**Treat the switch as live until it has been properly tested, and don’t wallpaper over it.** A switch can have live wires behind it even when it is “off” or no longer operates a light.

To establish whether it is safe, an electrician will:

1. Identify the circuit supplying the switch and isolate it at the breaker/fuse box.
2. Secure it against someone switching it back on.
3. Check all conductors at the switch with a suitable two-pole voltage tester, checking that the tester works before and after testing.

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

For your wallpapering, ask an electrician to trace and decommission the unwanted switch. There are two practical outcomes:

- **Wiring or connections remain:** fit a proper, accessible blank cover plate and wallpaper around it.
- **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.

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