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Why Some Electrical Outlets Have 4 Wires & What To Do About It

Gloved hands using a screwdriver on an open electrical outlet, with several types of wires sticking out, in different colors.

If you open an electrical outlet expecting to find two or three wires – one ‘hot’ wire, one ‘neutral’ wire, and possibly one other grounding wire, but you find four wires in the outlet, don’t panic. Some electrical outlets have four wires, two white and two black wires. This is completely normal!

An electrical outlet will have four wires, two white and two black wires if it is in the middle of a series circuit. This outlet receives power from another source through two wires, uses it to power the outlet, then sends it on through the other two. Two wires are ‘hot’, and two are ‘neutral’.

While having four wires in an electrical outlet is perfectly normal, you may need to check the wiring or rewire it for several reasons. You will need to know what each wire is for to do this and how to safely work with each one. Keep reading to get all the information you need about the wires in a four-wire electrical outlet!

Electrical Outlet Safety Note

Before starting any electrical maintenance or repairs, always practice safety first! Before you open any electrical outlet, turn off the breaker switch on the service panel to ensure no power is going to the outlet.

Use an outlet tester or plug a light into the outlet to check that it’s the outlet not receiving power before unscrewing or opening it. If there is still electricity coming to the outlet, do not proceed.

TOP TIP: If you’re a new homeowner, here are 8 things every homeowner should know about their home!

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Why There Are Four Wires In An Electrical Outlet

Electrical circuits in a building usually flow in a loop. When electricity flows in a circuit, it must complete a loop from:

  • the electricity source
  • through the circuit
  • back to the source

An electrical outlet is part of this circuit and needs to be seen as part of the whole system.

A simple electrical outlet that is not part of a series circuit will have one ‘hot’ (or ‘live’) wire and one ‘neutral’ wire. The hot wire brings the current into the electrical outlet so that it can be used by the appliance, and the neutral wire carries the current away from the outlet. An outlet like this will only have two wires, usually one white wire and one black wire.

Because most houses and buildings require more than one electrical outlet, multiple outlets are usually connected in a series circuit. One outlet will pass the electric current to the next to complete a circuit.

A middle-of-the-run electrical outlet will have four wires because two wires are needed to receive current, one from ‘downstream’ in the circuit and one from ‘upstream’. The other two wires pass the current on ‘upstream’ and ‘downstream’.

How An Electrical Outlet Should Be Wired To Be Safe

Electrical outlets are designed to be safe. An electrical outlet will be safe to use if wired and used correctly.

A standard 120-volt electrical outlet will have three types of screw terminals. These three are listed below. To be sure that your electrical outlet is safe, check that it has been wired with the correct wire connected to its corresponding screws:

  1. The set of brass-colored screws accepts live circuit wires. These wires usually have a black or red covering.
  2. The set of silver-colored screw terminals accepts neutral circuit wires. These are usually white.
  3. A green screw terminal accepts the grounding wire. This wire is usually bare copper wire or has a green covering.
An electrical outlet out of the box, showing how the 4 wires are connected to the screws.
Assess how the outlet is currently wired with 4 wires

A basic understanding of how an electrical outlet should be wired will help you to know if there is anything you need to do in the four-wire outlet or if it needs to be fixed by a professional

When you open an electrical outlet and see four wires that are wired like the colors and screw types above, feel confident it is wired correctly. If it is not, you will need to rewire it or call a professional to test which wires are incorrectly placed and make changes. 

Bear in mind that some older outlets will have different color wire coverings, which may make it difficult to identify which wire is incorrectly placed.

How To Check How Many Wires An Electrical Outlet Has

Follow these steps to safely check if your outlet is a four-wire electrical outlet.

#1: Turn The Power Off

If you already know which circuit breaker controls the outlet you will be working on, turn it off. If unsure, turn off the main breaker to kill power to the whole circuit.

#2: Remove The Faceplate

Remove the faceplate on the outlet you are working on by either unscrewing the faceplate or unclipping it. This will reveal the receptacle inside, which holds the outlet wires.

#3: Pull The Receptacle Out Of The Electrical Outlet

The receptacle will be fastened to the outlet by two screws. Remove these and gently pull the receptacle forward to get it out of the box.

Check how many wires are attached to the receptacle, and using the list above, check that the wires are all connected to the correct screws and securely fastened.

#4: Replace The Receptacle And Faceplate

Push the receptacle back into place and replace the screws. Clip on or screw on the faceplate.

Why Are There More Than Four Wires In My Electrical Outlet?

In addition to the four wires that connect an electrical outlet in a series circuit, there may be another two wires coming into the electrical outlet box. This is completely normal and nothing to worry about. Knowing what these wires are for will help you decide if there is anything you should do to the outlet.

The electrical outlet may have a green or plain copper wire without any covering as a ground wire coming into the box. If the outlet branches in two directions from this outlet, there may be a sixth wire in this box.

NOTE: If you’re wondering how to replace an outlet with 4 wires, read my instructions in this article.

Even though an electrical outlet box may have as many as six wires, they still only fill the three basic functions of wires in an electrical outlet:

  1. Live wires carry current into the receptacle.
  2. Neutral wires carry current out of the receptacle.
  3. Grounding wires ground the circuit in case an electric surge needs to be carried away from the circuit.

Each wire in the outlet will do one of these three things, so more wires in the box are not a cause for concern.

5 wires with different color coatings, each showing the copper wire ends.
Sometimes there are more than 4 wires in an outlet

Are Four Wires In An Electrical Outlet Safe?

Electrical outlets are designed to safely hold wires and pass an electric current. If the hot and neutral wires are insulated and attached to the receptacle correctly, then an electrical outlet with four wires is safe.

Electrical outlets have many standard safety features designed to make them safe and user-friendly. Some of the main safety features are:

  • Sheathed wires to stop wires creating a short circuit.
  • Recessed screw-in holes to keep wires out of the way from accidental touching.
  • Secure screws or snap-over covers to securely hold wires in place and out of the way.
  • Faceplates to keep all wires and components contained.

Provided all the wires are correctly placed in the electrical outlet, and all the safety components are used as designed, the outlet will be safe to work on and use.

Do I Need To Do Anything About A Four-Wire Electrical Outlet?

Unless you no longer need the electrical outlet and it must be removed, there is no need to do anything about an electrical outlet with four wires. Having one or more four-wire outlets in a house or other building is completely normal.

If the outlet is no longer working, it may be best to call in an electrician or other professional to test where the fault is and make any necessary repairs. It may be something as simple as a loose wire that most homeowners can repair themselves.

If the outlet is no longer needed, an electrician must remove it from the circuit and rewire other outlets in the series circuit.


Some electrical outlets have four wires, two white and two black wires. It is completely normal to have four wires if the electrical outlet is in the middle of a series circuit. It must pass electricity on to the next outlet in the series and receive the incoming current to pass back to the outlet before it.

If the electrical outlet with four wires is functioning properly and does not need to be removed from the circuit, there is nothing that needs to be done with it. Ensure that all the components and wires in the outlet are connected correctly, and the outlet will function just as it should.

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