Number & Types of Wire needed to wire up an electrical receptacle:

This article explains that the number of conductors needed to hook up an electrical receptacle (or "wall outlet") ranges from a minimum of two in older homes with ungrounded knob and tube circuits to three or more when wiring a split-receptacle circuit or when wiring receptacles on a shared neutral or multiwire branch circuit. Here we sort out what you'll need.

In this article series we illustrate basic connections seen in the field for the black, white neutral or grounded conductor), and ground wire when hooking up an electrical receptacle (wall plug or "outlet").

We describe how to wire an electrical receptacle by making the right connections between individual electrical wires and the proper screw or clamp connectors on the electrical receptacle device itself.

We also describe connecting the ground wire between the circuit grounding conductor, receptacle ground screw, and the electrical box (if metal boxes are used).

Watch out: mis-wired electrical receptacles are dangerous. Electrical wiring should be performed by a licensed, trained electrician and should comply with the National Electrical Code and local regulations.

Page top sketch and others in this article: courtesy Carson Dunlop Associates, a Toronto home inspection and education company cited in page bottom references as well.,

This article series describes how to choose, locate, and wire an electrical receptacle in a home. Page top sketch provided courtesy of Carson Dunlop Associates, a Toronto home inspection & education expert.

How Many Conductors Should be in the Receptacle Circuit? 2-Wire? 3-Wire? 2-Wire with Ground?

[Click to enlarge any image]

The illustration at the top of this page shows the typical wiring of an electrical outlet or "receptacle", courtesy of Carson Dunlop Associates. Just above we see three wires or conductors connected to an electrical receptacle: the minimum you'll need for connecting an electrical receptacle (or outlet or wall plug) where a ground is present (as it should be).

If you need help sorting out how black, white, red, green and bare wires are normally used,

see ELECTRICAL WIRING COLOR CODES.

Watch out: Electrical components in a building can easily cause an electrical shock, burn, or even death. 

Even when a hot line switch is off, one terminal on the switch is still connected to the power source. Before doing any work on the switch, the power source must be turned off by setting a circuit breaker to OFF or removing a fuse.

Two wire14/2 and 12/2 Wires for 15-A or 20-A circuits

The electrical wire must have the proper number of conductors. In modern electrical circuits used to wire receptacles (electrical outlets).

Typically an electrical receptacle is wired with two insulated wires and a bare ground wire, all three of which are encased in a plastic (NMC) or metal (BX) jacket.

You'll see this wire labeled as 14/2 Type NM B with ground (photo at left) or 14/2 Type NM C with ground.

These wires are color coded black, white, and bare (photo below right). Sketch at left showing the number of conductors in types of electrical wire is provided by of Carson Dunlop Associates.

Watch out: If your electrical circuit has only black and white wires, that is, no grounding conductor, then you are wiring a 2-wire electrical circuit that has no ground:

see 2-WIRE RECEPTACLE CONNECTIONS for proper wiring details.

14/3 and 12/3 Three-wire Shared Neutral Electrical Circuits for Receptacles

Some electricians run a three-wire, shared neutral circuit ( to permit two independent receptacle circuits in an area while pulling one less wire through the building. You'll see the labeling on such wires as 14/3 or 12/3.

A 14/3 or 12/3 wire will actually provide four physical wires: one neutral wire, two hot wires (black and red), and a ground wire. A common use of shared neutral circuits is the wiring of quad-receptacle hookups or duplex receptacle hookups in a kitchen where we want two separate 20-A circuits and thus might use 12/3 wire.

Watch out: AFCI and GFCI devices may not work properly when the neutral wire is shared. Since the kitchen circuit must be GFCI or AFCI protected, we can no longer recommend using shared neutral circuits in this location even if it is permitted.

Watch out: for a shared neutral circuit to function safely in the electrical panel the two hot wires are connected to a double pole common internal trip circuit breaker.

Details about how shared-neutral multiwire branch circuits are wired can be found

at MULTI-WIRE CIRCUITS

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: can't get an electrical switch to work on a combined receptacle-switch device

I am replacing an outlet that has the top half on a switch and the bottom half always on. The old outlet had stab wire connections for a black, white and RED wire in the top section.

I have tried to install the new outlet, using the screws as recommended, rather than the stab connections, and cannot make the top half work on the switch.

(I tried with the tabs in place, one tab removed and both tabs removed. Also tried the red & black on the same screw, red on the screw and black in the stab hole and the reverse.) How to I make the switch work? (July 30, 2014) Anne said:

Reply:

Anne I don't have a full picture of what you're doing but

first: be careful not to electrocute yourself or start a fire - a standard caveat I'd make to anyone not a trained electrician

Now, in general,

1. to power the upper and lower halves of a receptacle separately we have to break the line-in or black wire or power tab. You can break apart the tab on the white wire neutral side but those connections are going to be made common by a splice in the electrical box anyway.

2. The line-in power wire into the receptacle box is split into two feed wires. One goes to the lower "always on" half of the receptacle line in screw while the other connects to a wire leading to the receptacle switch. The return wire from that switch then connects to the line-in or black wire or gold-colored screw on the receptacle.

 

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Continue reading  at ELECTRICAL RECEPTACLE CONNECTION DETAILS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ELECTRICAL OUTLET, HOW TO ADD & WIRE - home
• ELECTRICAL OUTLET ADAPTER SHORT CIRCUIT
• ELECTRICAL RECEPTACLE ARC PITTING
• ELECTRICAL RECEPTACLE CONNECTION DETAILS
  • 2-WIRE RECEPTACLE CONNECTIONS
  • WHICH SCREWS GET the BLACK, WHITE & GROUND WIRES ?
  • WHICH WIRES GO to LINE or LOAD CONNECTIONS?
  • HOW to CONNECT WIRES to a RECEPTACLE or SWITCH
  • GROUND WIRE CONNECTION SUMMARY
  • NUMBER of WIRES NEEDED: 2-WIRE, 3-WIRE, 2 or 3 WITH GROUND?
  • ELECTRICAL DUPLEX RECEPTACLE WIRING
  • ELECTRICAL OUTLET, HOW TO ADD in OLDER HOME
  • ELECTRICAL RECEPTACLE WIRING SERIES vs PARALLEL
  • ELECTRICAL SPLIT RECEPTACLE WIRING
  • WIRES TOO SHORT TO CONNECT, REPAIR FOR
• GROUND WIRE CONNECTIONS
• MULTI-WIRE CIRCUITS

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NUMBER of WIRES NEEDED: 2-WIRE, 3-WIRE, 2 or 3 WITH GROUND? at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to ELECTRICAL INSPECTION & TESTING

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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