LIght switches getting hot

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Re: LIght switches getting hot

314.17(B)
the last sentence in the paragraph:
Where raceway or CABLE is installed with metal boxes or conduit bodies, the raceway or cable shall be secured to such boxes and conduit bodies.

Beachbum
most of us older ... ah, I mean experienced guys, will tell you that sidework is not the way to learn this business. You are not experienced enough, and if this person is a friend you are not doing them a favor. You may not see other problems with this installation that may exist, and therefore a more experienced individual would spot it.
Good luck though, and stay at it in our great industry!!!
 
Re: LIght switches getting hot

Originally posted by peter d:
The 96 volts you read with your DMM is probably a ghost voltage and can be ignored.
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From everything I've read about ghost voltage, a conductor may impress a voltage on another which may have no voltage giving an inaccurate reading. Nowhere did I read that the ghost voltage could affect it's own circuit. Is this information from years of experience? Do you know of any place were I could find more information on this. I want to learn as much as possible.
 
Re: LIght switches getting hot

Jeremy,

I'm not quite sure what you're asking but a ghost voltage can pop up in just about any situation where you use a DMM. Yes, I have learned this from doing a lot of troubleshooting.

As my former instructor in school told me, when it comes to troubleshooting, "The devil is in the details." There are many subtle issues of troubleshooting that can't be conveyed or taught over a computer screen. They can only be demonstrated in a real life situation or a training lab with an experienced electrician or instuctor at the helm. I'm not trying to discourage you, but rather to encourage you to enroll in an apprenticeship program or electrical courses if you haven't allready done so.
 
Re: LIght switches getting hot

I am in a program and classes, but when learning baout meters, nothing was explained to use about ghost voltage, not have I heard anything aout it in the filed.
 
Re: LIght switches getting hot

Originally posted by beachbumjeremy:
I am in a program and classes, but when learning baout meters, nothing was explained to use about ghost voltage, not have I heard anything aout it in the filed.
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That is a shame. They glossed over a very important topic in my opinion. Shame on them. :mad:
 
Re: LIght switches getting hot

Take your voltage reading at the track feed from H-G and H-N with the hot and switchleg wirenutted together in the switch box. DO NOT TEST with the dimmer in the circuit. Test with the wires terminated to the track feed and test with the wires removed from the track feed. This will tell you if there's a problem with the track. I have a feeling that it's a dimmer heating problem.

Count up the wattage of the lamps in the track and make sure they don't exceed the dimmer wattage. Dimmers do get hot and they should be derated, as mentioned earlier in this post, because they're in the same box side by each.
 
Re: LIght switches getting hot

BBJ if you are reading from hot to switch leg and getting 96 volts that is not ghost voltage it is reading through the bulbs on the track light,Test at definitive points using the neutral and double check against ground.You can`t get an answer trying to read through a circuit,you have to read off points of origin,switch,lamp holder etc.You are trying to test in series that won`t work for what you are testing for.
Series troubleshooting is a whole new chapter ;)
 
Re: LIght switches getting hot

When a voltmeter has an extremely high input impedance, the amount of energy needed for the voltmeter to determine a reading is very small.

So small, in fact, that a capacitive charge on a floating length of wire in, say, a cable, will not be depleted by the voltmeter taking what energy it needs to make a reading. In this case, the very high input impedance meter actually measures the voltage across itself as the charge on the wire travels through the sensing circuit. This is "ghost voltage".

A voltmeter with a mechanical movement has a much lower input impedance than a DMM. So much so, that connecting the lead of the mechanical voltmeter effectively drains away the charge on the floating conductor, and reports a voltage of zero.
 
Re: LIght switches getting hot

Originally posted by allenwayne:
BBJ if you are reading from hot to switch leg and getting 96 volts that is not ghost voltage it is reading through the bulbs on the track light.
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Allen, with the dimmer removed, testing from hot to switched hot, he should get a reading of 120 volts, and this is assuming that all the bulbs in the track are good. ALL of the circuit voltage appears across an open (assuming only one open is in the circuit).

I highly doubt that the current that a Wiggy draws is enough to cause a significant voltage drop across the filaments of the bulbs. Certainly not 24 volts.
 
Re: LIght switches getting hot

Originally posted by al hildenbrand:
When a voltmeter has an extremely high input impedance, the amount of energy needed for the voltmeter to determine a reading is very small.

So small, in fact, that a capacitive charge on a floating length of wire in, say, a cable, will not be depleted by the voltmeter taking what energy it needs to make a reading. In this case, the very high input impedance meter actually measures the voltage across itself as the charge on the wire travels through the sensing circuit. This is "ghost voltage".

A voltmeter with a mechanical movement has a much lower input impedance than a DMM. So much so, that connecting the lead of the mechanical voltmeter effectively drains away the charge on the floating conductor, and reports a voltage of zero.
Click to expand...
Does this mean what JBWhIte said is correct..."the ghost voltage should not be present when the circuit is energized. "
Is this always true?
 
Re: LIght switches getting hot

You can read a ghost voltage on an energized circuit. In fact, we did this in my class once.

We plugged one lead of the DMM into an outlet, and then we took turns grabbing the other lead of the DMM and touching the dry erase board. By expanding the area of the plate of the capacitor (the board,) we were able to get a reading of well over 100 volts.
 
Re: LIght switches getting hot

let me correct my own statement.

with the circuit energized, the ghost can still be present, but the effect is so minimized that the point is mute regarding 120v power wireing.

120.08v vers 120.90v who cares.

if you are dropping all the way down to 96 volts. there is another problem. purhaps as mentioned above, the dimmer causing the readings to be off, or trying to test in series instead of parallel to the voltage.

if you get 120v phase to neutral and 96 phase to ground, then you have a problem with the main bonding jumper.
 
Re: LIght switches getting hot

Originally posted by peter d:
You can read a ghost voltage on an energized circuit. In fact, we did this in my class once.

We plugged one lead of the DMM into an outlet, and then we took turns grabbing the other lead of the DMM and touching the dry erase board. By expanding the area of the plate of the capacitor (the board,) we were able to get a reading of well over 100 volts.
Click to expand...
was your dry erase chalk board connected in any way to the system neutral, or system ground.??
 
Re: LIght switches getting hot

I really think some of you are making this more complicated than it has to be.

Saying that that 96 volts means this or that is bad advice in my opinion. I think it's a ghost voltage, nothing less, nothing more, and probably can be ignored for the sake of this discussion.

The only way to know for sure is to use a Wiggy and test ACROSS the switch, that is check between the hot and switched hot with the device removed. There should be 120 volts. If there isn't, there is an open present somewhere else in the circuit.
 
Re: LIght switches getting hot

Originally posted by jbwhite:
was your dry erase chalk board connected in any way to the system neutral, or system ground.??
Click to expand...
No, it doesn't have to be. Remember, ghost voltage, as Al explained is caused by capacitance.

A capacitor = two plates separated by an inuslator. In the case of the dry erase board, the dry erase board was one huge plate, next to another huge plate, the concrete floor, which is connected to the building GES.

Current does not flow through a capacitor in an AC system, but flows from one plate to the other as the polarity changes. This gives the appearance of current flow.
 
Re: LIght switches getting hot

Originally posted by beachbumjeremy:
Does this mean what JBWhIte said is correct..."the ghost voltage should not be present when the circuit is energized. "
Is this always true?
Click to expand...
No, its not always true, as Peter is pointing out. The important nub, in my opinion, is "the very high input impedance meter actually measures the voltage across itself as the charge on the wire travels through the sensing circuit."

As Peter illustrated, in his class they created a capacitor on one lead of the DMM, and attached it to an energized source. In the right relationship, the capacitor limits the energy that moves through the DMM, so it reports a reading that is not accurate.
 
Re: LIght switches getting hot

peter d, i conceed on the ghost voltage being possible with the circuit energized.

I disagree with your troubleshooting technique.

I would remove the dimmer and replace with a toggle switch. test voltage hot to neutral, and hot to ground at the panel, switch, and socket to determine where the fault is occuring.

Testing from line side of sw to load side of sw with sw off or removed will only tell you if the problem is from the source or not. it will not narrrow down what component is causing the problem.
 
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