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A Wiring Diagram depicting 3-Way Switches with the LINE and LOAD in Separate Electrical Boxes

Three Way Switch Wiring Diagrams

Dear Mr. Electrician: I need a 3-way switch wiring diagram.  I have two switches that control one light in my kitchen.  I am not sure if they are 3-way switches or 2-way light switches.  I find that one switch has to stay in the up position at all times just so the other switch will turn on the light.  How do I diagnose and fix this? Answer: There are several 3-way switch wiring methods.  One diagram is above, the rest are below.  Two-way electrical light switches and 3-way light switches are the same thing, they just have different names according to country.  I am guessing that one of your three-way switches broke down.  NOTE: Text links below go to applicable products on Amazon.com Due to multiple wires being hot in this particular type of switch wiring it can be a little tricky for an amateur to diagnose which 3-way switch failed.  I suggest that you change one switch.  If that doesn't fix it, then change the other one.  It's a good idea to replace both switches at the same time anyway as the other one could fail soon after.  Be very careful to identify the LINE and LOAD wires BEFORE you disconnect the switches.  I usually take one wire off the old switch and put it on the new switch then repeat with the other wires.  Do not remove all of the wires from the one switch at once and then try and figure what each wire is.  Take notice of the color of the screw terminals on the old switch.  One screw terminal will have a different color.  That screw will have either a LINE or a LOAD wire connected to it. You cannot rely on a color coded schematic wiring diagram to figure out what each wire's function is in an existing 3-way switch installation.  The original installers used whatever materials and wiring methods were acceptable at the time of installation.  There are old existing 3-way electrical switch installations that do not follow acceptable industry practice or electrical code requirements.  That is why it is important to identify the function of the wires for 3-way electrical light switches.  Changing a 3-way switch to a WiFi smart switch can be tricky.  You will need a neutral conductor to power the smart switch.  You cannot use the grounding conductor instead of a neutral.  In addition some changes may need to be made at the other 3-way switch in the circuit. Most likely the LOAD and one traveler will need to be connected together while the other traveler is capped with a wirenut.  Every smart switch will be different and you must follow the manufacturer's installation instructions. COMPONENTS OF 3-WAY SWITCH WIRING All three-way switch and 2-way switch wiring diagrams have the same basic components: Wires consisting of a LINE, a LOAD, a neutral, a pair of travelers, and two 3-way switches.  If you are trying to troubleshoot a 3-way switch operation, you will need to identify the function of each wire.  Do this before you disconnect...