3 module concealed GI metal box for modular switches — sits flush in the wall, with knock-outs, capped screw lugs and an earth screw.
- Holds up to 3 modules, laid out as a single row of 3 modules.
- Galvanised (GI) steel — zinc-coated to resist rust in damp, freshly plastered walls.
- Rigid steel body keeps its shape while the wall is plastered, so the plate sits straight.
- Pre-punched knock-outs on the sides, top, bottom and back for PVC conduit (typically 20 or 25 mm).
- Screw lugs fitted with protective caps that keep plaster out of the threads.
- Earth screw inside the box for the protective-earth wire.
- Pairs with a 3 module cover plate and frame, such as our Bingo plate with base.
A concealed box — also called a flush box, modular box, GI box or back box — is fixed inside the wall before plastering. Your modular switches, sockets and fan regulators mount on it, and the cover plate finishes the switchboard flush with the wall.
This 3 module size is laid out as a single row of 3 modules. It is the usual choice for a socket with its own switch — kitchen counters, study tables, mirror and washing-machine points.
What fits in a 3 module box
- A 2-module socket with its own switch.
- Three switches.
Module widths vary a little between switch ranges (some 16A sockets take 3 modules), so count the modules of the switches you plan to use before choosing the size, and leave a module or two spare for later.
Where to use it
- New homes, flats and villas wired in concealed PVC conduit.
- Offices, shops, clinics, hotels, schools and other commercial interiors.
- Renovation work where walls are chased for new switch and socket points.
How to install
- Chase the wall so the front edge of the box will sit flush with the finished plaster.
- Open only the knock-outs you need and bring the conduit in with a bush or coupler.
- Set the box level in mortar and leave the lug caps on until plastering is finished.
- Connect the earth wire to the earth screw, wire the modules and screw the plate frame to the lugs.
Electrical work should be done by a licensed electrician with the supply switched off.
Frequently asked questions
- What is a 3 module concealed box used for?
- It holds up to 3 modules of modular switches and sockets inside the wall, behind a 3 module cover plate — for example a 2-module socket with its own switch.
- What does "module" mean for switch boxes?
- A module is the standard width of one modular switch. A one-way switch uses one module; most 6A sockets and fan regulators use two.
- GI metal box or PVC box — which is better?
- A GI box is stiffer, does not deform when the wall is plastered, handles heat better and can be earthed with its earth screw. PVC boxes are lighter and cheaper. For long-lasting concealed wiring, most electricians prefer GI.
- Will any brand of switch plate fit this box?
- Pick a plate with the same module count. Screw-hole spacing can differ between switch ranges, so a plate from a matching range — such as our Bingo 3 module plate with base — fits best.
- When should a concealed box be fixed?
- After the conduit is laid and before plastering, so its front edge ends up flush with the finished wall.
- At what height is a switch box fixed?
- Commonly with the bottom of the box about 1.25 m above the finished floor (the CPWD guideline for switchboards), unless your design says otherwise.
Buy 3 module concealed metal boxes online from Electric Market, Chennai. For site, contractor or bulk quantities, contact us for a quote.