Singapore Wire Colour Code: 3-Phase, Old vs New (SS 638)

Quick answer: in Singapore today the live wire is brown, the neutral wire is blue, and the earth wire is green-and-yellow — the colours set out in Singapore Standard SS 638, which follows the international IEC harmonised code. The catch: older homes may still use the legacy red-black-green scheme, and work completed during Singapore's 1 March 2009 to 28 February 2011 transition may use either code. Because blue and black have different meanings between the old and new three-phase codes, never identify a conductor by colour alone. This guide covers both codes side by side, the transition dates, the three-phase colours, why mixed-era wiring is dangerous, and when an inspection makes sense.

What are the current electrical wire colours in Singapore?

Singapore's current wiring colours follow the IEC harmonised colour code, adopted locally through the national wiring standard — today that is SS 638 (Code of Practice for Electrical Installations), which replaced the older CP 5. EMA allowed the new colours from 1 March 2009, followed by a two-year transition through 28 February 2011. The new colours became mandatory for new electrical installations from 1 March 2011.

For the standard single-phase 230V / 50Hz supply found in most Singapore homes:

• Live (L): Brown — carries current from the supply to the appliance. Touching it is dangerous.
• Neutral (N): Blue — the return path that completes the circuit.
• Earth (E): Green-and-yellow stripes — the protective conductor that carries fault current safely to ground so the RCCB or breaker can trip.

These are the colours expected in work carried out after the transition. Work completed during the 2009-2011 transition may use either the legacy or harmonised code, so the building's age alone cannot prove which colours are present. For a single project, the selected colour code should be applied consistently; where new work interfaces with legacy wiring, the Licensed Electrical Worker should identify and label the interface clearly.

What were Singapore's legacy wiring colours?

Installations completed before 1 March 2009 typically use the legacy colour code, inherited from the British system. Either code could be used during the official two-year transition:

• Live: Red
• Neutral: Black
• Earth: Green (plain green, or green-and-yellow in some later installations)

You will still find these colours in older HDB flats, walk-up apartments, condos, landed houses and shophouses that have never been fully rewired. Legacy colours alone do not make an existing installation defective; condition, protection and safe identification matter. New fixed-wiring work has had to use the harmonised colours since 1 March 2011, which is why some older homes contain a mix of both codes.

Old vs new wire colour codes: comparison table

The trap to remember: blue and black swapped meanings between the old and new codes. In the old code, black was neutral and blue was a live phase. In the new code, blue is neutral and black is a live phase. In a building with mixed-era wiring, colour alone cannot tell you whether a blue or black wire is safe to touch.

What are the three-phase wire colours in Singapore?

Most HDB flats run on single-phase 230V supply, but larger landed homes, homes with high electrical load (multiple aircon systems, EV chargers, electric hobs) and commercial units use three-phase 400V supply. Under the current code, the three phases are brown (L1), black (L2) and grey (L3), with a blue neutral and green-and-yellow earth. Under the old code, the phases were red, yellow and blue with a black neutral — which is exactly why old switchrooms are labelled "R-Y-B".

If you are upgrading from single-phase to three-phase supply — sometimes considered when adding multiple aircon systems or an EV charger — the new circuits must use the current colours. A Licensed Electrical Worker must assess the connected load, protection and existing distribution board capacity; a DB upgrade may be required, but it is not automatic.

Why do wire colours matter for safety?

Colour coding exists so that anyone opening a switch, socket or DB box can immediately tell which conductor is dangerous. Getting it wrong has real consequences:

• Reversed polarity: if live and neutral are swapped at a socket, an appliance can remain energised even when its switch is off, because the switch is interrupting the neutral instead of the live.
• Mixed-era confusion: in a pre-2009 flat that has had partial rewiring, a black wire might be old neutral or new live phase, and a blue wire might be new neutral or old phase. Electricians treat every conductor as live until proven otherwise with a voltage tester — homeowners should never trust colour alone.
• Broken earth path: if the earth conductor is misidentified or left disconnected, a fault inside a metal-bodied appliance (kettle, washing machine, water heater) can make the casing live without tripping anything.
• Tripping faults that hide: miswired circuits are a common root cause behind recurring power trips that seem random — the RCCB is doing its job, but the underlying wiring fault never gets found.

Do I need to rewire old red-black wiring?

Not because of the colours alone — existing legacy-colour installations were not automatically required to be replaced. What matters is the condition, protection and verified identification of the wiring. Ask a Licensed Electrical Worker to inspect it when you see any of these:

Common domestic installations may use 2.5mm² conductors for some socket circuits and 1.5mm² for some lighting circuits, but conductor size cannot be chosen from appliance type alone. Circuit design, protective-device rating, installation method, grouping, temperature and cable length all matter, so a Licensed Electrical Worker must verify suitability for the actual installation.

What does rewiring or electrical work cost in Singapore?

These are FixMove's 2026 reference ranges for the jobs most relevant to old wiring. Full breakdowns are on the electrician cost guide and the DB box upgrade cost page.

A S$10 fuel surcharge applies to every visit. No additional standard call-out or inspection fee applies. Urgent service or a customer-requested appointment time adds one S$30 fee, subject to technician availability and confirmation. The S$30 is a separate service fee. Pricing terms.

Whole-unit rewiring is quoted per job because it depends on the number of points, whether conduit is concealed or surface-run, and how much hacking and making-good is involved. For the full breakdown, see the electrician cost guide — or send a photo of your DB box and floor plan on WhatsApp for a written quote before anyone visits.

Can I do my own electrical wiring in Singapore? (DIY legal limits)

Singapore regulates electrical work tightly. Under the Electricity Act, administered by EMA, electrical wiring work must be carried out by, or under the supervision of, a Licensed Electrical Worker (LEW). In practice the line for homeowners is:

• Generally fine to DIY: replacing a light bulb, replacing the fuse in a plug top, plugging appliances in and out, resetting a tripped MCB or RCCB.
• Requires a licensed electrical worker: anything involving fixed wiring — adding or moving power points, extending circuits, replacing a DB box or its breakers, rewiring, and new circuits for aircon, water heaters or EV chargers.

Carrying out electrical work without the required licence may breach Singapore's electrical-safety requirements. Insurance coverage and any HDB approval or resale implications depend on the policy wording, the work scope and the records available, so verify those points with the insurer or relevant authority instead of assuming a fixed outcome. EMA maintains a public register of LEWs at ema.gov.sg — FixMove arranges works requiring an LEW through EMA-licensed personnel, and you can request the assigned worker's licence number before work starts.

Related Reading

• Electrician Cost Singapore — full 2026 price list for sockets, MCBs and rewiring
• Electrical Services Singapore — trips, sockets, lighting and wiring repairs
• Power Trip Electrician — why your RCCB keeps tripping and how it's traced
• DB Box Upgrade Cost — replacing old fuse boxes with MCB/RCCB units
• 24-Hour Electrician Singapore — for burning smells, sparking and total power loss
• FixMove Blog — all home-services guides

FAQ

Published: 11 June 2026 · Updated: 16 July 2026 · By FixMove Electrical Team — works requiring a Licensed Electrical Worker are arranged through EMA-licensed personnel. Sources: EMA Circular RD/E01/09, EMA cable-colour fact sheet, Singapore Standard SS 638.