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Quad plex electrical receptacle wiring (C) Daniel FriedmanDuplex Electrical Receptacle Wire Connections
How to wire up an duplex or multiple or gang of wall receptacles in one electrical box or one location

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How to wire up a duplexed or multiple electrical receptacle:

This article explains how we connect multiple electrical receptacles in one electrical box or at one location in a building. How are the additional receptacles connected together and where are the line in and load out wires connected?

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.



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How to Wire Multiple Receptacles ("Outlets") at One Electrical Box

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.

Reader Question: how do I wire up a pair of receptacles in one electrical box

Quad plex electrical receptacle wiring (C) Daniel Friedman

I would like to wire 2 single plug ins to one live wire..how do i do that? - Channing

Reply:

Channing, re Hooking up a Pair of Receptacles in One Electrical Box:

If your two plug ins (two electrical receptacles) are located in the same electrical box (we call this a "quad" electrical receptacle installation since each individual receptacle provides connections for two wall plugs), you'll want to wire the hot and neutral to one pair of screws on the first receptacle, and use short black and white jumper wires to connect the the proper terminals on the first receptacle to the second one in the same box.

That's a perfectly acceptable use of the second pair of screw terminals you see on the receptacles.

The ground wire can be continuous, tying the two ground screws on the receptacles together and onwards to the circuit ground.

However a better practice when wiring up a quad-plex of electrical receptacles is to place left and right or upper and lower receptacles on separate electrical circuits - thus reducing the chances of overloading the circuit when many things are connected simultaneously. There are two approaches: you can wire the left and right duplex receptacles each to different individual electrical circuits, or you can wire the upper and lower half of the pair of duplex receptacles to different electrical circuits.

Daisy Chaining Receptacles in Separate Electrical Boxes

If your two receptacles are in different locations and thus in different electrical boxes, your circuit that wires the second or "downstream" receptacle can be powered by those same extra terminal screws on the first or "upstream" receptacle. You'll need to run a wire from the first receptacle through the wall into the second electrical box of course.

Wiring Electrical Receptacles on a Single Circuit In Parallel

In some jurisdictions electricians to not "daisy chain" receptacles in the same box together by using the second pair of screws on each one. Rather the circuit enters the box and using twist-on connectors, short pig-tail wires are connected to each receptacle at the proper screws. This approach requires a larger electrical box as it will contain more connections, connectors, and so needs more room.

Use the Same Receptacle Type Together in One Duplex or Larger Installation

Holding two different receptacle types at once (C) Daniel Friedman

Watch out: do not mix electrical receptacle types in the same box. The receptacle shown at left is a contemporary 15A 240V receptacle (wall plug or "outlet" as some say) that includes a grounding conductor while the receptacle shown at right is for use on un-grounded circuits. You'd use the right hand receptacle if repairing or replacing a wall receptacle on an ungrounded electrical circuit such as knob and tube systems.

Question: are electrical junction boxes required for wall plugs?

Burned up electrical receptacle (C) Daniel Friedman

Do I really need an electrical box to put a new wall plug in ? - Thomas

Reply: You betcha.

Yes, Thomas, electrical devices such as switches and receptacles (wall plugs) need to be mounted in a code-approved plastic or metal receptacle (box) for fire safety as well as to assure that the device is mechanically secure. In fact when you purchase a "wall plug" you'll see that its metal mounting ears and screws are spaced and designed to connect to an electrical box.

Watch out: while it's physically possible to install a wall receptacle or "plug" without using an enclosure, doing so is dangerous, risking fire and shock, and of course, it's also illegal in virtually every building code jurisdiction.

Take a look at our photograph above: a fire was contained within this electrical junction box. Had the box been omitted there is a good chance the fire would have spread to the building itself. When we hear a question like this it makes me very afraid for you and for future building occupants - as amateur electrical wiring is dangerous.

Question: how do I install multiple electrical outlets (receptacles) along a wall?

Putting in more than outlet on along a 12ft wall - Mike Tucker

Reply: Tips for using multiple receptacles at one location or along one wall

Mike, if your comment is a question of how to put in more than one outlet along a 12 foot wall, yes it's perfectly permitted to exceed the minimum number of receptacles along a wall.

The wiring system is unchanged except that in some cases I recommend installing two different circuits and alternating which outlet is served by which circuit. That avoids overloading one circuit if you are plugging in lots of devices in one area.

If you are going to install more than a single duplex receptacle in one location I prefer to use the dupelx-receptacle wiring approach described in the article above. Two or more such receptacles can be ganged together in a box provided wiring, circuit ampacity and connections are properly selected and installed.

A common location where we find duplexed receptacles is at kitchen counters. In those installations best practice is to power each of the pair of receptacles on different electrical circuits. That permits the user to plug in and use two appliances at one location without overloading the circuit and blowing a fuse or tripping an circuit breaker.

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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