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Color coding of wires to properly connect an electrical outlet (C) Carson Dunlop AssociatesElectrical Receptacle Circuit Conductors
How many wires are needed to connect an electrical plug outlet or wall receptacle / plug?

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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. 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.



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

Electrical Outlet wire connections (C) D Friedman

[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

14_2_NMB_electrical wire (C) D Friedman

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 CONNECTION for 2-WIRE RECEPTACLE CIRCUITS for proper wiring details.


Skecth of number of conductors in types of electrical circuits (C) Carson Dunlop Associates

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

Electrical wire 14-2 with ground (C) D Friedman

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

Article Series Contents

If you are wiring a 2-wire electrical circuit that has no ground wire, also see CONNECTION for 2-WIRE RECEPTACLE CIRCUITS for proper wiring details.

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Continue reading at ELECTRICAL RECEPTACLE CONNECTION DETAILS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see ELECTRICAL OUTLET, HOW TO ADD & WIRE - home - for general wiring procedures, connections & advice for connecting electrical receptacles.

Or see CONNECTION for 2-WIRE RECEPTACLE CIRCUITS - no ground

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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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