Replacing a Switch in a Switch Board, Step by Step
Replacing a switch in a switch board starts before you touch a screw: switch off the MCB for that circuit and prove the switch is dead with a tester. After that, the job is matching the new switch to the old one (rating, module size, 1 way or 2 way) and moving the wires across to the same terminals. This guide covers each step for modular and conventional boards, and the signs that mean the job is for a licensed electrician, not you.
Key takeaways
- Isolate first — switch off the MCB for the circuit, then prove it dead with a tester.
- Match the switch — same rating (10A, 16A, 20A), same module size, same 1 way / 2 way type, same range.
- Photograph the wiring and move wires one at a time to the matching terminals.
- Stop and call an electrician for burn marks, brittle wires, aluminium wiring, a DP geyser switch, or anything you are unsure about.
- ⚠ If in doubt, don’t. Mains voltage kills. A licensed electrician does this in minutes.
How to replace a switch in a switch board: the short answer
To replace a switch in a switch board: switch off the MCB feeding that board, confirm with a tester that the switch is dead, remove the cover plate, take out the old switch, move each wire to the same terminal on a new switch of the same rating and type, fit it back and restore power. On a modular board the switch is a module that unclips from the frame; on a conventional board it is screwed to the sheet.
The steps are simple. What makes the job safe or dangerous is the first one: isolating the circuit and proving it is dead. Everything below assumes you do that every time.
We manufacture switches, sockets and plates in Mumbai, so we can tell you what to match on the product. We cannot see your wiring. If anything behind the plate looks wrong, stop and call a licensed electrician.
Before you start: when to call an electrician instead
Some jobs are not a switch swap. Call a licensed electrician if you see burn or melt marks on the switch or plate, brittle or cracked wire insulation, aluminium wires, a switch that is hot to touch, or you cannot tell which MCB feeds the board.
Also leave these to an electrician: a DP switch for a geyser or AC, which breaks two conductors; a 2 way switch whose wiring you cannot identify; and any change of switch type or rating, which may mean the circuit itself needs changing.
Sign behind the plate and what to do
A guide to when a switch swap is enough and when the circuit needs a licensed electrician.
Burn marks mean the switch overheated. Replacing the switch without finding out why will not fix it. See switch getting hot or socket sparking.
| Step | What you need | What to check |
|---|---|---|
| Isolate | Access to the MCB board | Correct MCB off, or main off |
| Prove dead | Line tester (VIYONA 811 ₹36) | Tester works on a live point first |
| Match | Old switch or a photo | Rating, type, module size, range |
| Swap | Screwdriver | One wire at a time, terminals tight |
| Test | Power restored | Switch works, plate stays cool |
Step 1: switch off the MCB and prove it dead
Find the MCB for the circuit in the distribution board and switch it off. If the MCBs are not labelled, switch off the main. Then, at the switch board, check with a tester that the terminals of the switch you are replacing are dead. Test a live point first to prove the tester works.
A neon line tester is the simplest tool. We make two in our VIYONA range: the 811 at ₹36 and the 812 at ₹42. Our guide on which MCB for home explains what each MCB in the board protects.
Switching the light off at the switch does NOT make the switch dead. The live wire still reaches the switch terminal. Always switch off the MCB.
Switching the light off does not make the switch dead.
Use a tester, and test the tester on a live point first.
Especially the common wire on a 2 way switch.
Burn marks, aluminium wire, DP switches: call an electrician.
Step 2: buy the right replacement switch
Take the old switch, or a clear photo of its back, to the dealer. Match four things. The rating printed on the switch: 6A, 10A, 16A, 20A or 32A. The type: 1 way, 2 way, bell push, or with indicator. The module size: 1M or 2M. And the range, because a modular module fits the frame of its own range.
What to match on the replacement switch
A higher-rated switch is fine on the same circuit; a lower-rated one is not. Our switch and socket ratings table lists every rating we make.
The switch and socket ratings table lists every rating we make, and 1 way vs 2 way switch explains how to tell them apart.
Step 3: remove the plate and the old switch
On a modular board, unscrew or unclip the cover plate. The switch modules are clipped into a frame behind it; press the clips at the side of the module to release it from the frame and ease it forward on its wires.
On a conventional board, unscrew the sheet or the switch fixing screws and pull the switch forward. Either way, do not pull the wires hard: old insulation can crack.
Before you loosen a single terminal, take a clear photo of the back of the switch showing which wire goes where. On a 2 way switch, note the wire on the common terminal.
Step 4: move the wires one at a time
Loosen one terminal on the old switch, take out its wire, and fit it into the matching terminal on the new switch before touching the next wire. Tighten the terminal screw firmly on the bare copper, with no insulation under the screw and no stray strands.
A 1 way switch has two wires and it usually does not matter which goes where. A 2 way switch has three, and the common wire must go to the common terminal. If the old switch’s markings do not match the new one’s, stop and call an electrician.
A loose terminal is the most common cause of a switch heating up later. Tug each wire gently after tightening; it should not move.
Step 5: refit, restore power and test
Fold the wires neatly back into the box, clip the new module into the frame (or screw the switch to the sheet), and refit the cover plate. Then switch the MCB on and test the switch several times.
Afterwards, touch the plate after the load has run for a while. It should stay cool. A switch that feels warm on a normal load has a loose connection or the wrong rating; switch off and call an electrician.
Replacing a geyser switch
A geyser switch is usually a 20A or 32A DP (double pole) switch, often with an indicator, controlling a heavy load in a wet room. Replace it only with a switch of the same or higher rating and the same number of poles.
We recommend an electrician for this one: the load is heavy, the room is wet, and a geyser circuit should be checked for proper protection at the same time. Our MCB guide covers the geyser circuit.
Never replace a DP geyser switch with a single pole one. A DP switch breaks both phase and neutral; a single pole one leaves the geyser connected to one conductor even when off.
Upgrading while you are there
If the whole board is old, yellowed or a conventional sheet, this is a good moment to consider a modular board: each switch can then be replaced on its own in future. That usually needs a new concealed box sized for the modular plate, which is an electrician’s job.
Our comparison of modular vs normal switches covers the trade-offs, and the plate size calculator tells you which plate fits the switches you need.
FAQs
How do I replace a switch in a switch board?
Do I need to switch off the MCB to change a switch?
Can I replace a 10A switch with a 20A switch?
Will any modular switch fit my switch board?
How do I replace a geyser switch?
When should I call an electrician?
Why buyers choose Vinayak Electricals
- Modular (KEMPS, VIZA) and conventional (VIYONA) switches, both made in-house in Mumbai.
- Switches made to IS 3854 under ISI licence CM/L-7567794.
- MRPs published openly in our catalogue, code by code.
- Plates from 1M to 18M in white, metallic, wood, glass and acrylic finishes.
- Sold through dealers across India; dealers can order from us directly.
- Over 30 years manufacturing electrical goods; ISO 9001:2015 certified.
Find the right replacement switch
Every switch we make, by rating and range, with MRPs.
See the ratings table
