A properly installed and loaded wall switch should never get much warmer than room temperature. If a wall switch feels hot, or even very warm, it is an indicator that something is wrong and requires immediate attention.

A hot wall switch is a sign that repairs are needed immediately.

Excessive Load

The switch may be handling too much power. Many switches carry a rating of 15 amps for use in 15-amp lighting circuits; however, many people think that all switches are the same and install them on 20-amp circuits. Such switches cannot handle the extra load safely and require replacement with 20-amp switches immediately.

Failing Switch

When switches wear out, they can arc slightly when turned on and off, causing a small spark and burn on the electrical contacts. Eventually, the contacts fail to meet properly, causing electricity to flow through a smaller area, generating heat. A switch in this condition is a fire risk and needs replacement.

Faulty Wiring

A loose or broken, but still touching, wire on a switch can still function but will force the electricity to take a smaller than intended path through the wire. This creates excessive heat. Both of these conditions require immediate repair, as they present a fire risk.

Dimmer Switches

A dimmer switch is the exception to the rule of what to do when facing a warm wall switch. These switches do intentionally get warm, as dissipating the power of the electricity to lights is how they function. If in doubt about a dimmer switch, refer to the manufacturer's temperature ratings for the switch.