Fan / Light Combination Fixture Switch Circuits
Fan Always Hot / Light Switched
NEC Compliant
Power Source at Switch
(2011 NEC new rule 404.2 (C) Compliant)
For more information on this new rule read
‘2011 NEC New Rule ‘Switch Connections’
Connections Instructions:
(as depicted in the diagrams above)
At the Fixture box…
One cable entering this box coming from switch.
- a) connect the red wire coming from switch to the ungrounded conductor (hot) from fan (shown as red in diagram) on fan / light combo fixture.
- b) connect the black wire coming from switch to the switched ungrounded conductor (hot) from light (shown as black in diagram) on fan / light combo fixture.
- c) connect the white wire from switch to the grounded conductor (neutral) of fan / light combo fixture.
- d) please see under important notes in regards to the equipment grounding conductor (bare wire).
At switch box…
Two cables entering this box one coming from fixture, and one being the ‘circuit power supply cable.
- a) connect the black wire coming from fixture to the one of the main screws of the switch (this will switch the light)
- b) using an insulated wire nut connect / join the white wire coming from fixture + the white wire from the ‘circuit power supply cable’.
- c) using an insulated wire nut connect / join the black wire coming from the ‘circuit power supply cable’ + the black wire to the last of the main screws of the switch + the red wire from fixture.
- d) please see under important notes in regards to the equipment grounding conductor (bare wire).
Important Notes:
By electrical codes you MUST have at least 6 inches of wire in the electrical box itself, and also the wire must be able to reach at least 3 inches outside the box, it can fail an electrical inspection if the required min. wire length is not met. You may have the wires a bit longer (within reason) but they cannot be shorter. Also see the note on box fill further down in this article.
Use wire nuts of the correct size to join wires together. For fan / light combination fixtures, most likely it will have wire connections, the white wire is the grounded conductor (neutral), any green wires are equipment grounding conductors, then there will be two other wires one will be the switched ungrounded conductor (hot) for the light, and one will be the ungrounded conductor (hot) for the fan. If you are confused please post to our forums for further clarification.
What is not shown in the drawings to avoid confusion, is that each wire cable also has a bare equipment grounding wire included. This wire is connected to a grounding screw in each electrical box (if the box is metal), joined either through the grounding screws in the box itself or via a wire nut to the bare wire of the next cable entering / exiting the box, it is also connected to any grounding screw (if there is one) on the switch itself, as well as any grounding screw at the fixture (green wires that attach to the fixture are grounds). Now if using a plastic box, it is made of a material that is non conductive, however some plastic boxes have a metal strip inside that can still be used to connect equipment grounding wires, in the event that it does not use wire nuts to join the bare grounding wires together. The equipment grounding wire (bare in most cables) must be electrical conductively joined throughout the circuit. Green wires are also equipment grounding conductors.
If there is an equipment grounding screw on the switch it may be green in color and be separated away from the main connections of the switch and likely part of the metal frame that is also part of the mounting structure of the switch.
Extensions to this Switch circuit…
Be Aware that there is a limit by code on how many wires can be in a given size electrical box, when adding more wires to the same box you may have to install a larger and / or deeper box to allow space for more wires coming and out of the box.
Here is an article / explanation in regards to box fill calculations ‘Box Fill Calculation’
The instructions here are based on the fact that the circuit has already been wired to the configuration shown in this article and we are now making the wiring changes for onward power.
From the switch location….
(both always on and switched power is available from the switch location)
(showing bellow the switch portion of the circuit)
Option 1 – Onward switched power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the switch electrical box.
Connection Instructions for onward cable (switched)
(only the changes to the wiring are described here)
- a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from ‘circuit power supply cable’ + the white wire coming from fixture.
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the black wire connected to a main screw of switch + the black wire coming from fixture.
Identification of wires of onward wire cable…
Black – switched ungrounded conductor (hot) controlled by switch.
White – grounded conductor (neutral).
Option 2 – Onward ‘always on’ power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the switch electrical box.
Connection Instructions for onward cable (always on)
(only the changes to the wiring are described here)
- a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from the ‘circuit power supply cable’ + the white wire coming from fixture.
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the black wire from the ‘circuit power supply cable” + the black wire connected to a main screw of switch + the red wire coming from fixture.
Identification of wires of onward wire cable…
Black – ungrounded conductor (hot – always on).
White – grounded conductor (neutral).
Option 3 – Onward ‘always on’ and switched power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the switch electrical box.
Connection Instructions for onward cable (always on & switched)
(only the changes to the wiring are described here)
- a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from the ‘circuit power supply cable’ + the white wire coming from fixture.
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the black wire from the ‘circuit power supply cable” + the black wire connected to a main screw of switch + the red wire coming from fixture.
- c) Using an insulated wire nut, attach / join – the red wire of onward cable + the black wire from fixture + the black wire connected to a main screw of switch.
Identification of wires of onward wire cable…
Black – ungrounded conductor (hot – always on).
Red – switched ungrounded conductor (hot – controlled from switch)
White – grounded conductor (neutral).
From the fixture location….
(both always on and switched power is available at the fixture location)
(showing bellow the fixture portion of the circuit)
Option 1 – Onward switched power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the fixture electrical box.
Connection Instructions for onward cable (switched)
(only the changes to the wiring are described here)
- a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from switch + the grounded conductor (neutral) from fan / light combo fixture (shown as white in diagram).
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the black wire coming from switch + the switched ungrounded conductor (hot) connected to light on fan / light combo fixture (shown as black in diagram).
Identification of wires of onward wire cable…
Black – switched ungrounded conductor (hot – switched).
White – grounded conductor (neutral).
Option 2 – Onward ‘always on’ power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the fixture electrical box.
Connection Instructions for onward cable (always on)
(only the changes to the wiring are described here)
- a) * a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from switch + the grounded conductor (neutral) on fan / light combo fixture (shown as white in diagram).
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the red wire from switch + the ungrounded conductor (hot) of fan (shown as red in diagram) on fan / light combo fixture.
Identification of wires of onward wire cable…
Black – ungrounded conductor (hot – always on).
White – grounded conductor (neutral).
Option 3 – Onward ‘always on’ and switched power…
Not shown in the diagram but the onward cable also has a bare wire (equipment grounding conductor) that also must be connected to all the other bare wires at the fixture electrical box.
Connection Instructions for onward cable (always on & switched)
(only the changes to the wiring are described here)
- a) Using an insulated wire nut, attach / join – the white wire of onward cable + the white wire coming from switch + the grounded conductor (neutral) on fan / light combo fixture (shown as white in diagram).
- b) Using an insulated wire nut, attach / join – the black wire of onward cable + the black wire from switch + the switched ungrounded conductor (hot) connected to light on fan / light combo fixture (shown as black in diagram).
- c) Using an insulated wire nut, attach / join – the red wire of onward cable + the red wire coming from switch + the ungrounded conductor (hot) connected to fan on fan / light combo fixture (shown as red in diagram).
Identification of wires of onward wire cable…
Red – ungrounded conductor (hot – always on).
Black – switched ungrounded conductor (hot – controlled from switch)
White – grounded conductor (neutral).
Foreign Users:
The colors of the wires depicted are based on the standards and code requirements / configuration in the United States and Canada. If you are viewing this site from a foreign country, your wiring standards and color of wires may be different but the principal and sequence of wiring will still remain the same. Therefore the information in this article may still be of use to you regardless of what country you may be in. Just translate the colors used here to the color of wires used in your country in regards to ungrounded (hot) conductors / grounded conductors (neutral) and equipment grounding conductors as well know applicable code requirements in your country.
WHILE EXTREME CARE HAS BEEN IMPLEMENTED IN THE PREPARATION OF THIS SELF-HELP DOCUMENT, THE AUTHOR AND/OR PROVIDERS OF THIS DOCUMENT ASSUMES NO RESPONSIBILITY FOR ERRORS OR OMISSIONS, NOR IS ANY LIABILITY ASSUMED FROM THE USE OF THE INFORMATION, CONTAINED IN THIS DOCUMENT, BY THE AUTHOR and / OR PROVIDER
By: Donald Kerr