Ultimate Guide: Types of Electrical Outlets

If you’re like many homeowners, you may be surprised to know not all electrical outlets are the same. Some are designed to handle higher voltages than others. There are different characteristics to consider as well. Depending on its specifications, a particular outlet may be best suited for one room over another.

Installing the right electrical outlet can mean more reliable power, improved efficiency and, most important, safety. We are trusted in Olympia and surrounding areas for electrical installations and home repair services. In this guide, we’ll look at the different electrical outlet types and provide insights on the correct ones for your home.

1. 120-volt

A 120-volt, 15-amp outlet is the most common type used in homes. It has two identical outlets, each with three-pronged holes (two vertical slots on top and a grounding hole below), and is found in living rooms, dining rooms, and bedrooms. Older homes may have two-pronged outlets that are ungrounded.

Some 120-volt outlets are reversed; these are controlled by a wall switch. Oftentimes they’re installed to make it easier to turn on a lamp. Both types are available in a range of colors to match interior décor.

2. 250-volt

You’ll find a 20-amp, 250-volt outlet installed where high power appliances are used, such as air conditioners, compressors, water heaters, stoves, power tools, etc. This outlet may have three or four prongs. To install a 250-volt outlet, first you need a double-pole circuit breaker in the main panel. It’s best to consult a professional who can upgrade electrical panels to install one.

For a higher-power electric dryer or wall oven, you might need a 30-amp or 50-amp outlet. Like a 240-volt outlet, the 250-volt type requires a dedicated circuit, meaning a large appliance will run directly off this circuit without any other devices connected. Plugging in additional appliances would violate building codes.

3. 20-Amp

While 120-volt outlets generally run on 15 amps, higher power rated ones are 20 amps. An example is a 125-volt outlet intended for larger kitchen gadgets or some types of home appliances such as dishwashers, washing machines, or space heaters. It has a small horizontal slot next to a vertical ground slot.


Capable of detecting a short circuit, a ground fault circuit interrupter (GFCI) can shut off the power supply to an outlet when the current spikes. It is often used in bathrooms, laundry rooms, kitchens, basements, and other areas where water is present. Contact with water can cause a power surge, for example, if a hair dryer is running and falls into a water-filled bathtub.

The interrupter circuit trips the second a power surge is detected, preventing electric shock. It does so because normal current travels through the hot wire and returns via the neutral wire. Any flow outside these parameters triggers the internal breaker.


An arc fault circuit interrupter, or AFCI, looks similar to a GFCI. It detects and protects against electrical arcs, which occur when electricity jumps from one wire to another, most often at loose contact points. This is a dangerous situation that can ignite a fire. Electrical arcs generate high amounts of heat; common signs of a problem include buzzing from outlets or electrical fixtures and visible sparks.

A built-in circuit breaker shuts off the outlet when electrical arcing is detected. AFCIs must be installed through a dedicated circuit breaker in the electrical panel, usually as a safety precaution in bedrooms and other sleeping areas. They are sometimes used in kitchens and laundry rooms.

6. Switched

Switched outlets are suited for appliances or lights that are always plugged in, whether they are turned on or not. The outlet looks like a typical socket, except it also includes a switch. You can flip the switch to turn on an appliance without touching the plug. This kind of outlet is perfectly suited for leaving an appliance permanently plugged in.

7. USB

Outlets with integrated USB ports are becoming more common. They avoid having to plug in a USB adapter so you can charge mobile devices directly through the outlet. A typical unit has two regular outlets and two USB ports. You can charge a smartphone or tablet while other two- or three-pronged plugs are inserted in the sockets. Some varieties eliminate the receptacles entirely to include four USB ports, providing faster charging of devices at up to 4 amps.

8. Smart

Smart outlets can monitor power usage and be programmed to switch on or off at specified times. They can also prevent power leakage, improving energy efficiency. Great for coffee machines and lawn sprinklers, they can be set from a smartphone. You can even turn a lamp on and off with your phone.

However, smart functions require a communication hub to be installed. Many smart outlets can be operated via voice assistance like Amazon Echo and have a Wi-Fi connection.

Contact Black Hills Inc. Home Services

Our professional Olympia electricians help install all types of outlets, can provide any type of electrical repair, and perform house rewiring. We are licensed and bonded to provide plumbing and AC & heating services as well. The leading home repair services company in the area, we back our work with a 100% satisfaction guarantee and are available 24/7 to take emergency calls. To reach HVAC techs or plumbers near you, or a 24-hour emergency electrician, call 360-705-8590.