HDB DB Box Replacement Cost (2026): MCB, RCCB and Full Board

An HDB DB box usually holds a main switch, a residual current circuit breaker (RCCB), and one miniature circuit breaker (MCB) per circuit.

HDB's home care guide calls it a consumer unit. Each part has its own job:

• The main switch caps the current the whole flat can draw: HDB says 40A in blocks completed from 1 Jan 1994 or upgraded under the Main Upgrading Programme or Home Improvement Programme, and 30A in others.
• Each MCB protects one circuit, such as the lights, sockets, aircon or water heater, and trips on overload or a short circuit.
• The RCCB trips on earth leakage: current escaping to earth, often through damaged insulation or a faulty appliance.

Older flats can differ. EMA and HDB say RCCBs have been required in new installations since July 1985, and earlier homes were given fuses. So an unrenovated older flat may still have rewireable fuses or an older ELCB instead.

The electricity meter sits outside your flat, and the DB box inside it. Everything from the DB box into the flat is generally the owner's to maintain.

Replace one part when one breaker is faulty; replace the whole board when damage, age or missing protection affects several parts.

Diagnose before you replace. A breaker that keeps tripping is usually doing its job: the fault is often an appliance or a damaged circuit, and a new breaker would trip too. Power trip diagnosis costs from $80, and a separate guide explains why power keeps tripping.

What usually fails first is a loose terminal on a heavy-load circuit, such as the water heater, aircon or oven, which heats up and scorches the breaker.

Age alone isn't a reason to replace a board. But HDB puts PVC cable life at about 25 years, so an older flat's original board and wiring are worth an inspection. A separate guide covers whether your resale HDB flat needs rewiring.

The number of circuits, the type and brand of breakers, and the state of the wiring behind the board set the final price.

• Number of circuits: more circuits need a bigger board and more breakers.
• RCBOs instead of one RCCB plus MCBs: each costs more, but a leak cuts only its own circuit.
• Brand and enclosure: premium breakers, or a new box to fit the wall recess.
• Wiring behind the board: loose, undersized or heat-damaged cables found on opening need rectifying.

Flat size matters less than the number of circuits. Ask whether the quote includes the new breakers and enclosure, and which brand. Rewiring circuits, adding circuits and moving the board are separate jobs, each priced separately. If the wiring itself is past its life, a separate guide covers HDB rewiring cost.

A single breaker swap typically takes under an hour. A like-for-like full board usually takes 2 to 4 hours with the whole flat's power off, so plan for no fridge, Wi-Fi or aircon.

Only a licensed electrical worker (LEW) may replace a DB box or any breaker in it; HDB needs no permit for this work.

Under section 82 of the Electricity Act, no one may carry out electrical work unless they are an LEW or supervised by one. The Act says it is not unlawful to replace a lamp or a household-type fuse in your own installation, and EMA says rewiring, repair and replacement works must be done by a licensed electrical worker. An owner must not knowingly engage an unlicensed person; that is also an offence.

HDB's electrical works guidelines list altering or adding an RCCB, ELCB, MCB, socket outlet or main switch as work that needs no permit, subject to HDB's guidelines. A permit is needed for a new 15A point or a 20A isolator in a flat without higher electrical loading. For new circuits or rewiring, your LEW submits HDB-endorsed Form CS/5H to SP Services (part of SP Group) for testing. Work outside HDB's guidelines, such as moving the board, should be checked with HDB first.

When comparing quotes, ask who the LEW is and whether SP Services testing is covered.

Not for a replacement: EMA says repairing or replacing an RCCB isn't eligible for HDB's subsidised installation (EMA on Ask Gov).

HDB's RCCB Installation Assistance Programme was for sold flats completed in or before 1985 with no RCCB. If your flat has neither an RCCB nor an ELCB, call the HDB Branch Service Line on 6225 5432 before paying for a new board. The Energy Market Authority (EMA) says homes with neither can be fined up to $5,000 from 1 Jul 2025 (EMA on Ask Gov: RCCB requirement). A faulty RCCB isn't penalised, but an LEW should replace it. A separate guide covers whether an RCCB is compulsory in Singapore.

You can test the RCCB, reset a breaker once and take photos; changing any breaker or the board is licensed work.

Two shortcuts are common and dangerous. Fitting a bigger MCB to stop trips leaves the cable unprotected, so it can overheat. Bypassing an RCCB that keeps tripping removes your protection against electric shock.