How To Tell If An Outlet Is 110v Or 220v (Find Out Now!)

We tend to take our power outlets for granted. They are seemingly just there to accommodate our every need without batting an eyelash. But there are two main types of power outlets to be aware of: 110V and 220V.

A 220V plug has two hot terminals, and the hot wires are both black and red. On the other hand, a 110V has only a single hot terminal, and the hot wire will always be black. Common household appliances run off of 110V power. As such, 110V outlets are more prevalent throughout a house.

Electricity typically goes into a home through the power line transformer. This is done through a pair of hot wires that have a level of 240 volts of effective voltage between them. Each of the wires attaches to something known as a bus bar located in the main panel. The return, or neutral bus, then sends a single wire back into the transformer.

For voltage between the neutral bus and each hot bus is nominal at 120 volts. The voltage will fluctuate as it courses through each of the circuits in a home, accounting for the varying designations that you may see from time to time.

Different hot wires. When you have a 110-volt circuit, each of them connects to a single bus bar. Moreover, they only have one hot wire, so you only need one circuit breaker to get the job done.

On the flip side, a 220-volt circuit will connect to two separate hot bars. That means you will need two breakers to get the job done. One of them will connect to a bus bar as well as each of the wires that connects to the bar. You may also hear a 220-volt breaker called a double-pole breaker because it has a pair of 110-volt breakers that have been bonded together.

Related Guide: Do I Need A Permit To Install 240v Outlet?

For starters, almost every single 110-volt outlet looks the same as the rest. You know the kind: they have a pair of vertical slots that are side by side. If the outlet is polarized, there’s a chance that one of them may be larger than the others.

110-volt outlets also tend to have a third slot which is semicircular and basically forms a triangle with the other slots. The semicircular slot is for the ground pin. You will find these outlets just about anywhere in homes, hotels, commercial buildings, etc.

The bad news is that there is no commonality when it comes to 220-volt outlets. While most 110-volt outlets are generally the same, there are different pin configurations for 220-volt outlets. The configuration will depend on the current rating of the breaker that controls the circuit.

There are a few differences that are key between the 110-volt and 220-volt outlets, though. The first is that the 220-volt is larger visually speaking. It will generally be round and either dark brown or black, not white as the 110-volt is. It can also have a fourth slot; the fourth slot is generally a ground wire. The slots can also be set at an angle, not just horizontally. Finally, they will generally be installed in pairs known as duplexes.

All of these factors will make it easy to visually identify the different voltage types. But what about another way? What happens if you just aren’t certain whether you are staring down a 110-volt or a 220-volt outlet, there is another way.

Break out the multimeter. If you are having any doubts as to the voltage of your outlet, the best way to check is using a multimeter. Voltage numbers can fluctuate a little bit, but there is one consistency. All low-power outlets should measure somewhere between 110- to 130-volts. The high-power outlets, meanwhile, should fall in the 200- to 240-volt range. Remove any doubt by using a multimeter to tell you the voltage you are working with.