feralferret
Veteran Member
This definitely sounds like an open neutral problem. There is likely a junction where several neutral wires are connected. The neutral normally does NOT run through the switch box.
…… Home electrical advice needed - bathroom exhaust fan
- Thread starter Slydersan
- Start date
BornFree
Came This Far
This is why they make volt meters. So that people can diagnose problems more quickly without going through so much trouble. Since there is newer wiring then I assume there are ground wires. So remember that the Neutral and ground are connected back at the breaker box. There should be no voltage measured between them. Also measure between the hot supply line(Power supplying switch) and both neutral and ground. If you get a reading from the ground, but not the neutral then you have and open neutral. No reading either way would say that you probably have an open hot.
Check the output from the switch next if the previous checks are good. Then at the light wiring next if you don't find a problem.
Here is a very common problem. If there is an outlet on the same circuit then the power wire to your light circuit might run through it. It was a common practice to use the stab connectors in the back of the outlet to make connections(Instead of using the screws) Those stab connections often fail in time. If one fails on the input side of the outlet then the outlet will also not work. But it it fails on the output side of the outlet than the outlet will work fine, but not anything after the outlet. So you need to pull out the outlet and inspect or replace. If you had your light turned on and then you wiggle the wires on the back of the outlet then the light might flicker on. Also check any wire capped connections for lose wires.
Warning: there is risk of shock if you work with a live circuit so don't do it unless you are safely secure in doing so.
Check the output from the switch next if the previous checks are good. Then at the light wiring next if you don't find a problem.
Here is a very common problem. If there is an outlet on the same circuit then the power wire to your light circuit might run through it. It was a common practice to use the stab connectors in the back of the outlet to make connections(Instead of using the screws) Those stab connections often fail in time. If one fails on the input side of the outlet then the outlet will also not work. But it it fails on the output side of the outlet than the outlet will work fine, but not anything after the outlet. So you need to pull out the outlet and inspect or replace. If you had your light turned on and then you wiggle the wires on the back of the outlet then the light might flicker on. Also check any wire capped connections for lose wires.
Warning: there is risk of shock if you work with a live circuit so don't do it unless you are safely secure in doing so.
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mistaken1
Has No Life - Lives on TB
When troubleshooting unknown wiring I always get paper and a pencil and start making diagrams of what I find in each junction box, switch and outlet. If I haven't solved the problem doing what others have wisely suggested (check every connection) then it is time to kill power, separate connections and start mapping wires between boxes using continuity checks.
Last time I checked the NEC feeding through devices is not permitted, the wires should be spliced in the box with a pig tail feeding the device. Lazy house wiremen love them their stab connectors and wire that extends outside the box just enough to stick it in the back of the device.
Ever open a box to find a dozen wires all to short to actually work with once the initial crappy install has failed?
I have had some so short I could not even get the plug out of the box. All you can do then is kill the power and splice extensions onto the short wires so a new plug can be installed.
Electric smoker on the patio .... outlet in the house over 100 degrees according to the IR thermometer .... you guessed it, crappy stab connectors feeding through that inside outlet to the outside patio outlet, the current draw from the smoker was heating up the high resistance connections in that inside outlet to the point of house fire here we come.
Just because some monkey boy calls himself an E Lek Trish Ian does not mean they have clue what they are doing. Last year he was a dump truck driver in Tennessee, this year he is an electrician in Kansas and next year he will be a plumber in Colorado.
Last time I checked the NEC feeding through devices is not permitted, the wires should be spliced in the box with a pig tail feeding the device. Lazy house wiremen love them their stab connectors and wire that extends outside the box just enough to stick it in the back of the device.
Ever open a box to find a dozen wires all to short to actually work with once the initial crappy install has failed?
I have had some so short I could not even get the plug out of the box. All you can do then is kill the power and splice extensions onto the short wires so a new plug can be installed.
Electric smoker on the patio .... outlet in the house over 100 degrees according to the IR thermometer .... you guessed it, crappy stab connectors feeding through that inside outlet to the outside patio outlet, the current draw from the smoker was heating up the high resistance connections in that inside outlet to the point of house fire here we come.
Just because some monkey boy calls himself an E Lek Trish Ian does not mean they have clue what they are doing. Last year he was a dump truck driver in Tennessee, this year he is an electrician in Kansas and next year he will be a plumber in Colorado.
I keep a book of these stuck in my truck console.
Number, letters and a picture...saves some guessing.
They don't bite that well, a little wrap of clear tape helps.
Number, letters and a picture...saves some guessing.
They don't bite that well, a little wrap of clear tape helps.
mistaken1
Has No Life - Lives on TB
Isn't it amazing that those have been around forever yet they still don't stick worth a crud?
dawgofwar10
Veteran Member
They sure do, thats why I don't play with electricty anymore.
Repairman-Jack
Veteran Member
Depends on year built and NEC codes in place at time. I believe post 2011 neutrals are required in the switchbox with a few exceptions.
Repairman-Jack
Veteran Member
Daisy chaining through devices is permitted, so long as the device is rated..most receptacles and switches are rated.
mistaken1
Has No Life - Lives on TB
True as long as it not a multi-wire branch circuit.
Section 300.13b in the code, which states: “In multi-wire branch circuits, the continuity of the grounded (neutral) conductor shall not depend on device connections such as lamp holders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.” There is similar wording for the grounding conductor.
No requirement for the 'hot' conductor to pigtail. But doing it for the grounding conductor and grounded conductor may as well do it for the 'hot' conductor. All my work as a commercial electrician involved multi-wire branch circuits so pigtailing (parallel) is just a habit for me.
mistaken1
Has No Life - Lives on TB
Could be the fan/light was fed from the load side of a GFCI outlet.
I had one friend who lost some kitchen outlets (no power) turns out they were fed from the load side of a GFCI outlet in the guest bathroom (shared a wall with the kitchen). No one used the outlet in the guest bathroom so they did not realize it was tripped.
feralferret
Veteran Member
Thanks for the info. My last job that required me to be involved with wiring ended in 1996, so I am a little behind on code changes.
TidesofTruth
Veteran Member
Tons of good advice here. I would only add, If you do have 110/120V with a meter and you do have a good neutral with no voltage to ground, there still could be an issue with connection that would only show up under load. This is harder to detect but then I would be very cautious with any electricity on the circuit being on until the problem is diagnosed. You do not want a poorly jumpered or poor connection throwing sparks in the wall.
Here's an update.... nothing changed. LOL
I spent a few hours looking at this again today. I traced the wire from the panel to the switch. Even took the panel cover off and made sure all the connectors were in place and no little beastie had made a home inside it- everything was fine. It honestly doesn't even look like anything else is on this circuit. The fan was probably installed when all of the 80's renovations was done and it looks like they literally created a new circuit for this fan. So it's not connected to any GFCI outlet at all. I checked the few GFCI outlets that I have anyways and all were fine. I tested continuity from the switch to the fan connectors - all good. Checked the voltage at different places - all good. I swapped out the switch with a different one - no difference. I checked the little outlets in the fan housing - they all were fine, continuity good, etc.
So at this point I give up. I've spent too much time on this already, so I'm breaking down and calling a pro. I'll try and update with what the problem was when I get someone out here.
I spent a few hours looking at this again today. I traced the wire from the panel to the switch. Even took the panel cover off and made sure all the connectors were in place and no little beastie had made a home inside it- everything was fine. It honestly doesn't even look like anything else is on this circuit. The fan was probably installed when all of the 80's renovations was done and it looks like they literally created a new circuit for this fan. So it's not connected to any GFCI outlet at all. I checked the few GFCI outlets that I have anyways and all were fine. I tested continuity from the switch to the fan connectors - all good. Checked the voltage at different places - all good. I swapped out the switch with a different one - no difference. I checked the little outlets in the fan housing - they all were fine, continuity good, etc.
So at this point I give up. I've spent too much time on this already, so I'm breaking down and calling a pro. I'll try and update with what the problem was when I get someone out here.
Honestly, one can troubleshoot this in about ten minutes. Have fun.
Knoxville's Joker
Has No Life - Lives on TB
Also if possible get one of those scope cans and check for surprises in the wall. Might be able to run a whole new wire to the fan if lucky…
Finally had an electrician out today. Long story short it was due to low voltage on that circuit. So hat's off to everyone who called that. Turns out the tool I used to diagnose the problem is very low tech and rudimentary. It checks for something in the 110volt range... or in the 12v range, not anything specific. Electric-dude said it was right around 100volts. So while my meter read it as "correct", it wasn't "correct enough." LOL
Another light in the bathroom is actually on a different circuit, so instead of spending another chunk of money for him to diagnose the low voltage problem, etc etc. He just tapped the other (good) circuit and installed the fan and all is good.
I asked about dangers/issues/causes. He said there is no danger, if it was grounding out or a mouse chewed on it or something the circuit breaker would trip. Cause could be something like brittle/old wires (which is possible I guess, this house is old), or something like a loose ground wire. Looking back I should have probably noticed the low voltage thing because that switch is one of the ones that glows orange when off (so you can see it in the dark) and it was very dim. But now it's bright as it should be.
Thanks to everyone who offered help and suggestions.
Another light in the bathroom is actually on a different circuit, so instead of spending another chunk of money for him to diagnose the low voltage problem, etc etc. He just tapped the other (good) circuit and installed the fan and all is good.
I asked about dangers/issues/causes. He said there is no danger, if it was grounding out or a mouse chewed on it or something the circuit breaker would trip. Cause could be something like brittle/old wires (which is possible I guess, this house is old), or something like a loose ground wire. Looking back I should have probably noticed the low voltage thing because that switch is one of the ones that glows orange when off (so you can see it in the dark) and it was very dim. But now it's bright as it should be.
Thanks to everyone who offered help and suggestions.
