Short answer: HDB estimates that PVC electrical cables last about 25 years on average and advises replacing wiring when it reaches that age or has deteriorated. All wiring work must be done by an EMA licensed electrical worker (LEW), new wiring must not be embedded in concrete or plaster, and the completed work must be tested through SP Services (SPSL) before use. Indicative costs start from a few thousand dollars, depending on scope.

Does your resale flat need rewiring?

Start with age. HDB states that wiring in a flat has a limited lifespan, estimated at an average of 25 years for PVC cables. If your flat is older than that and the wiring has never been replaced, it is worth having it checked before you renovate, not after.

Then look for symptoms. HDB's home care guide lists these warning signs and their likely causes:

  • Overheated plugs or frequently blown plug fuses: loose connections, overloaded circuits or broken cables.
  • Burnt marks at socket outlets: plugs not fully inserted or overloaded circuits.
  • Breakers that trip often: Miniature Circuit Breakers (MCBs) trip on overload or short circuit, and the RCCB trips when it detects current leaking to earth.

HDB's advice is that an LEW can check the condition of your wiring and tell you whether it needs replacing. That inspection is the right first step: some flats need a full rewire, others only need specific circuits, points or the distribution board replaced.

The rules for electrical works in HDB flats

HDB's electrical works guidelines set out these conditions:

  • Licensed worker only. All wiring installation work must be carried out by an EMA licensed electrical worker. You, as the owner, must supervise the work and make sure it follows HDB's guidelines.
  • No embedding in the structure. Wiring, including wiring 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.
  • Testing before use. You submit SPSL Form CS/5H, endorsed by HDB, to SP Services for testing of new wiring or extensions, and your LEW applies to SPSL for inspection of the completed work.
  • Fixings. Power-driven nails and screws must not exceed 6mm in diameter and 40mm in penetration depth. In flats with HDB's original concealed wiring, keep drilling away from the conduits shown in the layout plans.
  • No power points inside bathrooms. HDB notes these are classified as wet areas under the electrical installation code SS 638.
  • RCCB. The Ministry of Trade and Industry has stated that since 1985, all new homes and homes undergoing rewiring, including HDB flats, must install an RCCB.

Do you need an HDB permit?

It depends on your flat's electrical loading. HDB says blocks completed on or after 1 January 1994, or upgraded under the Main Upgrading Programme or Home Improvement Programme, have a 40amp main switch. For these flats, rewiring and extra lighting, fan and 13amp power points do not need an HDB permit, though the conditions above still apply.

Flats without higher electrical loading (30amp main switch) need an HDB permit to install new 15amp power points for air-conditioners or other higher-capacity appliances. If you are unsure, HDB lets you check the electrical loading of your block.

Working hours

HDB's terms say no work before 8am or after 6pm, and noisy work only on weekdays between 9am and 5pm, never on weekends or public holidays.

Hiding the wiring when it cannot go into the walls

Because new wiring cannot be chased into concrete or plaster, it runs on the surface in PVC trunking or conduit. HDB lists both as acceptable. The design question is how to keep it tidy:

  • Plan the route along ceiling edges, corners and skirting lines.
  • Many homeowners hide conduit runs above a false ceiling, inside cove lighting or behind built-in carpentry. That is why rewiring is best planned together with your ceiling and carpentry, not as a separate job. See false ceilings and lighting.
  • Paint trunking to match the wall where it stays exposed.

How much does rewiring a resale HDB cost?

Published figures vary because "rewiring" covers anything from replacing a distribution board to redoing every circuit. These are indicative market estimates, not quotes:

  • SmartCalculator (July 2026): full rewiring with a new distribution board about $2,000 to $4,500 per job; individual electrical points about $45 to $90 each.
  • ShopBack (May 2026): the electrical and lighting line for a 4-room resale renovation about $5,500 to $9,500, and an extra $5,000 to $9,000 where flats older than 30 years need full conduit replacement.

The gap between these numbers is mostly scope: the number of points, lighting, the length of new conduit and whether old trunking needs removing. A clear electrical layout, drawn before you ask for quotes, is the best way to get prices you can compare. Our guide on resale HDB renovation cost shows where this fits in the wider budget.

Planning the electrical layout

Rewiring is the cheapest moment to get the layout right. Before the LEW starts:

  1. Place your furniture first. Bed, sofa, TV, desk and dining table positions decide where points go.
  2. Count real needs. Bedside charging, the study, the kitchen counter, the router and any wall-mounted TV.
  3. List high-load appliances. Air-conditioners, ovens, induction hobs, water heaters and washing machines. HDB sets limits by main switch rating; for example, in 30amp flats an instantaneous water heater, electric oven or cooker unit should not exceed 3kW.
  4. Plan lighting circuits with switches at the doors you actually use.
  5. Keep the distribution board accessible. Do not box it into carpentry without an opening.

Questions to ask your contractor

  • Who is the LEW, and will they apply to SP Services for testing?
  • Is the whole flat being rewired, or only some circuits?
  • Is a new distribution board and RCCB included?
  • How will new wiring be routed and concealed?
  • How many points of each type are included, and what does an extra point cost?

How JIAHOME helps

We plan your electrical layout as part of the design, so every point is placed for your furniture before anyone quotes. Our quotation lists each item without prices, so any contractor can price the same scope. Learn more on our services page.

Last updated 15 October 2026