Electrical – run a new independently-switched light from a box in a four-way switch circuit

electricaljunction-boxlight-fixturewiring

I'm doing some renovating and where I want to put a closet I'd like to put a light. There is a junction box there which appears to have been used as a light before and would be ideal. It has only 1 3-wire coming in and 1 out, twisted together. They moved the light elsewhere. I'm hoping I can use this box for a light with its own switch and somehow get power from it.

So the current configuration goes like this:

 Light 
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Switch 1
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 J-box (old light box?)
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Switch 2
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Switch 3 (power)

2-wire from the light to the first switch. 3-wire from that switch to the junction box and 3-wire to 2 other switches. Power comes in at Switch 3. Can I get power from this box or do I have to use a new line?

Best Answer

You do not have enough conductors in those cables to add a constantly powered device at the j-box. You would have to either run another wire from switch 1 to the j-box, or abandon the use of switches 2 and 3 and control the existing light with switch 1 only.