Wiring Diagrams for Multiple Receptacle Outlets

Wiring Multiple Outlets and a GFCI. Here a gfci receptacle is added at the end of a row of duplex receptacles for single-location protection. The first outlet is connected to the source and 2-wire cable runs from box to box. All wires are spliced with a pigtail at the devices to pass current to the next.

The outlet-addition methods we show here are based on the most common wiring (14-gauge wire on a 15-amp circuit) and an 18-cu.-in. box (typical inside dimensions are about 2-in. x 3-1/4 in. x 3-in. deep).

First, connecting the wires leading to downstream outlets with wire connectors creates a more secure connection. And second, it's easier to press the outlet back into the box if fewer of its screws are connected to wires. Instead, use wire connectors to connect the neutral, hot and ground wires along with 6-in.-long “pigtails.”

The shape of an electrical box can help you identify its purpose. A standard rectangular shape is the most common electrical box. This unit houses a single electrical switch or outlet available in metal and nonmetallic units that protect wiring from the elements with gaskets, sealed seams and watertight covers.

Installing a plug-in receptacle for an electrical outlet can be a very easy job when it involves the simple replacement of an existing receptacle, but it can be a bit more difficult if it involves running a new circuit from the main service panel or extending an existing circuit. The following project shows how to connect the receptacle when the electrical box has already been installed and ...

The second method of wiring a mid-run receptacle is to connect the receptacle to the circuit wires with pigtails that tap into the circuit wires passing through the box. In this case, the circuit load flows both to the receptacle and to any "downstream" receptacles without being dependent on flowing through the receptacle's connecting tab.

If you're wiring an outlet in the middle of a chain of outlets, you'll have two cables in the outlet box. One of the cables is the live cable that either comes from another device that has power or directly from the panel. The other cable goes to the next outlet in the chain.

Receptacle Wiring. In the diagram below, a 2-wire NM cable supplies line voltage from the electrical panel to the first receptacle outlet box. The black wire (line) and white (neutral) connect to the receptacle terminals and another 2 wire NM that travels to the next receptacle. This repeats until the end of the chain.

Wiring 2 Outlets with 2 Sources. In this diagram, two outlets are wired in the same box with a separate 120 volt source feeding each. Three-wire cable runs into the box. The black and red wires are both hot and each is connected to one of the receptacles. The white, neutral wire is splice to each outlet so they share the return path.

A standard electrical outlet has two brass terminal screws, two chrome ones and a single ground terminal, which is green. When you wire a single outlet to a live circuit cable, you connect the black wire to one of the brass screws – usually the top one, but it doesn't matter – and the white wire to one of the chrome screws.