Electrical questions answered

Electrician FAQ: power trips and safety

What should I do when the power trips?

Start with the safety check above. Then, as practical guidance rather than an official rule, switch off or unplug what was running and push the tripped switch back up once. If it trips again straight away, leave it off and call a Licensed Electrician. The power trip help page goes into more detail.

How often should I test the RCCB?

Once a month, says the Energy Market Authority (EMA). The RCCB is usually in the DB box, a switch with a "Test" button. HDB suggests switching off sensitive equipment such as computers first. Pressing the button should switch the RCCB off; reset it afterwards. If it does not switch off, it may be defective.

Is it safe to use a double adaptor?

Not for running several plugs from one socket. EMA says not to "piggy-back" multiple plugs into one socket with double adaptors, because overloading power points may lead to over-heating and start a fire. Stop using cracked or broken power points and extension sockets, and have an LEW replace them. The power strip overload guide has more.

Licensed electrical workers

Electrical work at home should be carried out or supervised by a Licensed Electrical Worker. The class of LEW depends on the scale of the installation, with Licensed Electrical Technicians and Licensed Electrical Engineers covering larger installations, as EMA's page on engaging LEWs sets out.

Who may do electrical work in an HDB flat?

A Licensed Electrician. EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. EMA's list of LEW work includes wiring, adding or replacing sockets, switches and lighting points, and repairing or replacing circuit breakers. See what work needs an LEW for more.

How do I check an electrician's licence?

Ask to see the licence card before any electrical work starts. EMA says every LEW carries one with a photograph, name, identity card number and licence number. You can also search EMA's ELISE portal or call 6835 8075, as its electrical safety page notes. The licensed electricians page explains more.

Wiring and renovation

Can new wiring be hidden in my HDB walls?

No. HDB's electrical works guidelines do not allow wiring to be embedded in reinforced concrete slabs, beams, columns, walls, wall plaster or other finishes, even in metal or high impact PVC conduit. New wiring runs in surface trunking, above a false ceiling or behind carpentry. The guide to electrical renovation rules in HDB flats covers the rest.

How long does home wiring last?

About 25 years on average for PVC cables, says HDB. HDB advises replacing wiring when its lifespan is over or it has deteriorated, and an LEW can check it. Overheated plugs or frequently blown plug fuses can come from loose connections, overloaded circuits or broken cables. Price depends on the job; see the HDB rewiring cost guide.

Costs and installs

Where can I see what electricians charge?

On the electrician costs by job page and the electrician cost estimator, which both show the rates companies publish per job. Price depends on the job, so ask each company what its quote includes before work starts, for example whether trunking, materials and arranging the SP Services testing are covered.

Does a new socket need an HDB permit?

Not for an additional 13A power point. HDB says these need no permit, but the wiring must not be embedded and an SP Services Form CS/5H endorsed by HDB must be submitted for testing. A new 15A power point or 20A isolator needs a permit in flats with a 30A main switch. On cost, see power point installation cost.

Where to go next

If your electrical questions are about a specific job or a fault at home, these pages go further. Before you book, check the electrician's licence card and ask what the quote includes. For anything involving water near electrics, keep away and call a Licensed Electrician.

• Electrical companies: browse companies in the directory with the prices they publish.
• Electrician guide: plan an electrical job before you contact anyone.
• Home electrical safety checklist: routine checks you can do around your home.
• No power in the whole flat: when every circuit is off at once.

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