Question about household wiring

Verdinut

Verdinut

Audioholic Spartan
Last edited:
highfigh

highfigh

Seriously, I have no life.
Hey guys, I am replacing a fluorescent overhead kitchen light that quit working.
I assume the ballast went out, but I was kind of looking for an excuse to replace it anyway.

When I apply a multimeter, I get ~36VAC when both of the wall switches are off!
I do get 0V when the circuit breaker is off and 122.5V when the wall switch is on.

So the question is what would cause there to be 36VAC when the wall switches are off?

Is this likely to be the source of failure of the old light fixture (I did try replacing the bulbs, but no luck)?

Miscellaneous:
The new light fixture I plan to install is an Artika Skylight ultra thin LED panel, FWIW. It allows for a dimmable controller, although that will come later if at all. However, I am concerned that 36V may be enough to run the light at a lower level (which would not be a big problem as it would probably make a good night light ... as long as it is safe)!
My house is ~16 years old.
Georgia - Atl. metro area has not invested in hiring more building inspectors as Atlanta has boomed over the past several decades, so don't assume things were done right during construction. If it worked initially, that is all a builder is worried about, the inspection is pretty much a "drive-by".
I have experienced this once before in an older house (50+ years with screw in fuses at the panel), but I did not worry about it after an electrician said it is not uncommon with older homes and if it was him, he would not mess with it. I was replacing overhead light with Ceiling Fan/Light.
As far as my own competence, I am a dude with a Black & Decker Complete Guide to Home Wiring book, but do not see a "Troubleshooting" section. I did successfully install a 240V sub-panel when I got a 240V Powermatic lathe, so I'm good pretty at following directions!

TIA!

Cheers,
Kurt
Did someone make any wiring changes in a nearby junction box? The reason I ask is because I was working on my house and in order to repair the plaster in a hallway, I removed the ceiling light and when I turned the circuit on again, I found that a lot of outlets and switches were dead. A neutral wire had broken in the junction box for that fixture and I didn't know because that box was acting as a hub for too many circuits.

Does that circuit have outlets AND lights, or just lights? Some electricians wire the outlets in parallel and some are in series- If you haven't heard about this, series refers to using one pair of terminals on an outlet for the feed and the other for the outlets farther down the line. If the other outlets are being used, especially by something that uses more power, the strip between one set of terminals and the other becomes a fuse. Parallel refers to twisting the line and downstream wiring, with short pigtails added that go to each outlet. That way, no outlet needs to support the load from others.

I would also check inside of the box where the switch is located- I have seen problems in those, too.
 
Teetertotter?

Teetertotter?

Senior Audioholic
A month ago, we lost the lights in one of our bedrooms and below in the basement, overhead light did not turn on, plus the refrigerator, microwave and airfrier, did not turn on or went out. The circuit breaker did not trip.
A electrician came out to the house and discovered a loose wire in one of the outlet boxes in that bedroom. Within an hour of the electrician arriving, he had it fixed.

My son is the Operations Manager for this rather large electrical contracting firm. The electrician tore up the work order and we were not charged. The electrician came from a job setting up a traffic light in town with a crew. It is winter here in WI. and he was happy to come to our home, at the spur of the moment. lol

Our ranch home was built in 1964. Neutral wires can be common over time.
 
KEW

KEW

Audioholic Overlord
Thermal Imaging won't give you any indication as to voltage levels on any conductor, and won't help you track down you phantom voltage source. Sorry.
Yeah, I didn't expect that it would actually tell me what was happening.
Generally speaking, I would not be willing to do a complete rewire unless it was clear that it was needed to prevent a fire.
So the thermal test would be about ensuring there was not a condition which would result in a fire.
I'm thinking that if there was not a place where the temperature was, say, over 10 degrees above ambient, it is reasonable to leave things be!
 
KEW

KEW

Audioholic Overlord
(Good to see you back here, KEW! I hope you are doing well. Cheers!!!)
Because some of you probably know the tune, my current joy/thrill/happy-place is playing "Well You Needn't" by Theloneus Monk.
It is one of those songs where for the bari. part, I can really throw everything I've got at (not overall volume, but punching the hell out of the attacks on most of the notes)! It is a abdominal workout and great fun!
Well You Needn't by Monk
 
-Jim-

-Jim-

Audioholic General
Yeah, I didn't expect that it would actually tell me what was happening.
Generally speaking, I would not be willing to do a complete rewire unless it was clear that it was needed to prevent a fire.
So the thermal test would be about ensuring there was not a condition which would result in a fire.
I'm thinking that if there was not a place where the temperature was, say, over 10 degrees above ambient, it is reasonable to leave things be!
@KEW

I think you are being over cautious at 10°F above ambient. (I prefer to deal in °C by the way.) Note Ambient is defined as 40°C (104°F) which is plenty warm to begin with. According to a Schnedier / Square D reference which quores UL (United Laboratories Standards):

"The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.
  • Terminations for standard rated breakers: UL 489 Paragraph 7.1.4.2.2 says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (122°F).
  • Terminations for 100% rated breakers: UL489 Paragraph 7.1.4.3.3 says the temperature rise on the termination shall not exceed 60°C (140°F).
  • Handles, knobs, and other user surfaces: UL489 Paragraph 7.1.4.1.6 says the maximum temperature on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on metallic and 85°C (185°F) on nonmetallic surfaces.

Table 1: Summary of temperature rise and maximums for a standard rated breaker (breakers are calibrated in 40 deg. C ambient)
SurfaceTemp. Rise above ambientTemp. Max at 40 deg. C ambient (104 F)
Termination on standard rated breaker50°C (122°F)90°C (194°F)
Termination on 100% rated breaker60°C (140°F)100°C (212°F)
Handles, knobs, other user contact surfaces - MetallicN/A60°C (140°F) Maximum
Handles, knobs, other user contact surfaces - NonmetallicN/A85°C (185°F) Maximum


The heat that is generated from inside the breaker comes from the contacts and the bimetal, which are typically the hottest parts within the breaker, and the temperature in the current path gets cooler the closer to the bus or cable, which function as heat sinks. Therefore, the sides or bottom of the breaker can be hotter than the terminations. Each breaker family or frame will have its own heating characteristics due to different designs. Smaller frames tend to run hotter on the side of the breaker than do larger frames, since the side of the breaker is much closer to the heat generators within the breaker.

If your breaker is operating within the temperature rise and maximum values in Table 1, then the breaker should be operating normally."

Terminations are where the bare conductors are connected to each breaker in the panel.

I hope this is helpful.
 
KEW

KEW

Audioholic Overlord
In homes in Canada, and I'm sure this situation also happens in the US, connections done by hobbyists of the live and the neutral wires are sometimes reversed on outlets. IMO, that is quite more dangerous than any ghost voltage.

A simple tester is a very useful tool:
I have one of those testers and am happy to say that every outlet in my house was good!
 
KEW

KEW

Audioholic Overlord
@KEW

I think you are being over cautious at 10°F above ambient. (I prefer to deal in °C by the way.) Note Ambient is defined as 40°C (104°F) which is plenty warm to begin with. According to a Schnedier / Square D reference which quores UL (United Laboratories Standards):

"The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.
  • Terminations for standard rated breakers: UL 489 Paragraph 7.1.4.2.2 says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (122°F).
  • Terminations for 100% rated breakers: UL489 Paragraph 7.1.4.3.3 says the temperature rise on the termination shall not exceed 60°C (140°F).
  • Handles, knobs, and other user surfaces: UL489 Paragraph 7.1.4.1.6 says the maximum temperature on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on metallic and 85°C (185°F) on nonmetallic surfaces.

Table 1: Summary of temperature rise and maximums for a standard rated breaker (breakers are calibrated in 40 deg. C ambient)
SurfaceTemp. Rise above ambientTemp. Max at 40 deg. C ambient (104 F)
Termination on standard rated breaker50°C (122°F)90°C (194°F)
Termination on 100% rated breaker60°C (140°F)100°C (212°F)
Handles, knobs, other user contact surfaces - MetallicN/A60°C (140°F) Maximum
Handles, knobs, other user contact surfaces - NonmetallicN/A85°C (185°F) Maximum


The heat that is generated from inside the breaker comes from the contacts and the bimetal, which are typically the hottest parts within the breaker, and the temperature in the current path gets cooler the closer to the bus or cable, which function as heat sinks. Therefore, the sides or bottom of the breaker can be hotter than the terminations. Each breaker family or frame will have its own heating characteristics due to different designs. Smaller frames tend to run hotter on the side of the breaker than do larger frames, since the side of the breaker is much closer to the heat generators within the breaker.

If your breaker is operating within the temperature rise and maximum values in Table 1, then the breaker should be operating normally."

Terminations are where the bare conductors are connected to each breaker in the panel.

I hope this is helpful.
Wow!
Thank you so much for providing this, The problem with my plan was not really knowing where the proper threshold would be, but you just gave me a set of established parameters (and where to measure)!
I genuflect in your general direction!
 
KEW

KEW

Audioholic Overlord
Out of curiosity, I measured voltage for a light on a different circuit and it only read 3.2V between the live and common wires.
I'm assuming every circuit has its own "back-story".
 
KEW

KEW

Audioholic Overlord
Thanks!
First I will install it without the dimmer, if for no other reason, so I know where to look if something goes wonky on me.
But, I would not have known that it needs to have specific LED designation!
 
highfigh

highfigh

Seriously, I have no life.
Hey guys, I am replacing a fluorescent overhead kitchen light that quit working.
I assume the ballast went out, but I was kind of looking for an excuse to replace it anyway.

When I apply a multimeter, I get ~36VAC when both of the wall switches are off!
I do get 0V when the circuit breaker is off and 122.5V when the wall switch is on.

So the question is what would cause there to be 36VAC when the wall switches are off?

Miscellaneous:
The new light fixture I plan to install is an Artika Skylight ultra thin LED panel, FWIW. It allows for a dimmable controller, although that will come later if at all. However, I am concerned that 36V may be enough to run the light at a lower level (which would not be a big problem as it would probably make a good night light ... as long as it is safe)!
My house is ~16 years old.
TIA!

Cheers,
Kurt
I saw something about a three way switch arrangement- have you checked the 'traveler' at each switch? If you want to test the fixture, disconnect the wires and cover them with wire nuts, then connect an extension cord to the fixture- if it can work normally, it will. A light fixture can fail, but the ballast usually fails in a way that the voltage to the primary won't be affected. If it shorts, the fuse/breaker should open.

Another test I would do is:

Shut off the breaker
Disconnect the fixture from the wires
Measure the resistance from the hot going to the fixture on the load side of the switch, then measure the resistance on the Neutral, from the switch to the fixture.

If these show almost/no resistance, connect one meter lead to the line side of the switch and the
other to the load terminal- flip the switch and see if you have high resistance.

If you want to skip the last test, you can connect the light's hot and the line wires before energizing the circuit- if the fixture is good, it will work normally.
 
highfigh

highfigh

Seriously, I have no life.
Thanks!
First I will install it without the dimmer, if for no other reason, so I know where to look if something goes wonky on me.
But, I would not have known that it needs to have specific LED designation!
If you pick a dimmer that's not compatible, the light will probably flicker. These work by ramping the voltage on the leading edge or the following edge and that's a major part of the incompatibility.


Many dimmers need some current flow at all times- some timers need this, too.

I recently installed Feit Smart Dimmers and Smart Plugs, so I can schedule turn on/off when I'm not at home. These can be controlled and schedules created using their app and they're far less expensive than Lutron Caseta (I have a few and they're pricey and they need a specific hub if someone wants to control them using something other than their Pico remote). Most smart devices use only the 2.4GHz WiFi band, but they can be set up using BT, if the connection using WiFi doesn't work. I bought the first ones ar Costco, but HD, Ace Hardware and other places sell them, too. The Smart plugs are usually about $10 and the smart dimmers are about $20 each. I even bought a Feit floodlight camera for my garage since the bulbs went out and they're close to ten bucks each- the Feit has LED lights and it was on sale for $99.95, so....
 
panteragstk

panteragstk

Audioholic Warlord
Good to hear from lots of the old gang.
I am actually doing quite well for the most part.
Now that I have had time to heal/adapt from my subdural hematoma, I have realized that my verbal skills have been impacted.
My verbal skills were never great (and I always spoke relatively slowly, but not too much as to be an outlier here in the south).
The good news is that my cognitive skills have not been impacted (that I have noticed). I may be using the wrong words, because verbal skills probably are cognitive, but what I am saying is that thought-wise, I seem to be my old self, but when it comes time to write it down or speak, it can get frustrating. For instance, I probably spent an hour composing my first post in this thread to get all of the i's dotted and t's crossed.
I also run into problems giving commands on the fly, where Alexa does not have enough patience for me because of pregnant pauses in my speech. For example, if I have a command like "Alexa, play Ed Palermo Big Band from Pandora on the downstairs group" I might glitch and pause before "downstairs group" because I don't think in words the way many people do, and I know I want to play the music on "these" speakers so I can walk around without leaving the music behind. However, remembering that "downstairs group" is the proper "code word" for this group can just take too much time unless I mentally rehearse it before I actually say the command.
I need to see if Alexa has a way to increase it's "patience" for me. I am still quicker than some older people (like my grandma in her late 80's and early 90's) so I can imagine that Amazon may allow for such a disability.
But aside from Alexa and the added burden for writing out messages which is a serious penalty on a forum like this, it is pretty much "business as usual". I am still playing Bari Sax in the 3 Big Band Swing Bands and my music performance is on par with what it was before my accident, and that alone gives me a better quality of life than I ever thought I'd have in retirement (not that I was a pessimist, I just loved playing in stage band in HS and never expected to do it again, much less, 3 bands)!
I have no advice on wiring, but I'm glad to hear you're doing OK.

We've missed you around here for sure.
 
KEW

KEW

Audioholic Overlord
I saw something about a three way switch arrangement- have you checked the 'traveler' at each switch? If you want to test the fixture, disconnect the wires and cover them with wire nuts, then connect an extension cord to the fixture- if it can work normally, it will. A light fixture can fail, but the ballast usually fails in a way that the voltage to the primary won't be affected. If it shorts, the fuse/breaker should open.

Another test I would do is:

Shut off the breaker
Disconnect the fixture from the wires
Measure the resistance from the hot going to the fixture on the load side of the switch, then measure the resistance on the Neutral, from the switch to the fixture.

If these show almost/no resistance, connect one meter lead to the line side of the switch and the
other to the load terminal- flip the switch and see if you have high resistance.

If you want to skip the last test, you can connect the light's hot and the line wires before energizing the circuit- if the fixture is good, it will work normally.
Thanks!
This is a good check of the wiring that I had not thought of and it costs nothing other than a little time and finding a wire long enough to run the test - actually I have speaker wires that will cover that.

It will probably be this weekend before I get back to this.
 
Last edited:
KEW

KEW

Audioholic Overlord
Today you can get good imaging equipment for $1500 whereas our gear was well in excess of $20,000.

In a residential panel Thermal Imaging would be looking for a temperature differential typically where conductors are terminated due to a high resistance contact, and / or if a breaker is faulty and overheating. Both are somewhat rare. You could use a Infrared Digital Thermometer with Targeting Laser (cost about $30) which a lot of folks already have in their tool box (I do) if you wanted to look.
Yeah, I have one of the gun/thermometers with a laser, so I will use that.

I don't know what makes imaging equipment qualify as "good", but for infrequent use, you can buy one of these from Amazon for $250. The price seems too cheap, but I don't know how much money is saved by using a phone (or, even better, an 8"-12" tablet) to provide the display and (I assume) conversion from camera output to image. Klein is a company I respect (though they may have been bought or otherwise changed their quality standards for all I know). Thoughts?

Klein Thermal Imaging Camera for Phone/Tablet
 
Verdinut

Verdinut

Audioholic Spartan
Sometimes, just a loose connection between breaker and wire will cause heat and even generate a fire. It may be a safeguard to make sure all connections in the entrance panel are secure. While doing this, it is wise to wear gloves.
 

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