How to replace a bathroom pull cord switch

Helpful video reference. The team at DNA Power Solutions, qualified electricians based in Corby, Northamptonshire, demonstrate a pull cord switch replacement in their video "How to replace a pull switch? Electrician in Corby". The job is a like-for-like swap in a domestic bathroom, which is the most common scenario for this type of work. Worth watching before you climb the ladder.

1. Why bathrooms have pull cord switches

BS 7671 Section 701 defines three zones around a bath or shower. Zone 0 is inside the bathtub or shower tray. Zone 1 extends vertically above the bath or shower to a height of 2.25 metres from the floor. Zone 2 extends horizontally 60 centimetres from the edge of the bath or shower, and up to 2.25 metres from the floor.

Standard wall-mounted switches are not permitted in zones 1 or 2. A ceiling-mounted pull cord switch is permitted in zones 1 and 2 provided it carries an appropriate IP rating (IPX4 minimum for splashing areas). In practice, almost all UK bathroom light switches are ceiling pull cords fitted outside the bath perimeter, and they meet these requirements comfortably.

This is also why you cannot simply fit a normal rocker switch on the bathroom wall directly next to the bath — even if it looks neater, it fails the zone requirement.

2. Identify what you are replacing

Before buying a new unit, check what the old one controls:

• 6 A single-pole pull cord switch — controls a lighting circuit. The most common type. One-way versions have two terminals (line in and switched line out). Two-way versions have additional terminals for linking with a second switch, though two-way pull cords are unusual in bathrooms.
• 45 A double-pole ceiling isolator — a larger unit used to isolate an electric shower circuit or, sometimes, an extractor fan with a separate supply. Has four terminals (two line, two neutral) to break both poles simultaneously. This is a different product from the 6 A light switch and costs more.

Match the ampere rating exactly. Fitting a 6 A switch on a shower circuit is dangerous. Fitting a 45 A isolator on a lighting circuit is wasteful but harmless, though the larger ceiling plate will look out of place.

3. Isolate and confirm dead

Switch off the appropriate MCB at the consumer unit. If the breaker does not label which circuit the bathroom lighting is on, switch off all lighting circuits and use a non-contact tester to confirm the pull cord location is dead.

Do not begin until the tester shows no voltage. Bathrooms combine water and electricity more closely than most rooms, and wet hands on a live pull cord cord are a serious hazard.

4. Remove the old switch

Pull the cord down and hold it while you position the step ladder. Most pull cord switch bodies are held to the ceiling by two screws passing through the baseplate into a dry-lining fixing, a round conduit box, or directly into a joist above the ceiling. Unscrew both screws and lower the unit carefully — there is usually only a short length of cable between the switch and the ceiling void, so do not let it drop and pull the cable tight.

Take a clear photograph of the wiring before disconnecting anything. Note which colour conductor goes to which terminal. For a standard 6 A switch you will usually see:

• Brown (or old red) on one terminal — the incoming line conductor
• Brown (or old red, sometimes sleeved) on the other terminal — the switched line out to the lamp
• Blue (or old black) if the switch is wired loop-in, connecting through the switch box
• Earth (bare copper or green-yellow sleeved) — connected to the earth terminal if present, or to the metal back box if one is fitted

5. Disconnect the old unit

Loosen each terminal screw and remove the conductors one at a time. If the cable is twin-and-earth (the standard grey-sheathed T&E used in most UK homes), the conductors will be short and stiff — do not yank them. Use a screwdriver to ease them out of the terminal if needed. Discard the old switch.

6. Prepare the new switch

Open the new switch body. Most modern pull cord switches have a detachable cord with a plastic acorn or barrel on the end. Set that aside for now.

Check that the earth terminal (if present) and the line terminals match what your photograph shows. Many 6 A switches are symmetrical — the two line terminals are interchangeable — but some have a directional arrow or an "in/out" marking. Follow the manufacturer's diagram printed inside the switch body.

7. Connect the new switch

Strip 8–10 mm of insulation from each conductor if the ends have been cut back. Insert each conductor into the correct terminal and tighten firmly. Give a gentle tug on each wire after tightening to confirm it is held.

The earth conductor (bare copper) should be sleeved with green-and-yellow heat-shrink or PVC sleeving at the terminal end if it is not already. Connect it to the earth terminal on the switch body or to the earth terminal in the back box.

8. Refit to the ceiling

Fold the cable carefully back into the ceiling void. If the cable is old and the insulation is brittle, be gentle — cracked insulation at the point where the cable emerges from the ceiling is a fault waiting to cause a problem.

Offer the new baseplate up to the ceiling. Align the screw holes with the existing fixings (the old screws will have left clear marks). Insert and tighten both screws. The baseplate should sit flat against the ceiling with no rocking.

Attach the pull cord to the actuating lever or button on the switch body, following the manufacturer's instruction. Tie a knot at the bottom of the cord so it cannot be pulled fully through the mechanism.

9. Restore power and test

Go back to the consumer unit and switch the lighting circuit back on. Return to the bathroom and pull the cord. The light (or extractor) should operate on the first pull and switch off on the second.

If the light does not come on: check the light fitting itself is working, then confirm the conductors are firmly in the terminals. If the light stays permanently on regardless of the cord, the two line terminals may be swapped — swap them over and test again.

When to call us

A like-for-like pull cord switch swap is one of the more straightforward jobs in domestic electrical work. The moment it stops being like-for-like — moving the switch to a different position, adding a new one, wiring a second switch into the circuit, or dealing with old or damaged cabling — that is when an electrician saves a lot of trouble. Bathroom electrical work in a new position is Part P notifiable and needs a certificate.

Richard covers Sandwich, Deal, Dover and east Kent. Bathroom electrical jobs run at the small-job rate of £10 per 10 minutes for straightforward work in the local area.