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?
Electrical – Measuring only 71 volts at light switch
electrical
Related Solutions
From what you've described, this is what I think you're wiring should look like. Keep in mind, this is just a guess. I can't see what's going on, and I'm an internet away, so I can't touch/measure/test anything.
The wiring diagram for the switch, can be found in the installation instructions.
If you provide images, and/or a better description of what wires and cables are in each box. I'll be able to provide a better guess, as to how this should be wired.
NOTE:
The diagram is based on your description, and is my best guess as to what your wiring looks like. If you're not sure what to do, or feel like this project is over your head. Do not hesitate to contact a local licensed Electrician.
This, thankfully, is simple. The black wire in that outgoing cable to the fan connects to the fan and the red wire connects to the light -- so you simply have to pigtail the black and red wires together with a wirenut and a short length of wire, and connect the pigtail to the switch terminal. That will give you simultaneous control over the light and fan from that switch, while leaving your options open to install a double switch or fan controller later.
Best Answer
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!