Four-way switches

Hi All,

One of the practice exams mentions using 3 four-way switches to control the same group of lights. However, my understanding is that a four-way switch can be used to connect 2 three-way switches but I can’t understand how 3 four-way switches would work when grouped together. I think the 2 four-way switches on either end would have 1 redundant common connector.

This is my resource:

If there is a better resource to understand why we would use 3 four-way switches could you please share?


Hi @clent - your understanding is correct, but I think you’re overthinking it for the purposes of the ARE. I love watching these kinds of videos for my own knowledge, but I’d say this is geared more towards an electrician than an architect. A few important things to note:

  • While two of these four-way switches will have an unused terminal, that’s fine. In fact, you could wire all of your switches using 3-way switches (if you wanted to waste money) - it’s the same concept. An unused terminal isn’t an issue.

  • Typically on an architectural RCP of a four-way switch, each of the switches has a number 4 next to it. That’s as far as the architect takes it - it’s up to the electrician after that if they want to use one four-way switch and two three-way switches. In my opinion, getting into further detail than that on an architectural set of drawings turns it into more of a wiring diagram, and is getting into the contractor’s means and methods.

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