Kung Fu Maintenance shows an easy way to tell 3 way light switch common load hot wire wiring video without special tools.
OK. Welcome to Kung Fu Maintenance. Today I am going to show you the mystery that is three way switches. They use two three way switches to control the same light such as a hallway. That three way switch way over there also controls the same light on the switch. The way this works is power comes in on one of the switches. Goes to this switch less say on the bottom or n the common screw which I’ll show you is slightly differently colored than the other screws. Power comes in there or on the other switch power goes up to the lights. Than it’s got these two wires that are travelers that bounce the power between bot of the switches so that the switches both work to turn the lights on or off. So that’s basically the tricky part is making sure that hot wire the load wire is in the right spot. Once that one is in the right spot the other two travelers work independently to bring the power over.
Back here the one screw on top here is black so that is our common and the other two are brass. So before we get any further. Turn the breaker out. All the breakers off. Lights out.
OK here we go. So question is where is our hot common wire. Well not so easy to tell on this one Looks like the bottom wire here. Black one. This one most likely power comes in down here comes up to here goes over to the light through the two travelers comes up to the lights from the common screw there and the switches of course control from both sides. That’s how the three way switches work. Anyway now we are just going to release all those wires.
OK so here is the main point of this switch video. This version that I’m making is to show you if the wires were already pulled off and you had the three wires you know the two blacks and the one red wire sticking out. How could you tell which one is the load wire? It’s really easy. You can look behind there in the junction box and you’ll see the wires that are fed through. The one that has a black and a red wire that would be your travelers and that is going to go to the brass screws and the one that is a black wire and comes from a separate line you know black neutral and ground that’s going to be your common or your load wire. So that’s a really easy way to figure out which wire is supposed to go to the load screw.
Kind of interesting you can look at the wiring in back here to see the separate wire for the travelers the two travelers are on one set of wires and the hot incoming or up going to the light most likely coming from there is on it’s own line there. The neutrals are all shared back there. OK so our hot wire is going to go to the common. For the travelers it doesn’t matter which side goes to which.
For more information on three way light switches check out my video, “Three Way Light Switches How To Change Out Replace Mystery Explained Short Film Video“. That will give more detail.
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