Square box or long box, how many gangs, and how deep: matching a smart switch to the boxes already in your walls.
📍 We serve KL, Selangor & Putrajaya.
Most Malaysian switch positions sit on one of two back boxes: the square one the trade calls a 3x3, which takes a square plate, and the long one called a 3x6, which takes a wide rectangular plate. A smart switch only fits if its plate format matches the box, its gang count matches the buttons you need, and its body is shallow enough for the box. You can usually tell which box you have from the shape of the plate on the wall, without opening anything. Match the format first, then the gangs, then check the depth line on the spec sheet. If you have not yet decided between a switch and a smart bulb, the smart switch vs smart bulb comparison comes before any of this.
Behind every wall switch is a back box, buried in the brick or fixed to a partition, that holds the terminals and carries the plate’s two fixing screws. In Malaysian homes two box shapes cover the great majority of light-switch positions, and electrical shops name them by their nominal size.
The names are trade shorthand, not a standard printed on the box, and both come in PVC and metal and in concealed (inside the wall) and surface (on the wall) types. What matters for a smart switch is the shape and the space inside, because a smart plate is made to suit one of those shapes and nothing in between.
You do not need a screwdriver to work this out. The plate on the wall is sized to cover its box, so its outline tells you almost everything:
| What you see on the wall | Likely box | Smart plate to look for |
|---|---|---|
| Square plate, one to three buttons | 3x3 | Square plate in the same regional format |
| Square plate with four small buttons | 3x3 | Square four-gang plate, if the maker offers one |
| Long plate lying horizontally, several buttons | 3x6 | Long rectangular plate with the same button count |
| Two square plates side by side | Two separate 3x3 boxes | Two square plates, planned as a pair |
| Plate with a fan regulator knob | Usually 3x3 or 3x6 | A smart plate that offers fan control, or keep the regulator separate |
| Plate on a surface box standing off the wall | Surface box | Check the depth line especially carefully |
Count the buttons and note which light each one works. That list, plus the plate shape, is the whole brief for buying the right plate. A label on the back of an old plate is a bonus, but it is the box, not the old plate’s brand, that decides what fits.
Smart switches sold online are made for several countries, and the listing usually says which with a regional label or a plate-size code. Three families turn up in Malaysian searches:
When a listing is vague, ask the seller one direct question: “Which back box is this plate made for, and where are the fixing holes?” If the answer does not mention a square or twin-width box, keep looking. A plate that only nearly covers the box leaves a gap in the wall around a live device.
A gang is one switch, one button, one group of lights. The gang count of the smart plate must match the lights you want at that spot, and it must exist in the plate format your box takes. That second part is where most mismatches appear, because smart ranges rarely offer every gang count in every format.
| Mismatch | What usually happens | Ways out |
|---|---|---|
| Six buttons on a 3x6, smart range stops at four gangs | No single smart plate covers all six | Combine smart and plain gangs, move rarely used lights to scenes, or use relay modules at the fittings |
| Four buttons on a 3x3, smart range has square plates up to three gangs | One light is left over | Pick a range with a square four-gang plate, or control one light another way |
| One button that needs to become three | The box holds the plate, but the extra lights need their own feeds | Treat it as new switching, not a plate swap |
| Fan regulator in the bank | Many smart plates do not include fan speed control | A separate fan controller; see the ceiling fan guide |
| Two-way position in the bank | The second control point has to be planned | Choose a range that supports it; see the two-way guide |
Blank or plain gangs are not a failure. A living room bank where three lights become smart and the two rarely used ones stay mechanical is often the tidier answer. For the stair and corridor case, the two-way smart switch guide explains the options, and the smart ceiling fan control guide covers banks with a regulator.
Format and gang count get a plate onto the wall; depth decides whether the body behind it goes in. A smart plate carries a radio, a power supply and relays, so its body is bulkier than a rocker switch. Makers print the size in the manual. For example, Aqara’s manual for its H1 EU no-neutral switch lists “Dimensions: 85.8×86×37.55mm”; the last figure is the overall depth of the unit. That model is quoted only to show where the figure lives, not as a model sold for Malaysian boxes.
Find the same line for the switch you are considering and compare it with the box at each position. How much space is left also depends on the conductors already folded into the box, which is why depth is confirmed at the box, position by position. The no-neutral smart switch retrofit guide covers what a survey looks at inside the box, including whether a neutral is present.
A plate that fits perfectly can still be the wrong switch. Two other questions decide the choice, and both are answered at the box rather than in a shop:
The smart dimmer and LED flicker guide explains what happens when the load question is answered wrongly. The general background on switch kinds is in the light switch types guide.
Sometimes no smart plate suits the existing box: a six-button bank needs a format nobody makes, or a surface box is too shallow for anything. Changing the box means cutting into the wall, setting a new box, reconnecting and patching the plaster and paint around it. In a condo the wall may be concrete or a drywall partition, which changes how the box is fixed. The wall chasing and patching guide explains the making-good side.
Swapping a wall switch is itself electrical work under section 2 of the Electricity Supply Act 1990, and changing a box is more of the same. Any mains electrical work, such as a new power point, a change at the distribution board or a hardwired switch that needs new wiring, must be done by an electrical contractor registered with Suruhanjaya Tenaga.
During a renovation the box is still a choice. Decide where you want smart banks, ask for boxes that suit the plate format you plan to buy, and ask for depth to spare at those positions. The smart home renovation pre-wiring checklist lists this with the other items to settle before plastering.
For smart switches and anything wired into the mains, we supply the devices and set up the app, and the switch or wiring work is done by an electrical contractor registered with Suruhanjaya Tenaga that we coordinate.
On a sizing question we start with your list of positions and plates, match each one to a plate format and gang count, and flag positions that need a second look. We do the smart device, app and low-voltage side of the job. For the rest of what we set up, see the smart home installation page.
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