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How safe is your water heater? Here are 7 things to know to avoid deadly accidents

SINGAPORE: When Thakshnamurthy’s family moved into a seven-year-old resale flat in 2021, he did minor renovations but left the electrical system and water heater in place as everything looked “brand new”.

Then last November, fire broke out in the bathroom when his son was showering. His wife immediately went out to switch off the electricity at the mains while he got everyone else to leave the flat. No one was hurt.

The fire was due to improper installation of the connecting wires between the water heater and the circuit breaker, which eventually melted the wire insulation.

After that, Thakshnamurthy spent more than S$2,000 getting a licensed electrician to rewire his entire home and install a new water heater.

“It was very scary,” he told Talking Point as he showed programme host Steven Chia photos of the charred bathroom.

To be registered and sold in Singapore, all water heaters — as controlled goods — must have the mark. “Those without (the) safety mark aren’t allowed to be installed,” he warned.


Since 1985, all new homes must have a residual current circuit breaker (RCCB) installed. This device can cut off the power supply when it detects a leakage of electricity from an appliance or from wiring.

It is estimated — from a sample survey of about 1,800 HDB flats built before 1985 — that fewer than one per cent of such flats do not have an RCCB protecting the entire unit.

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But the mere presence of the RCCB does not necessarily mean a water heater is safe to use. For example, the RCCB could be faulty or improperly installed.

“Test (to see) if the RCCB is working, then … test (to see) if the heater’s circuit is linked to this RCCB,” Peck advised.

Customers can verify a licence on the EMA website, as with a plumber’s licence by using national water agency PUB’s search tool.

The installation of storage water heaters, for instance, must be carried out or supervised by a licensed plumber, who must submit a pre-installation plan to the PUB for approval.

This paperwork is the reason plumber Steven Tang charges about 10 per cent more than his unlicensed counterparts.

Teo, meanwhile, may charge double the amount quoted by unlicensed electricians for the same job, depending on how the water heater was wired previously. “We have a lot of things to check,” he said.

With normal usage, it typically takes a few years before overheating occurs, he added. But just a leakage of around 0.1 ampere — sufficient to light a bulb — passing through a human body can be deadly.

“It’s enough to kill one person,” he said. “The problem is, while you’re using a water heater, you’re wet. … Water is a good conductor of electricity.”

As Peck stated: “For instant heaters, the only contact point is (between) your hand and the heater, so there’s no other way for the current to flow in any direction other than your hand.”

Between 2014 and 2021, all five electrocution deaths in HDB flats were linked to water heaters.

Users should connect their water heaters to a double-pole switch instead, Wang advised. “This (switch) can take currents of up to 20 amperes, which is enough for a water heater.”


Both types of water heaters can be a fire risk owing to their high electric current draw, which is about 3,000 watts, or 25 amperes, Peck said. In 2021, there were 17 cases of fires involving water heaters in homes.

When Chia had his storage heater checked, Peck found that the wires connected to it were too thin. Instead of measuring 2.5 millimetres square, the existing wires were 1.5 mm thick.

“When the current is high, (the wires) will overheat and will start to burn,” said Peck, who considered it a “fire hazard”.

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On a day-to-day basis, users — especially those who have a storage heater — should switch on their heater 10 minutes before use, advised Peck. After use, they should switch it off to save electricity.

He also advised having heaters checked by someone qualified once every three years.

And now that Chia can do his own basic checks, he plans to “take a sniff around”. He said: “If you smell burning plastic, it might mean the wiring is overheating. And that’s not good.”

Watch this episode of Talking Point here. The programme airs on Channel 5 every Thursday at 9.30pm.

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