the house dead on a three-phase supply

A three-phase house splits its circuits across red, yellow and blue (in newer wiring, brown, black and grey). Lose one phase and roughly a third of the house goes dark with no breaker tripped.

The groups’ first answer is right more often than not: check whether one phase is missing at the meter, then report it. Cases:

• Sentul, KL: some sockets alive, some dead, all breakers up. The red phase had no supply because its cut-out fuse had blown; TNB came and replaced it.
• A neighbour’s house went dark after heavy lightning. The red phase still worked, but the blue and yellow cut-out fuses had blown, and TNB was called to replace them. The same owner also mentioned a tingle from the fridge, so the electrician wanted the earthing checked too.
• A JB shop lost a phase. TNB came and confirmed its supply was fine, so the fault was inside: the shop’s 63A three-phase isolator had failed internally and dropped one phase.
• A JB electrician reported one phase about 40V lower than the other two, with aircond not cooling. The middle phase’s cut-out fuse had burnt and its holder was carbonised.

A cut-out that blows once can be a fault in the house. When one owner’s cut-out kept blowing at night with no leakage found, nearly every reply blamed overload and said to measure the evening load against the cut-out rating. The cause turned out to be a damaged incoming cable. So check the cable as well as the load. Our single- vs three-phase guide covers how loads should be balanced.

Bulbs blowing, fans racing, appliances dying: the lost neutral

This is the fault people most need to recognise. In a three-phase supply each phase is 230V to neutral and 400V between phases. The neutral is the shared return that holds every circuit at 230V. If the neutral breaks, circuits on different phases end up in series across 400V. The voltage then divides by load. A lightly loaded phase (a few LED bulbs, a phone charger) can rise towards 400V. A heavily loaded one (aircond, water heater) sags. So lights flare and pop and fans race, while big loads struggle.

It happens in two places:

• Inside a three-phase house: a loose or burnt main neutral at the meter board, neutral link or DB. A kakirepair member posted a burnt neutral at a three-phase meter board, with the meter’s alarm LED lit, after several bulbs burst at once. (A loose neutral at a DB does damage on any supply: a Shah Alam wireman reported one that ended with flames at the board and four fans and 22 lamps replaced.) After a single-to-three-phase upgrade, one owner measured 223V on one phase and “4++V” on the other two at his DB, with lamps “terang sampai meletup”. TNB measured normal voltage at the meter. Replies said a neutral that isn’t connected, or a phase landed in the neutral position, gives exactly that. This was on new cables he had bought for the upgrade.
• On the street, hitting single-phase houses too. Terrace houses are spread across the three phases and share the street neutral. If that neutral breaks at a pole joint, feeder pillar or during works, houses on different phases end up in series and the lightly loaded ones get the high voltage. One member’s photo shows 361.6V on a clamp meter at a single-phase house’s cut-out after the fridge, wifi router, bulbs and fans died. In another thread a member described 480V, with TNB finding the neutral broken at the pole. In a third case, a wireman diverting a house’s service cable connected live before neutral. The electrician called out to fix it said that floated the neutral and damaged appliances in several houses. A weak IPC joint left from an earlier diversion sparked and burnt, which he thought stopped more houses being hit. And one member said TNB “accidentally mixed their cables” during street repairs, leaving fans running fast until a night visit found it.

A couple of replies in the 361.6V thread made the useful distinction: a neutral break inside a single-phase house just cuts the power, but a break in the shared street neutral can push voltage high and usually hits several houses at once.

What to do: main switch off, unplug sensitive electronics, call 15454 and say the voltage is high and appliances are being damaged. Ask neighbours whether their lights did the same. Then have an electrician measure each phase to neutral, phase to phase, and neutral to earth at the meter and at the DB. That tells you which side the break is on. If the meter side is fine and the DB is high, the fault is in your own cables.

Steady 250–260V, or dim lights at night

Not every voltage complaint is a broken neutral. ST’s domestic wiring guideline (section 5.1) and the Distribution Code (DPC 5.4.4) set the supply at 230V single-phase / 400V three-phase, +10% / −6%. That works out to 216–253V per phase and 376–440V between phases. Before 2008 the declared supply was 240V (+5%/−10%), which is why some members still say “240V is normal”.

So 242V is fine, and dozens of members said so when a landlord’s tenant blamed a smoking TV on it. Readings above 253V are out of spec, and a night-time climb matters when it crosses that. Cases:

• 253V at home and 260V at a relative’s shop, with two fridges dead at each.
• 257–260V. TNB measured 253–257V and said lowering it might affect other houses.
• 260V at a plug, 258V at the DB and the cut-out. TNB agreed it was over-voltage and said it would re-tap the substation transformer.
• On a three-phase house, an AVR kept cutting the TV at 255V. TNB adjusted the supply down to about 245V, it crept back up, and only after several visits did it settle around 241V.
• 214V at the meter with lights dim at night. TNB moved the house to another phase, which gave 230V by day but still 213V at night. A reply said that’s an area problem: get the neighbours to report too. Elsewhere, wiremen posted TNB discussing a new compact substation for an area with voltage drop.

Lights dimming for a moment when the aircond starts can be normal on a long line. When it comes with buzzing or sparking at the meter board, it’s a loose connection. One owner traced lights flickering whenever the water heater ran to a loose, non-original cut-out carrier sparking under load. TNB came quickly and fixed it. If it’s only one circuit dimming, have an electrician check for a shared neutral or an undersized long run. ST allows 3% voltage drop on lighting circuits and 5% on others.

Measure properly before you complain. Plug-in socket testers read a few volts off. Members found 3–9V differences against a multimeter, and TNB told one owner their tester wasn’t accurate. Smart meters show voltage too. Photograph the reading, the time and the meter.

A surge protector won’t fix this. An SPD diverts spikes lasting microseconds, like lightning; it isn’t built for hours at 260V. Electricians in the groups recommend an over/under-voltage protection relay in the DB, which cuts supply when voltage leaves a set band. Some use an AVR for a TV or PC. Both protect your equipment. Neither fixes the supply, so report it as well. Our SPD page explains what surge protectors do cover.

Tingles and shocks from the fridge, washer or taps

A tingle from a fridge, washing machine, rice cooker or metal roof means current is leaking somewhere and its path to earth is missing or broken, or the RCCB isn’t doing its job. Electricity Regulations 1994 reg 34 requires the metal frame of fridges, cookers and other appliances to be effectively earthed. A water pipe can’t be the only earth.

The cases show both halves of the problem:

• A leaking appliance hidden by a bypass. A family’s RCCB kept tripping. Their first wireman replaced it, then added a wire in the DB that stopped the trips. Three weeks later a child touched the fridge and felt current. A second wireman tested properly, removed the bypass and fitted a new RCCB. The trips came back whenever the fridge was on, so the fridge was the leak all along.
• A disconnected earth. One owner found the earth cable from the earth pit wasn’t connected to the DB’s earth bar; the fridge body lit the tester. Another electrician traced shocks from a rice cooker and laptop to a loose earth terminal at a kitchen socket. A third found a house with no earth at all after 12 years, even though two technicians had added sockets in that time.
• The wrong RCCB. A house with two 300mA RCCBs gave a shock without tripping. 300mA is an industrial and fire-protection rating. Regulation 36 calls for 30mA where hand-held appliances are used, 100mA for other circuits and 10mA in wet locations.
• Outside the house. A Shah Alam aircond installer got a shock from a metal gutter. His team found a rooftop solar cable laid directly against it, and said years of rubbing and weather could wear through the insulation and make the gutter live. ST’s investigation of the 2022 Bangi deaths found two brothers killed after one held a clothesline pole attached to a live zinc roof. ST’s advice: report sagging service lines or lines touching a roof to 15454 or ST.

Should you call a fridge technician or a wireman? A popular reply said fridge leakage is the technician’s job. Most electricians said check the earth first. Both causes turned up in the outcomes. A leaky appliance only gives a tingle when its earth path is missing; the RCCB limits how long a shock lasts, and only a 30mA one is meant to protect people. So stop using the appliance and have the house’s earth and RCCB tested. Then test the appliance on its own: if it trips a known-good RCCB, it’s the appliance. Our earthing guide covers earth resistance (under 200 ohms for an RCD-protected home) and why a socket tester alone can’t confirm it.

Neutral–earth voltage is the other thing members measure. A few volts is normal. One three-phase owner saw under 2V by day and 8–10V late at night. A JB owner had 20V after a broken-neutral incident. High or rising N–E points to a loose neutral, a poor earth, or the street network. An electrician checks the DB and meter connections first, then takes the readings with times to TNB.

Test pens glowing on neutral or earth aren’t always a fault. A test pen can light on a few volts, and a neutral that runs alongside other live cables can pick up that much by induction. A pen that glows on a neutral under load, though, means a broken neutral further back. A multimeter settles which one you have.

Complaining to TNB and claiming for damage

Reporting. Outages and dangerous supply faults go to 15454, 24 hours. The 1300-88-5454 number is for billing. Get a ticket number. ST’s rules oblige TNB to test when you report a voltage problem, and to fix voltage that’s within its control (Distribution Code 6.6.2). An ST FAQ says unstable or high incoming voltage is the licensee’s to repair. If TNB finds it normal, the house wiring or appliances are the likely cause.

Timelines. ST’s performance standard for TNB (TNB’s summary) gives TNB 30 working days to investigate an over-voltage complaint, 14 days to report on a voltage sag, and up to 180 days to fix a voltage problem that needs network work. These are service levels, not rebates. The only rebates, which you have to claim, are for outages, connections and wrongful disconnection: for example 1% of the monthly bill (at least RM10) when a low-voltage outage takes over three hours to restore, claimed within two months.

Damage claims. Members are sure you “boleh claim” when TNB is at fault. The outcomes they report are mixed:

• one household hand-delivered a claim letter listing a fridge, washing machine and microwave and has had no reply in 13 years (the most-liked comment in that thread);
• one member says TNB paid for replacements and repairs after they complained to the Energy Commission, and another says a TNB officer who inspected promptly offered about RM9,000, paid within a month;
• another says TNB staff assessed losses after a surge when power came back from an outage and reimbursed about RM7,000, with a neighbour getting more than RM20,000;
• another says their claims were rejected years ago;
• TNB staff told a landlord that damage caused by high voltage could be compensated.

TNB’s supply contract (clause 29) says it isn’t liable for damage from “voltage fluctuation” unless its negligence or a wilful act is proven. So a claim is a case you have to make; there’s no automatic payout. What members advise, and what makes the case:

• photos or video of the voltage reading, with time and place (meter board and DB);
• TNB’s ticket number and what its team found (for example a broken neutral at the pole);
• a list of damaged items with model and serial numbers, repair quotes or invoices with a company stamp, and the damaged items kept;
• the neighbours’ complaints, if several houses were hit;
• an electrician’s report showing your own wiring was sound. Several members also make a police report.

If TNB doesn’t resolve it, escalate to ST’s complaint channel with the TNB ticket number. ST asks for it and may reject a complaint without it. The Electricity Supply Act keeps other legal remedies open, including the Consumer Protection Act. Our TNB bill guide covers the same complaint route for billing disputes.

What it costs to have it found

From troubleshooting discussions in Malaysian electrician and home-repair Facebook groups in 2026 (reported prices, not quotes):

• Callout to find a fault: answers ran from RM90–150 for a quick check, to RM200–300, RM250 per phase, and RM500 for a full troubleshoot. A JB advertiser listed RM250 for a professional trip inspection.
• Cut-out fuse: members report TNB replaced it free. One member said a wireman would charge at least RM150 for the same job.
• Splitting a house onto 30mA and 100mA RCCBs: “RM1k ke atas” (one comment).
• Whole DB replacement after repeated night outages in a condo: RM1,800. A commenter thought a new RCCB alone would have done; our DB upgrade guide has more quotes.

Warning signs worth acting on

• Lights flaring brighter, bulbs and LED drivers failing in batches, fans speeding up: lost neutral or high voltage. Main switch off, then call.
• Buzzing, crackling or a burning smell at the meter board or DB, or flicker every time a heavy load starts: loose cut-out or terminal.
• A neutral that lights a tester, or neutral–earth voltage climbing.
• Any tingle from an appliance, tap, gate or roof.
• An RCCB that has been “fixed” by someone and never trips any more. Press its TEST button. If it doesn’t trip, it needs replacing, and you should ask what was changed in the DB.

When rewiring work touches the DB, remember that wire colours are changing: under ST’s directive on new cable colours, new or upgraded wiring may use brown, black and grey phases with a blue neutral from 2026, mandatory from 2029. In a newer installation, black can be a phase, not a neutral, so don’t assume.