Water heater 3 pin plug: what the rules say
In a written answer to Parliament in 2018, MND said that water heaters should be connected to a 20 ampere socket switch, and not to a normal 3-pin socket that supports 13 amperes. It added that water heaters must be installed by an electrical worker licensed by the Energy Market Authority (EMA).
CPSO's safety tips on electric water heaters give similar guidance. Hire a Licensed Electrical Worker (LEW) to make sure the heater is properly wired. A water heater should not be connected to a 3-pin socket outlet; it should be wired directly to the mains through a double pole switch. Do not use extension cords or multi-way outlets to power it.
If your heater runs from a water heater plug socket today, do not change the plug or add an adaptor yourself. Ask a Licensed Electrician to change the connection.
Double pole switches and dedicated points
A water heater double pole switch is the connection CPSO describes, and CPSO also covers the heater itself. Instantaneous and storage electric water heaters are Controlled Goods and must carry the SAFETY Mark before they can be sold in Singapore. A storage water heater should have a pressure relief valve. Do not modify or repair the heater yourself, and switch it off when not in use.
Under HDB's guidelines for electrical works, in flats with a 30amps main switch an individual instantaneous water heater should not exceed 3kW, and a storage water heater 1.5kW. Not sure which main switch your flat has? Ask your Licensed Electrician. HDB also says power points should not be installed within bathrooms or toilets, which are wet areas under the Singapore Standard SS 638 code of practice. New wiring cannot be embedded in walls or plaster; it runs in surface trunking, above a false ceiling or behind carpentry.
Warning signs
EMA's electrical safety advice says overloading power points may lead to overheating and start a fire, so do not piggy-back several plugs into one socket with double adaptors. Replace cords with broken or frayed insulation instead of joining them with insulation tape. Keep electrical appliances away from water, and do not touch an open outlet or switch with wet hands.
For the heater itself, CPSO says not to use a water heater that appears damaged or is leaking. Our post on water heater warning signs covers more things to look out for.
If the heater keeps tripping the power, keep it off and have a Licensed Electrician check it. Our guide to water heater tripping explains more.
Getting an LEW to fix it
Replacing a plug socket with a proper connection is work EMA lists for Licensed Electrical Workers, which includes adding, extending or replacing power points such as socket-outlets and switches. EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. Check the licence card before work starts, or search for the worker on EMA's ELISE portal.
New wiring, rewiring and extensions have to be tested by an authorised officer from SP Services before supply can be turned on, EMA's safety page notes. You can compare licensed electricians before you ask for quotes.
FROM THE HOMEZYPRO DIRECTORY
Published water heater point rates
For the most common unit (per job), the lowest published water heater point rates from 6 companies run from S$60 to S$180 per job (middle rate S$120), for one water heater point or connection. The middle figure is a real published rate, not an average. Each figure is one company's own advertised rate with its conditions, not a quote.
See 7 published water heater point rates and sources
| Company | Service as listed | Rate | Source |
|---|---|---|---|
| Mr Electrician Pte Ltd | Connect Water Heater | S$50 | mrelectrician.sg |
| Repair.sg | Water heater installation | From S$60 per job | repair.sg |
| Skyteam Electrical Pte Ltd | Instant Water Heaters (storage-less) | S$60 per job | skyteamelectrical.sg |
| Sparkflow Pte Ltd | Water heater installation | From S$120 per job | sparkflow.com.sg |
| Yong Jin Solutions Engineering Pte Ltd | Water heater point (with isolator & MCB) | From S$120 to S$200 per job | yongjinelectrical.sg |
| 81 Electrical | Water heater isolator (20A) | From S$160 per job | 81electrical.com |
| Alpha & Omega Trinity Pte Ltd | Water Heater | From S$180 per job | aotrinitysg.com |
7 companies publish a water heater point line. 6 price it per job: S$60 to S$180 per job, with S$120 in the middle. Both middle companies print S$120, so it is a real published rate as printed. One line, S$50, is printed without a unit. The scope as printed is one water heater point or connection. Rates for other jobs are on our electrical costs page.
The plumbing side
PUB says regulated water service and sanitary plumbing works must be done by PUB Licensed Plumbers, except the simple plumbing works handymen may do. On the water service side, that list includes replacing or removing any pipe between a stop valve and an instantaneous water heater. Pipework for a storage water heater is not on the list, so it is PUB Licensed Plumber work.
If you are replacing the heater too, compare water heater services and try the water heater size calculator before you choose a new unit.
NEXT STEP
See electrical companies in the directory with their published prices, the areas they say they cover and their sources.
Compare electriciansWhen to stop and call a professional
Stop using the heater if it trips, leaks or the plug is hot. Call a Licensed Electrician for the wiring, and a licensed plumber for the pipework.
When you ask for quotes, check what each one covers:
- A double pole switch or 20A point for the heater.
- Whether the job uses a 20A double pole switch, and whether it is part of the price; in HDB flats a 20A isolator is allowed only for aircon installation (HDB).
- Testing of the new wiring by SP Services.
- Removal of the old plug socket.
- Whether the job needs an HDB permit, if you live in an HDB flat.
Our water heater installation steps guide explains the rest of a new installation.
Questions
Can I plug my water heater into a normal socket?
No. MND says water heaters should be connected to a 20 ampere socket switch, not a normal 3-pin socket that supports 13 amperes. CPSO says a water heater should be wired directly to the mains through a double pole switch. If yours runs from a plug today, ask a Licensed Electrician to change the connection.
What switch should a water heater use?
Can I use an extension cord for a water heater?
Who can rewire my water heater?
A Licensed Electrical Worker (LEW). EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. Check the worker's licence card before work starts, or search for them on EMA's ELISE portal. New wiring is then tested by SP Services before supply is turned on.
How much does it cost to install a water heater point?
7 companies publish a water heater point line, and 6 price it per job: S$60 to S$180 per job, with S$120 in the middle. These are published rates as printed, and one line is printed without a unit. Lines mix connecting a heater and installing a new point, so ask what each price includes.
Is a 3-pin plug safe for an instant heater?
No. The CPSO safety tips cover both instantaneous and storage electric water heaters, and say a water heater should not be connected to a 3-pin socket outlet but wired directly to the mains through a double pole switch. In flats with a 30amps main switch, HDB says an individual instantaneous water heater should not exceed 3kW.
Prices come only from the sourced company rates in the HomezyPro directory, shown with each company and its source.
Practical guidance for planning a home job in Singapore. Company prices come from the HomezyPro directory, each linked to its source; rules and safety points link to the agency or manufacturer that sets them. This is not a site inspection, a quote or professional advice for your home.
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