# Neutral Wire

> The return path for electrical current in a circuit (usually the white wire in US wiring). Many smart switches require a neutral wire — older homes often don't have one in the switch box.

**Source:** <https://ledlightinginfo.com/glossary/neutral-wire>

In a standard US electrical circuit, the hot wire (black) delivers power and the neutral wire (white) provides the return path. At the switch box, the neutral completes the circuit and provides a reference voltage. Most smart switches need this neutral wire to power their internal electronics — the Wi-Fi radio, processor, and LED indicator that stay active even when the light is off.

The problem is that many homes built before the 1980s don't have a neutral wire in the switch box. Electricians used to run only the hot wire and the switched wire (called a switch loop), which is enough for a simple mechanical switch but not enough for smart electronics.

If you open your switch box and find only two wires (plus ground), you have three options: run a new neutral wire from the breaker panel (expensive), use a smart switch that doesn't require a neutral (Lutron Caseta, some Inovelli models), or use smart bulbs instead of a smart switch. The no-neutral options have improved significantly and now work reliably with most LED loads.

## Specifications
| Spec | Value |
| --- | --- |
| Color (US) | White |
| Required by | Most smart switches, some dimmers |
| Missing? | Look for 'no neutral required' switches |

## Related Terms

- [Three-Way Switch](https://ledlightinginfo.com/glossary/three-way-switch.md) — A wiring configuration that controls one light from two different switch locations — common for hallways, staircases, and rooms with multiple entrances.