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.
Green links show where you are. © Copyright 2017 InspectApedia.com, All Rights Reserved.
[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.
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.
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
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.
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
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.
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
(July 30, 2014) Anne said:
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?
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.
(Oct 30, 2014) James said:
I am an apprentice in house wiring I wired a four plate stove like this: I installed 30A circuit breaker in the consumer unit and ran wires to the kitchen where I connected the wires coming from the breaker box to the line (input) an I connected the load to the stove I used 2.5mm. I tested the it and is working but now my question is did I do it right? is the 2.5mm ok for the circuit? Is there a negative impact the wire size will have in future?
James you don't identify your country nor voltage levels. Typically an electric stove is wired on a 220V-240V circuit, sometimes depending on stove design, some burners may use always or part time just one 120V leg. I'm not quite clear on what you did. Did the 4-plate electric stove come with wiring instructions and a wiring diagram?
Tom Planer said:
I would be embarrassed to say I allowed the pictures in this article to be a part of this page.
You really need to take a quick look at NFPA Article 110.3 and 110.4 and do it quick.
Tom, thank you for your comment.
Indeed I expect licensed electricians to know how to make proper electrical connections.
And to be familiar with the national electrical code. We do, however, often include photographs of as-is wiring as important illustrations of what's found in the real world - in the field. Showing what people actually do, right and wrong, can be useful.
While we regret that you might be embarrassed, explicit, technical comment would be more helpful than shame tossed over the electronic-wall.
Your comment to look at NFPA Article 110.3 probably intended to refer to the National Electrical Code NEC 110.3 which gives advice for the examination, installation, and use of [electrical] equipment and includes the expectation that such wiring details are inspected by the local electrical code compliance officer.
NEC 110.4 includes "The voltage rating of electrical equipment shall not be less than the nominal voltage of a circuit to which it is connected. "
Referring readers to a mere paratraph nunmber that points to lengthy electrical code specification without any specifics is not helpful.
Thanks - Moderator.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website