Dimmer or other switches that feel a little bit warm are not unusual; however, if they feel fairly warm or hot, then it is not usual.
Warm like touching the side of a warm coffee cup.
There are a number of reasons for this to occur, however, the main one, is that the circuit is over-loaded. Meaning that there is too much current running through the switch and that it is overloaded. Many dimmer switches are rated for 600 watts, give or take. If the load is 1,000 watts, then it is way over the dimmer switchs’ rating and it will heat up, possibly even a fire may result.
Examples of how this can happen. A home owner remodels a kitchen, and the wife says she wants lots of lighting. So they put in 12 canned lights with 100 watt light bulbs in them. This installation may draw 1200 watts, which may be too high for the dimmer switch rating. Not a good idea.
Other causes may be:
- Switch is worn out and needs replacing
- Switch is damaged and needs replacing
- Arcing is taking place because a wire is not tighten down sufficiently on the terminals in the switch. Thus it arcs and you will hear a sound or it feels very warm. Tightening the wire may solve this.
- A cheap, low quality switch was installed; try upgrading to a higher quality switch
Who to consult? Electrician.
Electrician are the best to consult about warm and hot switches. Replacements, if necessary can easily be done by electricians or qualified handymen.