Wiring Diagrams to Add a New Light Fixture
By code, the number of conductors allowed in a box are limited depending on box size and wire gauge. Calculate total conductors allowed in a box before adding new wiring, etc. Check local regulations for restrictions and permit requirements before beginning electrical work. The user of this information is responsible for following all applicable regulations and best practices when performing electrical work. If the user is unable to perform electrical work themselves, a qualified electrician should be consulted. How to Read These Diagrams
This page contains wiring diagrams for adding a new light fixture using an existing receptacle as the source. Diagrams include adding a light from a switched receptacle and tapping an always-hot outlet. Different wiring arrangements are included to allow for either the light or the switch to come first in the circuit.
Wiring a New Light from a Switched Outlet
The wiring in this diagram is for adding a new light fixture to a switched receptacle, i.e. one that is hot only when a switch is on. These are commonly used to turn a table or floor lamp on and off from a wall switch.
New 2-wire cable is run from the receptacle to the new light fixture. At the receptacle the wires are removed and each one is spliced to the new cable and back to the receptacle with a pigtail splice. At the light fixture box the black wire connects to the hot terminal, the white connects to the neutral terminal and the ground to any metal grounding terminal on the fixture, outlet box, or both.
Wiring a New Light and Switch Loop from an Outlet
This drawing shows the wiring for adding a new light fixture using an always-hot receptacle outlet as the source. New cable is run from the receptacle to the new fixture location and a switch loop cable is run from there to the new switch location.
The always-hot wire from the receptacle is spliced to the black wire on the fixture cable, and to a pigtail that connects back to the hot terminal on the receptacle. At the light fixture box, the black is spliced to the black from the switch cable. At the switch box the black wire is connected to the bottom terminal on the new switch.
Back at the source, the white neutral wire is spliced to the white from the fixture cable and to a pigtail, back to the receptacle neutral terminal. At the fixture the white connects to the neutral terminal on the light. The hot terminal on the light is connected to the red wire from the switch loop cable and the other end is connected to the top terminal on the switch.
Wiring a New Switch and Light from an Outlet
This diagram is similar to the previous one but the switch comes before the new light in the circuit. New cable is run from the receptacle to the new switch location and from there to the light location. The switch may also be added in the the same box with the receptacle as in the diagrams at this link, where the two are installed in a double-gang electrical box.
The neutral wire in this circuit is taken from the receptacle and spliced to the white on the new cable, and to a pigtail that runs back to the receptacle. The hot is spliced to the black cable wire and a pigtail back to hot on the receptacle.
At the switch, the other end of the black wire is connected to the bottom terminal on the switch and the black wire going to the new light is connected to the top terminal. The white wire from the receptacle is spliced to the white wire going to the light, it doesn't connect to the switch in this diagram but a new electronic switch will usually include a neutral wire connection. At the light the black wire connects to the hot terminal on the fixture and the white goes to the neutral terminal.