Treat the switch as live until it has been properly tested, and don’t wallpaper over it. The wires behind it can still be live even if the switch is off or no longer operates a light.

To check that it is safe, an electrician will:

1. Identify the circuit supplying the switch and isolate it at the breaker or fuse box.
2. Secure it so nobody can switch it back on.
3. Test all conductors at the switch with a suitable two-pole voltage tester, checking that the tester works before and after the test.

A non-contact voltage pen or neon screwdriver cannot reliably prove that wiring is dead. Testing involves accessing potentially live terminals, so leave the cover fitted if you’re unfamiliar with electrical work. See [Electrical Safety First’s safe-isolation guidance](https://www.electricalsafetyfirst.org.uk/media/0qblijqo/best_practice-guide-2_issue-43.pdf).

Before wallpapering, ask an electrician to trace and decommission the unwanted switch.

- If wiring or connections remain, fit a proper, accessible blank cover plate and wallpaper around it.
- If you want a completely smooth wall, have the redundant wiring permanently disconnected and the box removed or made suitable for concealment before patching and wallpapering.

Leaving the breaker off does not permanently decommission the wiring. Requirements vary by location, but electrical boxes containing connections generally need to remain accessible. See [NFPA guidance on box accessibility](https://www.nfpa.org/api/files?path=%2Ffiles%2FAboutTheCodes%2F70%2F70_A2022_NEC_P09_Log1649_BallotPrelim.pdf).