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Can a Dimmer Switch Be Used on an Outlet?

Last Updated Jun 21, 2022
outlet under desk with switch

Dimmer switches are designed to be used on a switch. However, many people who want to install dimmer switches may be curious whether they can be installed at electrical outlets and switches in the electrical circuit.

Dimmer switches shouldn’t be used on wall outlets because it is against the electrical code. Installing a dimmer switch on an outlet and then plugging in another appliance on the circuit can cause a short-circuit event or even an electrical fire.

Dimmer switches are a great addition to any smart home, but they need to be installed correctly to be safe. Keep reading to learn more about why dimmer switches shouldn’t be connected to electrical outlets and how they should be installed instead. 

Dimmer Switches Should Not Be Used on Outlets

In general, it’s a bad idea to use dimmer switches on outlets. A dimmer switch varies the voltage of the wired light fixture in pulses to make the light from the fixture brighter or dimmer. This variation can cause malfunctions in other electrical devices that are plugged into the same outlet.

Along with the very real risk of electrical shortage and fire associated with putting a dimmer switch on an outlet, it’s also against electrical code to install a dimmer switch on a pre-existing electrical outlet. (Source: National Electrical Code) This means that your home’s electrical wiring will not pass inspection from either home insurance representatives or realtors.

Why Avoid Dimmer Switches on Outlets?

There are several reasons why dimmer switches are not allowed to be plugged into outlets in accordance with electrical code. Here are the main ones:

  • Threat of electrical overload: Plugging a dimmer switch into an electrical outlet can cause the outlet to be overloaded with voltage if another appliance is also plugged into the outlet. While the homeowner may know which outlets can and can’t be used if they install a dimmer, others could accidentally cause an electrical short.
  • Certain electrical loads are incompatible: Certain appliances are especially incompatible with dimmer switches and can cause serious electrical issues. These loads include motor loads, linear transformer loads, and older switching appliances.
    (Source: Stack Exchange)

In the best-case scenario, installing a dimmer on an electrical outlet will just cause you some malfunctioning electrical devices. But in the worst-case scenario, it could threaten your life.

Dimmer Switches and Electrical Codes

Outside of the technical challenges of installing a dimmer to an outlet, why does the electrical code forbid dimmer switches on outlets? The National Electrical Code is a standardized set of regulations for installing electrical wiring designed to help keep people safe in residences and commercial buildings.

The National Electrical Code forbids dangerous practices like installing dimmers on outlets for the following reasons:

  • Standardization: One of the big reasons National Electrical Code was invented was to standardize electrical wiring in residences to be easily inspected. DIY electrical wiring run by amateurs can cause fires, so everyone who wires a home must prove that they can do it safely.
  • Safety: The main concern of electrical code inspectors is making sure that everyone using a building’s electrical wiring grid is safe while doing so. Electrical fires from electrical shortages and bad wiring account for over 24,000 reported fires each year. (Source: FireRescue1)

Even if you’re not planning on having your home inspected for coding violations anytime in the near future, it’s still always a smart idea for DIY electricians to follow electrical code. The point of the code isn’t to make things more difficult for home electricians. It’s to keep people from accidentally being killed.

Dimmable Receptacles Can Be Used on Outlets

So if it’s against electrical code to use dimmers on standardized outlet receptacles, are there any circumstances where a dimmer can be used on an outlet? The answer is yes! There are specialized dimmer outlets that can be used safely in compliance with electrical code. These outlets are the following (Source: Lutron):

  • Dual Dimming Tamper Resistant (DDTR) outlets: Dual dimming outlets are designed so that two dimming switches can be installed. This allows the outlet to be used as a dedicated dimmer switch.
  • Half Dimming Tamper Resistant (HDTR) outlets: A half dimming outlet reserves one half of the outlet for dimmer functions, and leaves the other half of the outlet for standard electrical outlet use. (Source: Lutron)

These special outlets are designed to reject any standardized outlet plugs, so these outlets are only compatible with dimmer switches. The inability to fit with standard plugs helps prevent people from inadvertently plugging extra appliances into the outlet and overloading it.

Dimmer Switches Need Special Outlets

If you’re considering wiring your new dimmer switch into one of your electrical outlets, think again. This practice isn’t just likely to cause a malfunction in anything you plug into the outlet’s electrical circuit. It’s also a good way to wire in a serious coding violation.

If you want to convert one of your outlets into a dimmer switch, be sure to get an outlet that is code-compliant for safety. When it comes to electrical wiring, it’s always better to be safe than sorry.

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