Choosing an Electrical Contractor for a Landed Home in Singapore: 10 Questions

A landed house is the largest electrical installation most people will ever personally own — and the least supervised. No MCST, no building LEW, no managing agent checking anyone's work.

From the meter compartment at your gate to the last downlight in the attic, it is yours. Whoever you engage is the only professional judgment applied to the whole of it.

Which is why it isn't a handyman job scaled up. It's a design job — total load, cable sizing, protection grouping, earthing, lightning protection — then an installation job, then testing that proves the first two were done right.

So when three quotes come back at numbers that don't look like the same project, the useful question isn't "which is cheapest?" It's "which of these firms can actually carry a job of this class, and prove it?"

Why a landed home is a professional-grade electrical job

In an HDB flat or a condo unit, most of the installation isn't yours — the riser, the incoming supply, the building's earthing, the switchroom. Your side is small, standardised, and there is usually a second pair of eyes on any contractor who touches it.

A landed house has none of that, and it carries loads a flat never sees: several aircon zones, induction cooking, instant water heaters, a pool pump, sometimes a lift, solar with a battery, one or two EVs.

Stack enough of that and the house outgrows a single-phase supply entirely — which is why many landed homes end up on three-phase power, with a main switchboard rather than a consumer unit.

Then come the parts of the job a flat simply doesn't have.

When a low quote is fine — and when the saving comes out of your walls

Here is what makes landed different: the downside isn't bounded.

In a flat, a fault is one circuit and one afternoon. Behind a landed home's plastered walls, feature ceilings and finished landscaping, the fault is the cheap part — finding it is what costs.

Undersized cable feeding a wing of the house. An earth path that measures fine on a dry day. A garden circuit that trips only in heavy rain. None of it dramatic. All of it surfacing two years in.

The saving on a keen quote is a fixed, one-time number. The exposure is not.

That said, a low quote is not automatically a bad one. Some contractors are genuinely leaner — smaller office, no estimating department, fewer vehicles — and their cable is still copper, their LEW is still real, their testing still happens.

On a job you can still see and still bound, that is a fair trade. A whole landed installation is neither.

So past a certain price, ask where the saving is coming from. There are only four places it can come from:

• ›The licence — who is qualified, and answerable, for the design.
• ›The materials — chiefly the cable, the biggest hidden cost in the house.
• ›The testing and documentation — what proves it is safe, not merely working.
• ›The accountability — whether there is anyone to come back to.

The six things a landed job needs from a firm

Size isn't the test — structure is, and structure has a floor. Below a certain size these six aren't cheaper, they're absent:

• ›Design capability. Somebody works out your maximum demand, sizes cables against load and run length, grades the protective devices so a fault trips the nearest breaker and not the whole house, and designs the earthing. On a heavy house this is the difference between an installation with headroom and one already at its limit on handover day.
• ›A licensed worker settled in the firm — not a stranger engaged for the signature. The LEW who certifies your house should be the LEW who has seen it.
• ›Supervision, meaning somebody reviewing work they didn't do themselves — and enough crew to hold a programme when the ID, the aircon contractor and the plumber all want the same ceiling void in the same week.
• ›Coordination. The electrical scope collides with everything: reflected ceiling plans, aircon condensate and refrigerant runs, plumbing chases, the pool, the gate, the lift. A firm that has done this before sequences it; one that hasn't discovers it.
• ›Documentation as a habit, not a favour — produced because that's how the company works, not because you had to ask.
• ›Longevity and cover. Insurance, a stated defect liability period, and a company likely to still exist when that period is being tested. This is the one you cannot verify at handover and the one that matters most later.

The licence isn't paperwork — it's who is legally answerable

An LEW licence is a personal government licence, not a trade certificate or a “certified electrician” badge. One named individual puts their own name on your installation and carries the consequences. Formally: electrical installation work must be carried out by, or under the supervision of, a Licensed Electrical Worker licensed by the Energy Market Authority.

That matters in three practical ways, none of them administrative:

• ›Design judgment, not just installation. Cable sizes, device ratings, how load is spread across circuits and phases, the earthing arrangement — all decided before anyone pulls a wire, and precisely what a licence is for.
• ›Sign-off you will need later. LEW testing and certification is what the utility looks for before supply is turned on, what your insurer will ask about after an incident, and what a buyer's lawyer will ask for when you sell.
• ›Legal exposure that isn't only the contractor's. Doing electrical work without the required licence is an offence under the Electricity Act — and it is also an offence for an owner or occupier to knowingly engage someone who isn't permitted to carry it out. "Knowingly" is doing real work in that sentence, and the way you stay on the right side of it is to ask for the licence and check it.

The cable in your walls: what "cheaper wire" actually means

Cable is the largest material line in a house rewire — and the easiest thing in the job to substitute, because within a week it is buried in a wall and nobody audits it again.

Two substitutions are worth guarding against. One of them is illegal.

Copper-clad aluminium (CCA) is an aluminium conductor with a thin copper coating, so the cut end and the terminal look like copper. That is the point of it.

It is also prohibited. The Electricity (Electrical Installations) Regulations bar cable with aluminium conductors in any installation used, wholly or partly, for domestic purposes — and a copper-clad conductor is an aluminium conductor under a copper skin. Not a grey area, and the prohibition binds whoever uses it, not only whoever sold it.

Why it matters physically: aluminium creeps under a screw terminal and moves more with temperature than copper. Connections gradually loosen. A loose connection carrying real current becomes a hot joint — and hot joints inside walls and boards are how electrical fires start.

Undersizing is the quieter one. 2.5 mm² where the design calls for 4 mm² — identical to look at, cheaper per metre, and it works right up to the afternoon the circuit is finally loaded to what it was designed for. Sizing is a calculation under SS 638, not a matter of habit.

Ten questions to ask every contractor you meet

Ask all ten, of everyone, and compare how fast the answers come. Questions 3, 6 and 10 are the ones a lone operator genuinely cannot answer, however skilled they are.

The landed-only scope: outdoors, earthing and lightning

Three parts of a landed installation have no equivalent in a flat, and all three are where a cheap quote goes quiet.

• ›Outdoor circuits. Landscape lighting, the gate and intercom, the pool, the car porch — permanently exposed to sun, salt air and monsoon rain. They need properly rated weatherproof enclosures and glands, cable suited to the route, and residual current protection sized for the job. Done cheaply, these are the circuits that start nuisance-tripping in the second wet season, and the reason is almost always water in an enclosure that was never rated for it.
• ›Earthing. On older houses the earth path is frequently the weak link — an earth-loop impedance too high to clear a fault quickly enough. It is invisible, it makes no noise, and every other protective device depends on it. A new earth pit and bonding is a normal, honest line item, and the proof it works is a measured electrode resistance, not an assurance.
• ›Lightning protection — not optional on a new build. Under the Building Control Regulations a building must be protected against lightning, and unlike headroom, natural lighting or ventilation there is no exemption for a house built for the owner's own use — BCA's own exemptions table records it as "no exemption, compliance required". The accepted solution is a system designed and installed to SS 555 to a minimum of Class III. A risk assessment decides whether your house needs a higher class than that floor, not whether you need a system at all.

The six tests your installation must pass before handover

The difference between an installation that works and one that is safe is measurement. "It works" only means the lights come on. It says nothing about whether a fault would be cleared fast enough to stop someone being hurt — and on a house full of outdoor circuits, long runs and heavy loads, that is the entire question. A proper commissioning covers, at minimum:

• ›Earthing and bonding continuity — the protective path is genuinely connected end to end, not just terminated at both ends.
• ›Insulation resistance — the insulation between live conductors, and between live conductors and earth, is intact and hasn't been nicked by a screw, a nail or a careless pull.
• ›Earth-loop impedance — the fault path is low enough that the breaker trips quickly when it has to. Long landed runs and older earthing arrangements are exactly where this quietly fails.
• ›Earth electrode resistance — the new earth pit actually achieves the resistance it was designed for, measured rather than assumed.
• ›RCD trip testing — the life-saving device trips within its rated time. The button on the front proves the mechanism moves; it does not measure the threshold or the time.
• ›Polarity, correct connection and phase sequence — live and neutral where they belong at every point, and on a three-phase board the phases in the right rotation, which matters to every motor in the house: the pool pump, the lift, the aircon compressors.

Your handover pack: four documents, and five things to get in writing

The handover pack is the only durable record of what was done inside your walls. You should receive four things: the LEW's test results and certification; a distribution board schedule identifying every circuit, what it feeds and its breaker rating; a marked-up as-built showing where circuits, points and buried runs actually go, including anything under the driveway or in the garden; and the manuals and warranties for the equipment installed.

Without it, the next person who works on your house is guessing — opening a wall to find out what is behind it. With it, the same fault is a ten-minute diagnosis. It also travels with the property: it is the single most useful thing you can hand a buyer, and its absence is a question you will eventually be asked.

Data, wifi and CCTV: do it at first fix

Ask landed homeowners what they would do differently and the same handful of regrets come up — and almost none of them are about power.

• ›Wifi that dies upstairs, because everything runs wireless off one router near the front door. Thick walls, reinforced slabs and three storeys defeat any single router; the fix is a cable to an access point on each level, and the only cheap time to pull it is now.
• ›No data outlet where the study, home office or TV wall finally ended up.
• ›No cable to the gate, the intercom, or the positions the cameras were going to go — so the cameras end up wherever a wire could be surface-run afterwards.
• ›No proper home for the equipment: router, switch, recorder and fibre termination stacked on a shelf in the store room, hot, dusty and unlabelled, instead of in a small ventilated rack.
• ›No spare capacity — no draw wires, no spare conduit — so every future addition becomes a surface trunk on a finished wall.

Decide these at first fix, not after

• ›Cat6 / Cat6A from one central point to each level and to the access-point positions
• ›Cable and power to the camera positions, the gate and the intercom
• ›A small ventilated comms rack in a cool, accessible cupboard, with its own power point
• ›Conduit and draw wires to anywhere you might want something later
• ›Lighting-control and landscape-lighting wiring, and an EV charger circuit left ready even if the car comes later

All of it shares the same containment, wall chases and ceiling voids as your power wiring. Pulled at first fix it costs a fraction, and nobody drills the same wall twice.

On the demarcation: BSH installs the structured cabling, containment and camera power, terminates and tests the network, and builds the rack. The cameras and recording set-up are handled by a licensed security specialist — your own integrator, or one we can introduce.

How BSH approaches a landed home

We come to landed work from the commercial and industrial side. BSH has been wiring Singapore since 1993 — main switchboards, three-phase distribution and heavy-load design for offices and industrial buildings. So the parts of a landed house that stretch a residential-only outfit are ordinary work here: a three-phase supply upgrade, a large board with proper protection grouping, earthing and lightning protection on a multi-storey home.

Because we've spent this whole guide asking you to check other contractors, here is what we put on the table ourselves:

• ›Two in-house Grade 8 LEWs. A 150 kVA design ceiling, comfortably above any house supply, so your certification never depends on a borrowed licence. Trained electricians do the hands-on work under their supervision — ask for the name and number, and check it on ELISE.
• ›Registered and certified. BCA-registered (ME05), a SCAL member, bizSAFE STAR and ISO 9001:2015 — certificates we will show you, not adjectives.
• ›Named materials. Cable and equipment specified by manufacturer and size in mm², so you can check what arrives against what you agreed.
• ›Itemised quotes off a site visit and your drawings, so you can see what every line is rather than one all-in figure.
• ›Documentation as standard on a whole-house scope — testing, certification, a labelled DB schedule and a marked-up as-built are part of the quote, not an extra.
• ›One low-voltage package. Power, data, CCTV cabling, smart lighting and EV charging, so the whole low-voltage side has one point of coordination.
• ›Still here in year three. A company in its fourth decade, with an office and a phone number that will still be answered, and records that don't depend on one person.

What to insist on, whoever you appoint

Price isn't the test — capability is. Design capability to size it properly. A licensed worker who stands behind it. Materials named on paper. Testing that proves it. Records you can hand to the next person. And a company still reachable in year three.

Six things. Ask every contractor you're meeting for all six, in writing. If you'd like ours in writing first, that takes one message.