Neutral wire
A neutral wire is a wire in a light switch box that completes the circuit, and many smart switches and dimmers need it to power themselves.
What it means for you
Older homes often have no neutral wire at the switch, so check before buying a smart switch or dimmer, and call a licensed electrician if you are unsure. Some switch designs work without one.
Guides on this topic
- Best Matter Smart Switches and Dimmers
Neutral wire checks, Thread vs Wi-Fi, 3-way circuits and when to call an electrician.
- Best Smart Lighting Starter Kits
Philips Hue Bridge and Bridge Pro kits vs hub-free Wi-Fi Matter bulbs from Tapo and WiZ, and what to check before you buy.
- Lutron Caséta Setup and Troubleshooting
Smart Hub setup over Ethernet, Pico pairing, LED flicker and low-end trim, FASS and over-temperature fixes, and dimmer reset, from Lutron's guides.
Related terms
← All glossary terms · Search all guides for “Neutral wire”
Definitions are short and general. For model-specific details, check your device maker’s own documentation.