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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7652
Experience:  Proven Professional 48 years Experience
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I have 4 wires in a switch box (not a 3-way) that control 3

Customer Question

I have 4 wires in a switch box (not a 3-way) that control 3 fluorescents. I am unable to figure out what the wires are entirely. I have found the hot/line (confirmed with inductive) which is the white (strange). The ground is obvious because it is an un-sheathed wire. But here's the weird part:
- patch the white & black wires together and the lights turn on, so Black is the load wire (also confirmed with a meter that shows 125v between white to black).
- The Red, however, is the issue. White to Red shows 69v on the meter, but tying them together does nothing.
- Red to Black shows 20v (note that is Twenty Volts), as does Red to Ground.
What is the red wire? I'm trying to install an insteon switch and having identified line and load I assumed that the red what neutral, but it apparently is not.
Submitted: 11 months ago.
Category: Electrical
Expert:  Mike G. replied 11 months ago.

Hi, I'm Mike and I'll be assisting you. Please stand by while I review your question.

Expert:  Mike G. replied 11 months ago.

When a 2 wire cable is used for switch leg the white is the hot and should have black tape to identify it being used as a hot. The black would then be the switched hot to the fixture. A non used red indicates that you have a midwife. Go to the fixture the 3 wire originates from to make the corrections Tell me what the count and colors are and I'll give you instructions.