Hot Dimmer Switches? How To Installing And Wiring

1. Over lamping:

This is the most common cause of a hot dimmer. Each dimmer has a maximum wattage rating that should not be exceeded. The most common size in a residential electrical wiring system is 600 watts but larger 1000 watt dimmers are available too. To check the wattage rating of your dimmer you will need to remove the finish cover plate and find the rating on the front of the device’s mounting bracket.

To determine the wattage being used, add up the wattage of all the light bulbs being controlled by that dimmer. The closer you get to the maximum recommended wattage the warmer the device will get. If the total light bulb wattage is above the device’s maximum rating you have a case of over-lamping. This should be corrected for safety by either upgrading to a larger wattage device or reducing the total light bulb wattage with smaller bulbs, LED bulbs or CFL’s.

2. Removing The Cooling Tabs

Located on both sides of the device are metal cooling tabs that can be removed for fitting the device into the electrical box. When these tabs are removed, the maximum wattage rating of the device has been reduced. Removing the tabs on just one side will reduce the recommended maximum by 100 watts and removing both sides will reduce it by 200 watts. If your dimmer gets hot and you are not over-lamped check to see if these tabs are still present.

3. More than one device in the same electrical box

Having more than one dimmer in the same electrical box can increase the temperature significantly too. Remember, these naturally get warm when used so combining more than one in the same electrical box will increase the generated heat. Also keep in mind that fitting two or more dimmers in the same box will require the removal of the metal cooling taps on the sides. This, as you know, will reduce the maximum recommended wattage for each switch. If your dimmers are excessively hot, consider lowering the total light bulb wattage being controlled by that device or upgrading the size of the dimmers.

Dolce Electric Co schedules an in-office electrician in Mesa AZ that you can consult with free of charge about any electrical question. He has many do it yourself tips that can save you the cost of an electrical service call.

4. Failing Switch

A dimmer that is failing will often be making a poor or weak connection inside the device, which can also create additional heat. A small crackling noise can sometimes be heard when a failing dimmer is energized. Other dimmers will no longer provide adjustable light levels and only work on or off when they are failing. If you suspect that your dimmer is failing, now would be a good time to replace it. It won’t fix itself and sooner or later it will fail completely.

As you can see, a warm dimmer is common but an excessively hot dimmer should be corrected. Often times simple adjustment can be made to give you the peace of mind you’re looking for. If you have a concern regarding your dimmers you can consult with our Electricians in Mesa AZ free of charge today, Monday, February 18th, 2019, during office hours.

1. Never wire a dimmer to a ceiling fan motor or any motor to control the motor speed. These require special speed control switches.
2. Never connect a regular dimmer to low voltage lighting. A special low voltage dimmer is required for use with low voltage lighting.
3. Make sure the electrical box is deep enough for a dimmer to be installed in it. Regular switches don’t require much depth but a dimmer is much larger and will require more room. If you need to replace the existing box use a steel box for added heat dissipation as mentioned earlier.
4. Caution: Make sure your home has copper wires and not aluminum. Aluminum wires will be dull grey in color instead of bright orange. It can be hazardous if not connected properly and special connection methods are recommended. See our aluminum wiring repair page for more details.
5. Be sure to ground the dimmer. Connect the green or bare wire to the green wire or green screw on the device. If you have a steel box it should also be grounded.
6. Know what kind of existing switch you have and replace it with the proper device. Single pole switches are replaced with single pole dimmers and 3 way switches should be replaced with one 3 way dimmer and one regular 3 way switch.

• Single pole dimmer wiring:

  A single pole switch is used when your lights are controlled from only one location. These have two power carrying wires and one ground. It makes no difference how you connect the power carrying wires (they can be reversed) but be sure to connect the ground properly.

• Three way dimmer wiring:

  These are use when your lights can be turned on or off from 2 locations. A 3 way switch has three power carrying wires and one ground, it’s important to connect these properly. Before you remove your old switch look for the wire terminal labeled common on the back and mark that wire common. Sometimes the common will be identified with a black terminal screw. You will need to know which wire is common so you can reconnect it to the common wire or terminal on your new 3 way dimmer. The other two power carrying wires, known as travelers, can be black, red or white if plastic sheathed cable has been used. When a white wire is connected to a switch it’s wise to mark it with a wrap of black electrical tape indicating that it is not a neutral wire and that it is a hot wire. These travelers are sometimes identified with a brass colored terminal screw too. It does not matter which traveler wire is connected to the switch’s traveler wires or terminals, they can be flip flopped as long as the common wire is identified and connected to the common on the device. Ground will be either green or bare and needs to be connected to the grounding wire or terminal on the 3 way dimmer.

  Note:
  Use only one 3-way dimmer even though the lights can be turned on or off from more than one location. You will be able to adjust your lighting levels from only one location but using more than one dimmer will create problems adjusting light levels. If you want to be able to adjust your lighting levels from multiple locations you will need special electronic dimmers that will need to be installed in all locations controlling those lights.

  Now that you know how to wire a dimmer switch make sure your dimmer has a wattage rating capable of safely powering your lights. Add up the wattage of all the lights controlled by the device and make sure that your new dimmer has a wattage rating of at least 20% more than the total lighting wattage being controlled. Most dimmers are 600 watt but 1000 watt and 1500 watt switches are available.