What electrical checks should you do on a resale flat?

Resale flat electrical check: what you can and cannot do

As a buyer or new owner, you can look: check the DB box, sockets, plugs, cords and any trunking for cracks, scorch marks or heat, and press the RCCB test button once with dry hands. Do this at a viewing with the seller's agreement, and again after you get the keys.

Opening a cover, testing circuits or changing anything is work for a Licensed Electrical Worker (LEW), so note what you see for the electrician. For leaks, windows and doors, use the general resale flat inspection checklist.

DB box age and breakers

HDB explains that the consumer unit, or DB box, holds the main switch, miniature circuit breakers (MCBs) and an RCCB. An MCB trips to cut supply to its circuit on an overload or short circuit. The RCCB cuts off electricity in the flat when it detects an earth current leakage.

To test the RCCB, switch off sensitive equipment such as computers, then press its test button, labelled T, once with dry hands. HDB says it should switch off; reset it afterwards. If it does not, it may be defective, and HDB advises engaging a Licensed Electrician to replace it.

The Energy Market Authority (EMA) says all residential premises must have an RCCB or earth leakage circuit breaker (ELCB) rated at no more than 30mA. HDB flats built before 1985 did not come with one unless the owner installed it later. EMA says to look for a switch with a "Test" button. See how to read a DB box.

Replacing or upgrading the whole board is also LEW work, so ask the seller whether it has been changed. 5 companies publish a DB box replacement line; 4 price it per job, from S$280 to S$320 per job, as printed.

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Published DB box replacement rates

For the most common unit (per job), the lowest published DB box replacement rates from 4 companies run from S$280 to S$320 per job, to replace or upgrade the DB box. Each figure is one company's own advertised rate with its conditions, not a quote.

See 5 published DB box replacement rates and sources

Lowest matching advertised rate per company, in SGD as published. "From" marks a starting price and ranges are shown in full. Check the source for minimums, GST and inclusions.

Company	Service as listed	Rate	Source
SC Electrician	Main Distribution Board (DB Box) Replacement	S$280 to S$480 per job	scelectrician.sg
Electrician24 Singapore	DB Box Upgrade	S$300 to S$600 per job	electrician24.sg
Lito Electrical Service	DB box replacement 2 ROOM	From S$320 per job	litoelectrical.com
Repair.sg	Distribution board supply and install	From S$320 per job	repair.sg
Mr Electrician Pte Ltd	MCB & DB Box SP 40A 18P	S$450	mrelectrician.sg

Socket and wiring condition

Look at every socket, switch and plug. HDB lists the causes: overheated plugs or frequently blown plug fuses come from loose connections, overloaded circuits or broken cables, and burnt marks at a socket come from a plug not fully inserted or an overloaded circuit. A 13A plug should have a 13A fuse, and only a Licensed Electrician can replace socket outlets.

EMA says not to use cracked or broken power points or extension sockets, and to have damaged ones replaced by an LEW. Overloading power points may lead to overheating and start a fire, so do not piggy-back plugs into one socket with double adaptors. Replace cords with broken or frayed insulation instead of taping them.

Sockets show only part of the picture: with old wiring in an HDB flat, cable age matters too. If you notice a burning smell from a socket, do not use it until a Licensed Electrician has checked it.

When to budget for rewiring

HDB gives the estimated average lifespan of a PVC electrical cable as about 25 years, and advises replacing wiring when its lifespan is over or it has deteriorated. An LEW can check the wiring and advise whether it needs replacing. Ask the seller how old it is and whether there is paperwork from any earlier rewiring.

HDB's guidelines for electrical works say rewiring needs no HDB permit, but embedding wiring in reinforced concrete slabs, beams, columns, walls, wall plaster or other finishes is not allowed. The appointed LEW submits SP Services Form CS/5H, endorsed by HDB, and applies for testing of the completed works.

HDB says resale completion is about 8 weeks after HDB accepts the resale application. You get the keys at completion, so the LEW visit and any resale HDB rewiring usually come after that.

5 companies publish a whole-home rewiring line, all per job, from S$1,500 to S$2,800 per job, with S$1,890 in the middle: the middle company's own published rate, not an average. Each is that company's lowest package as printed, usually for its smallest flat type.

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Published whole-home rewiring rates

For the most common unit (per job), the lowest published whole-home rewiring rates from 5 companies run from S$1,500 to S$2,800 per job (middle rate S$1,890), for a whole flat or house; each company's lowest package, usually its smallest flat type. The middle figure is a real published rate, not an average.

See 5 published whole-home rewiring rates and sources

Lowest matching rate per company, in SGD as published.

Company	Service as listed	Rate	Source
Electrician24 Singapore	Full House Rewiring	From S$1,500 per job	electrician24.sg
SC Electrician	3-Room HDB Full Rewiring	S$1,800 to S$2,500 per job	scelectrician.sg
Bestvolt Contractors Pte. Ltd.	HDB Rewiring Price Singapore | Packages	From S$1,890 per job	bestvoltcontractors.com
Trizone Electrical & Aircon Pte. Ltd.	Full HDB Rewiring (3-Room)	From S$2,500 per job	trizoneelectricals.com
Active Power Electrical Engineering Pte. Ltd	Our HDB Electrical Rewiring Cost (Singapore)	S$2,800 per job	activepowerelectrical.com

For more on prices, see HDB rewiring cost.

The full checklist

Use this list at a viewing and again after you get the keys. If the wiring needs replacing, compare companies that offer rewiring.

• Find the DB box and look at it without opening the cover.
• Check that there is an RCCB at all: a switch with a Test button.
• Switch off computers, then press the RCCB test button once with dry hands and reset it.
• Note any breaker that trips, or an RCCB that does not switch off.
• Look for scorch marks at sockets and plugs that feel warm.
• Check that 13A plugs have 13A fuses.
• Look for cracked sockets, piggy-backed adaptors and frayed cords.
• Ask the seller how old the wiring is and whether there is rewiring paperwork.
• Book an LEW for anything more.

Who to call

EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. Every LEW carries a licence card with a photograph and licence number, and EMA's guide to engaging licensed workers says to verify it before work starts. You can also search EMA's ELISE portal.

See what work needs an LEW, browse electrical companies or compare electrician costs by job.

Questions