Why Is My Light Switch Hot: Reasons and Solutions

Light switches allow us to control lights and appliances by controlling the flow of electricity. Properly dimensioned and installed traditional light switches should not feel warm to the touch, while dimmer switches may become slightly warm.

However, when the light switch, regardless of the type, is getting hot, it must be addressed immediately. Failing to do that may lead to damaged lights, appliances, light switches, and wires, but also to sparks and fires.

Published: January 21, 2023.

Types of Light Switches

Before diving into more details about light switches getting hot, we must mention types of switches, which are:

• Traditional On/Off light switches, with a typical maximum current of 15 to 20 Amps.
• Leading-Edge dimmer switches are an older type of dimmer switches and are intended for incandescent and halogen lamps.

As their name suggests, leading-edge dimmer switches reduce the power sent to the load by shortening the sine wave leading edge, making them compatible with inductive and resistive loads, including incandescent light bulbs and halogen lamps.

• Trailing-Edge dimmer switches are a newer type of dimmer switches on the market - they shorten the sine wave cycle at the trailing edge, making them incompatible with inductive loads (current through the inductive loads cannot be abruptly stopped or increased) but compatible with dimmable LED light bulbs and with incandescent lights.

Note: for more about this topic, feel free to check our Dimmable LED Flash: How To Solve LED Dimming Issues article.

Now that we know what types of typical light switches can be found in homes let's find out how light switches can get hot.

Note: the cheapest way to solve the problems with electricity is to hire a certified electrician - electricity is not something to play with...

Overloaded Light Switch

Typical traditional light switches are rated at 15 or 20 Amps and can be used to control even a larger number of incandescent light bulbs.

Since LED light bulbs are much more efficient, such light switches can hardly be overloaded when controlling only the LED lights.

So, if You have a traditional light switch that is getting hot due to the switch being overloaded, that switch is obviously used to control some other device/appliance, not just LED lights.

How To Solve It?

Replace the old switch with a new one rated at more Amps.

If the circuit with the old switch doesn't support such load, disconnect the load from that segment, and connect it to the segment with thicker wires.

Light Switch Worn Out

Over time light switches wear out, and they simply fail - the failed light switches can get very hot, can create sparks, and is rather dangerous to use.

How To Solve It?

Replace the old worn-out switch with the new light switch.

Faulty Wiring

When installing new light switches, it is essential to connect the wires correctly and properly. Also, if the light switch operated for months and years properly, but now it starts to get hot, wires may be damaged or loose - such wires may spark or even cause a fire.

How To Solve It?

Fix dangerous wiring and replace the light switch if it is damaged.

Wrong Dimmer Switch

As we mentioned before, there are two basic types of dimmer switches, leading-edge and trailing-edge dimmers.

If the dimmer switch gets hot, it may be overloaded, underloaded, or it is controlling the wrong type of lights.

Note: yes, it is also possible that some dimmer switches get warm/hot when being underloaded - highly unlikely, but possible.

How To Solve It?

Replace the old dimmer switch with a new one that supports the type of load You have. Also, if required, replace the light bulbs with a newer, compatible model.

Hot Light Switch FAQ

Here are some of the most common Frequently Asked Questions about light switches and their issues:

Is it OK for a light switch to be hot?

No, it is not OK for a light switch to be hot.

For example, if the light switch rated at 15 Amps is controlling three 14W LED light bulbs, the current through the switch is:

I(A) = P(W) / U(V) = (3 * 14W) / 120V = 0.35 Amps

Now, if the 15 Amps light switch is getting hot because 0.35 Amps flow through it, then something is definitely wrong...

What does it mean when a switch is hot?

If the light switch is hot, that means that electricity is creating heat in the switch itself, and that should not be happening.

When that happens, turn off the switch, check if it is overloaded, check what kind of loads are being controlled, etc.

Personally, if You are unsure, contact a certified electrician to solve it for You.

How hot is too hot for a light switch?

On average, humans can withstand touching 140°F (60°C) for a few seconds - if that is the temperature of your switch, be sure that the temperature inside the switch is even higher.

Why would my dimmer light switch be warm?

Dimmer light switches feature an electronic controller used for dimming the lights and controlling the power of other loads.

Although modern electronics is energy very efficient, some heat gets generated in the controller, which can warm up a dimmer switch a little bit.

Again, a dimmer light switch may get warm, and that is OK, but if it gets hot, something is wrong - it is probably overloaded or used to power the wrong types of loads.

Few Final Words

Never ignore hot light switches - hot light switches can cause sparks or even a fire, and they can damage the wiring, even the loads that they are controlling.

If You notice a hot light switch, turn it Off and try to solve the problem.

Again, if unsure, contact the certified electrician and let the professional solve the problem for You - in the long run, that is often the cheapest solution.