My wife asked me to replace a switch in her room because the ancient ceiling light was not working. The house is over 90 years old. The wiring for the switch had fabric insulation, which is easy to crumble. I removed the switch plate and found the switch had been screwed into something, but it wasn't a box and there was plaster from the walls around it. The wires were solid. There were only two, no ground wire. One had white fabric insulation and the other black. I connected these to a new Lutron switch. After securing the wires, when I turned on the switch the ceiling light did not work. I brought a voltage meter to bear on the situation. I was only reading 71 volts across the circuit. What does this mean? Is there a short in the circuit somewhere - possibly in the ancient ceiling light fixture?
1
-
1I'm guessing that the "71 volts" is actually an open circuit where the full voltage is being capacitively coupled to the wires. There's enough power to make the voltmeter read something, but not enough to make the light light.– Daniel GriscomCommented Dec 14, 2015 at 1:31
Add a comment
|
2 Answers
Well as you said the light was not working in the first place. Replacing the switch apparently wasn't the problem. Your next step would be to investigate the light fixture itself.
What type of light fixture is it? Flourescent, compact flourescent, LED?
When you say "71 volts across the circuit", do you mean across the switch? When it is on or off?
We need more information to help you.
Happy Sunday!
answered Dec 13, 2015 at 18:33
What you have is a switch loop. Just a hot wire coming down to the switch and a switched wire going to the light. If you take a reading across these two wires you will not get any kind of useful reading since you are reading the voltage through the load, not to a clean ground or neutral source.
What switch did you install? Does it require a neutral?
answered Jan 13, 2016 at 12:14
