HDB Electrical Works: Permits, Rewiring Rules and LEW Checks Before You Renovate

Most renovations touch the electrics: an extra power point behind the TV console, more lighting points for a cove ceiling, a new oven, or a full rewire in an older resale flat. In an HDB flat, electrical work follows HDB's own guidelines, and a few of them decide what is possible before your designer draws anything.

This guide sums up what HDB says about electrical works in HDB flats. It is general information, so check the latest rules for your own flat with HDB before you start.

Who can do the work

According to HDB's renovation guidelines for electrical works, all wiring installation work must be carried out by an Energy Market Authority (EMA) licensed electrical worker (LEW). HDB also says the flat owner must supervise the electrical work and make sure it is installed by an EMA licensed contractor, and that any air-conditioning unit is installed by an installer trained by the Building and Construction Authority (BCA).

Your main switch rating decides a lot

HDB explains that blocks completed on or after 1 January 1994, and blocks that have gone through the Main Upgrading Programme (MUP) or Home Improvement Programme (HIP), are provided with higher electrical loading of a 40amps main switch. Older flats without this may have a 30amps main switch. If you are unsure, HDB says you can check the electrical loading of your block.

This matters because:

• Permits for higher-capacity points: flats without higher electrical loading need an HDB permit to install new 15amps power points for air-conditioners or other higher-capacity appliances. Flats with higher loading do not need this permit.

• Appliance limits on 30amps flats: HDB caps each instantaneous water heater, washing machine with heater, electric oven and cooker unit at 3kW, and a storage water heater at 1.5kW.

• Everything shares one main switch: HDB sets no limit on the number of appliances or extra points, but they remain subject to the rating of your existing main switch.

If your block is due for HIP, our HDB HIP timing guide explains what to time around it.

What you can add without an HDB permit

HDB lists several electrical works that do not need a permit, though they still have to follow HDB's guidelines and conditions:

• More points: additional lighting points, fan points and 13amps power points, plus extension of wiring or rewiring

• Trunking and conduit: covering wiring with PVC trunking, or encasing surface wiring in metal or high impact PVC conduit

• Switchboard items: altering or adding an RCCB, ELCB, MCB, socket outlet or main switch

• Ceiling fans: the fan should not exceed 6kg, with at least 2.4m clear height from the finished floor to the fan blades

• Exhaust fans: allowed only in bathrooms, not in the kitchen, service yard, balcony or bedrooms

Anything not listed in HDB's guidelines, or with technical details that differ from them, needs HDB's approval before work starts. For non-electrical works, our HDB renovation permit guide explains what needs approval.

Wiring rules that shape your design

A few of HDB's technical conditions affect where points can go and how wiring is run:

• No embedding in the structure: wiring housed in metal or high impact PVC conduit must not be embedded in reinforced concrete slabs, beams, columns or walls, or in wall plaster or other finishes. In practice, new wiring runs on the surface in trunking or conduit, or behind carpentry and false ceilings.

• Drilling limits: power-driven nails and screws must not exceed 6mm in diameter or 40mm in penetration depth. In flats with concealed wiring originally provided by HDB, anchors must be kept away from the concealed conduits.

• No power points in bathrooms: HDB notes that bathrooms and toilets are wet areas under Singapore Standard SS 638, so power points should not be installed inside them.

• TV points: the original TV points must be left accessible, and any alteration or extension is to be done by a licensed StarHub Cable Vision installer.

This is why wiring is best planned before carpentry and the false ceiling are fixed. Our smart-home wiring guide and HDB lighting plan guide cover how to map points and lighting room by room.

When to consider rewiring

HDB estimates the average lifespan of PVC electrical cables at about 25 years and advises replacing the wiring when its lifespan is over or its condition has deteriorated. A licensed electrical worker can advise on the condition of your flat's wiring and whether it needs replacing. This is worth checking early if you have bought an older resale flat.

Testing, timelines and working hours

• SP Services testing: for new wiring or extension work, the SP Services Form CS/5H endorsed by HDB must be submitted to SP Services for testing. When the work is done, you apply to SP Services for inspection through your LEW.

• Permit timelines: where a permit is issued, HDB says approved electrical work must be completed within 3 months of the permit date for newly completed blocks, and within 1 month for existing blocks.

• Working hours: no work before 8am or after 6pm, and noisy work only on weekdays from 9am to 5pm, never on weekends or public holidays. Our HDB renovation hours guide covers the full rules and neighbour notices.

• Unauthorised work: HDB may require you to remove unauthorised work and reinstate your flat, including work done without a required permit or not done to its guidelines.

A simple electrical checklist for your renovation

• Check your main switch: confirm whether your flat has a 30amps or 40amps main switch before choosing appliances

• List your appliances: note ovens, induction hobs, water heaters and aircon units, and check them against your flat's limits

• Confirm the LEW: ask who the EMA licensed electrical worker is and that they will handle SP Services testing

• Plan the routes: agree where trunking, conduit and concealed runs behind carpentry will go, since wiring cannot be embedded in the structure

• Keep bathrooms point-free: plan bathroom appliances such as heaters around HDB's rules, with no power points inside

• Test at the end: switch on every point and light, and use our renovation handover checklist before your final payment

Where Blackwoods Interior stands

• Blackwoods Interior Pte. Ltd. (trading as Blackwoods Interior), UEN 201909521M

• CaseTrust accredited for Renovation Businesses (the standard tier, not Gold), valid through 28 April 2028

• Listed on HDB's Directory of Renovation Contractors (DRC)

Talk to Blackwoods Interior

Planning a renovation with new power points or rewiring? Book a free 30-minute consultation: WhatsApp us at 8754 3212 (Mon-Sat, about 10:00-19:00 SGT) or email Hello@bwi.sg. Visit www.bwi.sg to see more.

Cover image: illustrative concept, not a completed Blackwoods project. This guide is general information based on HDB's renovation guidelines for electrical works, checked on 26 October 2026. Rules can change, so check the latest requirements for your flat with HDB, and have a licensed electrical worker check your wiring, before you start any electrical works.