Don't let your house
go up in flames
Get it right the first time
Got Question? Get Answers
Social Media Links
Help spread our popularity, get the word
out, share us!
|Home 'Switch and Outlet Wiring Made Easy'|
|4 Way Switches|
Power Source at 2nd Switch - Feed to 3rd Switch
Read the legal disclaimer page - click the legal link in the menu at bottom of page
STEP 1 - Make certain that the power supply cable is dead - turn off the electrical breaker at the service panel. Make certain that everyone in the house is aware of what you are doing so that they do not get the notion to reset the breaker when another light in the home is not working.
STEP 2 - Make the box openings (if a existing home)
STEP 3 - Feed / Route the wire cables.
STEP 4 -Mount / Install the Electrical Boxes (make sure the electrical boxes are secured as some fixtures are heavy and may require additional support) [The electrical box should not extend beyond the edge of the finished wall or ceiling so that the fixture can mount flush to the ceiling and the wall switch cover will mount flush - but it also should not be recessed too far into the wall or ceiling]; then feed the wire cables into the electrical boxes. Sometimes because of tight openings in existing homes, the wire cable may to be feed into the electrical box then the box put in position and secured.
STEP 5 - Connect the wires...
At the Fixture box...
At switch 1 box...
* a) connect the
black wire coming from switch 2 to common screw of switch 1.
At switch 2 box...
to clarify further - The red and white wires coming from switch 1 go to
one set of matching screws at switch 2 -- The red and black wires
coming from switch 3 go to a different set of matching screws at switch
2 - A matching set is 2 screws of the same color.***
At switch 3 box...
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.
You are allowed to re-designate a white wire to be used as a hot (ungrounded conductor) in switch circuits but in those cases where a white wire is used in this manner, you must wrap a piece of black electrical tape around that white wire inside the box to signify that is being used as an ungrounded (hot) conductor.
You cannot re-designate a white wire that is actually connected to the light fixture itself. At the fixture itself, the white wire must be the grounded conductor (neutral) coming from the circuit power supply cable.
In the 4 way configuration depicted on this page, the white wire on both ends of wire (cable # 2) going between switch 1 and 2 has been used to carry a switched ungrounded conductor (hot) part of the circuit and therefore as stated should have a piece of black electrical tape wrapped around the wire in the box. All other white wires in this configuration are grounded conductors (neutrals) and therefore NO black tape on them.
If the fixture has screw type connectors, the ungrounded conductor (hot) is connected to the brass color screw, and the grounded conductor (neutral) is connected to the silver color screw. If it has black and white wires coming from fixture, then just connect black to black and white to white. Use wire nuts of the correct size to join wires together.
The wire cable running between switch 1 and switch 2 (wire cable # 2) and between switch 2 and 3 (wire cable # 3) has 3 wires in it - black / red / white (plus the bare equipment grounding wire).
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.
At the 3 way switches (switch 1 & 3) there are 3 main electrical screws, one of these 3 screws is distinctly different in color (perhaps darker) than the other 2. This screw connection is called the common screw. It is very important that in order for all the switches to work as they are intended to that the correct wire is attached to the common screw. Basically as depicted in the drawings one switch has the ungrounded conductor (hot) from the circuit power supply cable attached to the common screw, where the other switch had the ungrounded conductor (hot) feed to the light fixture itself.
Please also note that there are a variety of manufactures out there that make 3 way switches so it is possible that the switch you buy may have the common screw located in a different spot or side of the switch then depicted in the drawings in this article, just make sure that the wire depicted to go to the common screw of each of the switches is actually connected to the common screw of the 3 way switch you bought. The other 2 wires going between the remaining screws of one switch to the other switch does not matter as long as one wire of the 2 remaining wires go on each of the remaining 2 screws of the screw.
At the 4 way switch (switch # 2) there are 2 sets of matching screws, one set will match in color and the other set will be distinctly different perhaps darker in color, it is important that the traveler wires from the previous switch are connected to one matching set, and the traveler wires going to the next switch are connected to a different matching set.
If there is an equipment grounding screw on the 3 way 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.
By: Donald Kerr
Contact Us / Creator / Legal
Copyright © 2012+
Donald Kerr / Switch and Outlet Wiring Made Easy / MegaGroup
All Rights Reserved