Voltage fluctuation giving me the blues.
January 25, 2018 2:48 PM Subscribe
The lights in my home office have been flickering like strobes in a 1970s disco. I pulled the switch, and now the wires that connected to it are dead, reading 0 on a voltage meter. What's going on?
My home office is illuminated by 60 watt bulbs in four cans connected to a dimmer switch. Over the past year, the voltage to the lights has fluctuated, with the lights flickering at random times (ie, independent of voltage loads on other appliances in the house).
The problem worsened recently, and I pulled the dimmer switch to see if replacing it would solve the problem. At that point, I lost power to the wires connecting to the switch, which read zero volts now on my voltage meter.
The receptacles, oddly, aren't affected, unless I cut power to them at the breaker. When I restore power at the breaker, the receptacles come back on, but no volts feed into the wires at the box for the dimmer switch.
Is it possible that the breaker is faulty? I don't have a problem with replacing it, even as part of a trouble shooting procedure.
Or, could something else be going on?
My home office is illuminated by 60 watt bulbs in four cans connected to a dimmer switch. Over the past year, the voltage to the lights has fluctuated, with the lights flickering at random times (ie, independent of voltage loads on other appliances in the house).
The problem worsened recently, and I pulled the dimmer switch to see if replacing it would solve the problem. At that point, I lost power to the wires connecting to the switch, which read zero volts now on my voltage meter.
The receptacles, oddly, aren't affected, unless I cut power to them at the breaker. When I restore power at the breaker, the receptacles come back on, but no volts feed into the wires at the box for the dimmer switch.
Is it possible that the breaker is faulty? I don't have a problem with replacing it, even as part of a trouble shooting procedure.
Or, could something else be going on?
I don't see how the breaker could be the problem, if the lights and receptacles are on the same breaker. Where I live, though, they usually aren't. Do you have some way to double-check that? Also, do you know where in the circuit the dimmer switch is (I mean, does it go breaker -> dimmer -> can -> etc. or something else), and can you check voltage at the cans?
Could you be not measuring what you think you're measuring (like, maybe you're measuring across the dimmer switch by accident)? You say "now", but did you ever have a voltage reading on these same wires?
I mention measurement error because I've made plenty, not to cast aspersions on your troubleshooting!
posted by inexorably_forward at 3:45 PM on January 25, 2018 [1 favorite]
Could you be not measuring what you think you're measuring (like, maybe you're measuring across the dimmer switch by accident)? You say "now", but did you ever have a voltage reading on these same wires?
I mention measurement error because I've made plenty, not to cast aspersions on your troubleshooting!
posted by inexorably_forward at 3:45 PM on January 25, 2018 [1 favorite]
Are you measuring AC voltage? DC would give you incorrect info, but should give something I think.
posted by TheAdamist at 3:57 PM on January 25, 2018
posted by TheAdamist at 3:57 PM on January 25, 2018
what are you referencing for your voltage reading at the dimmer?
posted by Dr. Twist at 4:30 PM on January 25, 2018
posted by Dr. Twist at 4:30 PM on January 25, 2018
It's pretty common practice to put lights on one breaker and receps on another. That way the room is not completely out of power if one circuit or the other fouls up. You could use a floor lamp to change out a overhead light switch for example.
posted by rudd135 at 5:33 PM on January 25, 2018
posted by rudd135 at 5:33 PM on January 25, 2018
Did you check for a tripped breaker? It's not always obvious from looking at them. But the lights are on a different breaker than the receptacles.
Are either of the wires that used to go to the dimmer joined with other wires in wire nuts? It's possible a wire came loose from such a joint and got worse over time due to arcing and vibration, and maybe came loose completely when you pulled the dimmer.
If you're not comfortable troubleshooting this you should call an electrician if you own, or the landlord if you rent.
posted by under_petticoat_rule at 7:06 PM on January 25, 2018 [2 favorites]
Are either of the wires that used to go to the dimmer joined with other wires in wire nuts? It's possible a wire came loose from such a joint and got worse over time due to arcing and vibration, and maybe came loose completely when you pulled the dimmer.
If you're not comfortable troubleshooting this you should call an electrician if you own, or the landlord if you rent.
posted by under_petticoat_rule at 7:06 PM on January 25, 2018 [2 favorites]
Although there are many possible explanations, the one that first occurred to me is the one under_petticoat_rule suggested: there was a bad connection somewhere in the light circuit, and pulling the dimmer jostled it enough to break it entirely. This is consistent with the flickering, unrelated to the load, and with the sudden disconnect. And it is not only normal but good practice for lights and receptacles to be on separate circuits. That the lights are recessed (in cans) suggests that the wiring is pretty recent, which makes separate breakers seem even more likely.
At this point, even I (who have done a lot of my own wiring in my day) would probably turn it over to an electrician.
posted by mr vino at 7:25 PM on January 25, 2018 [2 favorites]
At this point, even I (who have done a lot of my own wiring in my day) would probably turn it over to an electrician.
posted by mr vino at 7:25 PM on January 25, 2018 [2 favorites]
How many cables do you have coming into the box holding the dimmer? How many wires in each of the cables and what colour are they?
When you say there is no voltage at the switch how are you measuring and have you removed the switch from the circuit. I'd check the voltage between each of the insulated wires and the bare wire. I'd then check the voltage across the switch if it is still in the circuit. If all those test give you a 0V reading then your problem is with the power coming into the switch.
If you are lucky that'll be a loose splice. If you are a little unlucky it'll be the connection at the breaker. And if you are really unlucky it'll be a hidden splice or a damaged cable.
Cans have been around commonly since the 70s and of course could have be retrofitted to a much older building so they don't really indicate an age all by themselves.
There are many pros and cons for combining lights and receptacles or keeping them separate and it is pretty common to see both methods even in the same house IME. It would be pretty unusual to have a circuit only servicing 4 pot lights though.
Breakers don't usually work intermittently so I doubt that is your issue. It could however be a loose connection at the breaker or anywhere else upstream of the lights in the circuit.
posted by Mitheral at 8:51 PM on January 25, 2018
When you say there is no voltage at the switch how are you measuring and have you removed the switch from the circuit. I'd check the voltage between each of the insulated wires and the bare wire. I'd then check the voltage across the switch if it is still in the circuit. If all those test give you a 0V reading then your problem is with the power coming into the switch.
If you are lucky that'll be a loose splice. If you are a little unlucky it'll be the connection at the breaker. And if you are really unlucky it'll be a hidden splice or a damaged cable.
Cans have been around commonly since the 70s and of course could have be retrofitted to a much older building so they don't really indicate an age all by themselves.
There are many pros and cons for combining lights and receptacles or keeping them separate and it is pretty common to see both methods even in the same house IME. It would be pretty unusual to have a circuit only servicing 4 pot lights though.
Breakers don't usually work intermittently so I doubt that is your issue. It could however be a loose connection at the breaker or anywhere else upstream of the lights in the circuit.
posted by Mitheral at 8:51 PM on January 25, 2018
Actually, this sounds like a 3 way switch problem. You should have a power lead, a neutral lead and a ground lead. If there are extra wires hanging around the previous system may have a 2nd switch affecting the lights. There are too many links to include one that makes sense in this situation. You might include a simple diagram (indicating color of wire) to give us some insight into your situation.
posted by ptm at 2:29 PM on January 26, 2018
posted by ptm at 2:29 PM on January 26, 2018
This thread is closed to new comments.
posted by coldhotel at 3:38 PM on January 25, 2018