Should I have voltage on my earth ground?

[tlmartin84]

I have 12 lights wire in parallel off of a switch.

Today I unhooked the ground wire NOT the neutral....... and I got a little jolt out of it.

When I hooked it back up, no voltage on it. I was expecting there to be no voltage when unhooked. I can stand there and hold it in one hand and my tester lights up in the other hand. Doesn't shock me until I touch something else.

 

[NJ20]

I'm not an electrician but I do not think you should have voltage on your earth ground. Something can't be right. How many volts are you measuring? Maybe some type of stray voltage.

 

[malibu101]

Where in the circuit did you disconnect the ground?
Was the circuit turned on or off when you disconnected the ground?

No matter what though, that is obviously not right.

 

[justsam]

A voltage indicator light is not going to cut it. Get even a cheap Digital Voltmeter. Harbor Freight even gives them away at times.

Measure voltage between ground and neutral, should be near zero.

Measure voltage between hot and neutral, should be 120VAC.

Measure voltage between ground and hot, should also be 120VAC.

If this circuit is fed from main panel, need to confirm that ground and neutral are firmly bonded together at main panel. Voltage between ground and neutral bar should be zero at panel.

 

[tlmartin84]

I disconnected it between the panel and switch..... the neutral and hot were connected and on. When I killed the light switch the Ground was dead.

 

[tlmartin84]

If this circuit is fed from main panel, need to confirm that ground and neutral are firmly bonded together at main panel. Voltage between ground and neutral bar should be zero at panel.

Is the fact that I disconnected it between the panel and switch the problem?

Once it was connected both the ground and neutral showed nothing, only thing that read hot was the hot.

I'll check it tomorrow with the multimeter.

 

[LS6 Tommy]

You got shocked with the ground disconnected at the breaker panel? Sounds like something on that switch is sharing a neutral and a ground or is using ground as a neutral...

Tommy

 

[tlmartin84]

One other thing, these lights are 120V or 240V, the ballast says you can wire them either way.

I have them on 120V, any chance that they are returning voltage through the ground like a 240V circuit would and essentially not using the neutral as a return?

 

[Pwrgeek]

How long is the run back to the panel? You can get some induced voltage in a wire that is near one that is energized based on how far they run together. This would point to that circuits group wire not being tight in the ground bar at the main panel.


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[wyliesdiesels]

One other thing, these lights are 120V or 240V, the ballast says you can wire them either way.

I have them on 120V, any chance that they are returning voltage through the ground like a 240V circuit would and essentially not using the neutral as a return?

A ballast doesnt even connect to ground through the leads.

If the ballast was using the EGC it would be through the ballast case which would mean theres a short to the frame.

A more probable scenario is that someone is using the EGC as a neutral.

 

[tlmartin84]

A ballast doesnt even connect to ground through the leads.

If the ballast was using the EGC it would be through the ballast case which would mean theres a short to the frame.

A more probable scenario is that someone is using the EGC as a neutral.

I just wired them so I know thats not the case.

I have these lights hooked up at my main panel(meter base with exterior breakers). This was temporary so I had light while running the rest of wiring. In effort to leave them on as long as possible I cut the ground wire close to the sub panel and attempted to feed it through a romex connector. Thats when I got lit up, when Ihad a hold of it, and grounded myself touching the box. I, like most of you dont think there should be power here though. I flipped the switch and continued with no issues.

Was I getting backfed through the neutral at the panel box where it bonded?

 

[tlmartin84]

Or the only other possibility is a short somewhere.....i cant imagine one. But maybe there is.

 

[LS6 Tommy]

The only scenario I can see where you can get shocked when touching the panel and the disconnected ground of the circuit is if the circuit your touching is "sharing" a neutral with a ground, a device has current "leakage" or using ground as a neutral.

Tommy

 

[tlmartin84]

OK, checked it with my multimeter..... at the very last light.

Ground - Neutral. 2.9V
Ground - Hot. 120V
Neutral - Hot. 117V

Any verdicts???

 

[tlmartin84]

How long is the run back to the panel? You can get some induced voltage in a wire that is near one that is energized based on how far they run together. This would point to that circuits group wire not being tight in the ground bar at the main panel.


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150' is that enough to draw 3 volts?

 

[theoldwizard1]

Every homeowner should own 3 AC electrical test tool. A polarity/ground/neutral test plug (plug it in and look at the lights), a non-contacting voltage detector and some kind of DMM even if is the HF "freebie" !

 

[iron block]

tlm -

1. "Today I unhooked the ground wire NOT the neutral....... and I got a little jolt out of it. " Can you measure the voltage at this point, between the ground wire you unhooked and the point at which it was formerly connected?

In other words, how big a jolt did you get?

2. "One other thing, these lights are 120V or 240V, the ballast says you can wire them either way." Are these electronic ballasts? If so, I wonder if they have some sort of internal EMI filter that bypasses hot and neutral to case ground through small capacitors -- that sort of thing can raise the potential of the case when the ground lead is lifted.

 

[larry_g]

Another data point, what current flowing in the ground wire? That will tell you a lot. No current but voltage then probably induced. A measurable amount of current then leakage or miss wired.

lg
no neat sig line

 

[justsam]

OK, checked it with my multimeter..... at the very last light.

Ground - Neutral. 2.9V
Ground - Hot. 120V
Neutral - Hot. 117V

Any verdicts???

So I am not sure what you got zapped with in the first post. If it was between ground and neutral that looks like 3 VAC. Not much of a jolt.

Check at the panel and see if you see this same potential between the ground and neutral bars. I continue to think they are not bonded.

 

[tlmartin84]

Another data point, what current flowing in the ground wire? That will tell you a lot. No current but voltage then probably induced. A measurable amount of current then leakage or miss wired.

lg
no neat sig line

What do you mean by induced?

 

[tlmartin84]

So I am not sure what you got zapped with in the first post. If it was between ground and neutral that looks like 3 VAC. Not much of a jolt.

Check at the panel and see if you see this same potential between the ground and neutral bars. I continue to think they are not bonded.

It feels about like sticking a 9 volt battery on your tongue. Doesn't hurt but I still don't like the feeling.

Everything is bonded properly I am sure of that.

I checked most of my circuits, the only ones showing the voltage reading across the neutral and ground are the ones with the fluorescent lights. All other light and outlet circuits read zero across the neutral and ground.

FYI the more fluorescent lights on a circuit, the higher the voltage reading.

I think that it has to be something with the ballasts.............

 

[onthefence777]

Surprised no one has said this yet.

You worked on an energized circuit?

Without turning the breaker off?

Even when working on a car, I always remove the ground connection last.

 

[larry_g]

What do you mean by induced?

Two wires running close, one powered with AC, will 'induce' a voltage in the other one. A transformer is a prime example of one wire 'inducing' power into another.

lg
no neat sig line

 

[Pwrgeek]

It feels about like sticking a 9 volt battery on your tongue. Doesn't hurt but I still don't like the feeling.



Everything is bonded properly I am sure of that.



I checked most of my circuits, the only ones showing the voltage reading across the neutral and ground are the ones with the fluorescent lights. All other light and outlet circuits read zero across the neutral and ground.



FYI the more fluorescent lights on a circuit, the higher the voltage reading.



I think that it has to be something with the ballasts.............

You are probably right. I'm assuming these are full size fluorescent fixtures with separate ballasts. If so its pretty easy to miswire the universal voltage ones as they generally have more than the typical three (hot neutral ground) leads. I would pull the cover on one of them and check it. Also an amp tong on the ground wire with the lights on would tell you a lot.


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[Alchymist]

If it's only happening on fluorescent lighting circuits, I'm going to take a WAG and say the lights have a filter circuit that shunts to the EGC. Probably some capacitor/inductor circuit to cut radiated noise. This will cause a small hot to EGC current flow, and when the EGC is disconnected from the bus, the voltage will become apparent.

 

[tlmartin84]

You are probably right. I'm assuming these are full size fluorescent fixtures with separate ballasts. If so its pretty easy to miswire the universal voltage ones as they generally have more than the typical three (hot neutral ground) leads. I would pull the cover on one of them and check it. Also an amp tong on the ground wire with the lights on would tell you a lot.


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They are a 2-wire ballast, one hot, one neutral/hot depending upon 120/240 application.

The only grounding is a screw on the frame.

Unfortunately my ammeter only reads to 10 amps! across the neutral and ground I am showing zero.

I AM ALSO SHOWING ZERO VOLTS ACROSS THE NEUTRAL AND GROUND AT MY PANEL.....

View media item 56185

 

[wyliesdiesels]

Umm thats a 4-wire fed panel but it looks like its using one of the neutral bars(left side) as the EGC.

Is the tie bar that connects the 2 bars together removed? Do u have continuity between the left and right bars?

 

[tlmartin84]

Tie bar is removed allowing it be used as a ground and has a ground screw through it bonding the panel.

 

[wyliesdiesels]

Ok good

 

[justsam]

Is the picture shown the main panel? Unless it is done ahead of this panel at the meter or other disconnect, neutral and EGC should be connected together.

 

[wyliesdiesels]

Is the picture shown the main panel? Unless it is done ahead of this panel at the meter or other disconnect, neutral and EGC should be connected together.

A main service panel would only be fed by 3-wire. This has a 4-wire feeder.

In #11, he said this is his subpanel.

 

[justsam]

A main service panel would only be fed by 3-wire. This has a 4-wire feeder.

In #11, he said this is his subpanel.

You are absolutely right!

Need to brush up on reading skills and visual acuity. Getting old is hell!

 

[wyliesdiesels]

You are absolutely right!

Need to brush up on reading skills and visual acuity. Getting old is hell!

Naw. Im young and I miss stuff sometimes. With so many threads going through this forum, its easy to mix 'em up!

 

[toplessHO]

looks to me like you ve got a loose neutral connection somewhere

 

[tlmartin84]

UPDATE:

Finally had some spare time, did a little more checking. Checked a few fixtures, across the ground and neutrals, it showed 2 V +/-.

Now here is the kicker, I unhooked the first one in the series from the lights "downtream" from it and wired it straight to the switch. (prior to wiring it, I checked all three wires coming in: 120V H-N 120V H-G 0V N-G) WHICH IS RIGHT).

Then after wired up I checked it and found that when I broke the ground and placed my meter between the housing and the ground wire I had 80V. I removed the ballast and let it hang and still 80V. This is what was shocking me originally..........not the +/-2 I had previously reported.

I thought ok, I have a problem somewhere but to make sure let me test a separate circuit. One Switch, One light........simple. Checked the bare wires with no fixture, 120, 120, 0 which was ok. Then I hooked the light up. THE SAME 80V SHOWED UP.

Apparently these lights are dropping 80V into the fixture housings at the "tombstones". I don't know how, I don't know why but they do...........

 

[wyliesdiesels]

A high impedance short in the ballast?

 

[tlmartin84]

I wouldn't think it is a short. They are brand new lights AND I removed the ballast from the housing.

It was hanging by the wires, bulbs removed. I pulled my wires out of the fixture to make sure they weren't shorting on it. At that point the ballast wires ran to the tombstones. It is a 4 light "long" fixture. Yellow wires go to the end tombstones and are jumpered. and the red and blue wires go to the tombstones in the middle.

AND still 80V.

It makes no sense.

 

[tlmartin84]

Also, wouldn't you think if it was a 80V short it would cause the lights to dim or something?

The lights still function fine with the ground broken....

 

[Alchymist]

I wouldn't think it is a short. They are brand new lights AND I removed the ballast from the housing.

It was hanging by the wires, bulbs removed. I pulled my wires out of the fixture to make sure they weren't shorting on it. At that point the ballast wires ran to the tombstones. It is a 4 light "long" fixture. Yellow wires go to the end tombstones and are jumpered. and the red and blue wires go to the tombstones in the middle.

AND still 80V.

It makes no sense.

Again:

If it's only happening on fluorescent lighting circuits, I'm going to take a WAG and say the lights have a filter circuit that shunts to the EGC. Probably some capacitor/inductor circuit to cut radiated noise. This will cause a small hot to EGC current flow, and when the EGC is disconnected from the bus, the voltage will become apparent.

 

[tlmartin84]

80V though, seems like a lot?

Also, they would have to be doing it at the tombstones since I dropped the ballasts. But I don't know how, there is no visible connection from the tombstone to the housing.

I believe you are correct, you would never notice it...........there are no indicators until you break the ground. So I wonder if most fluorescent lights are this way and no one notices it because the never break the ground...........