Locating A Service Call "Shock"

[360Youth]

Our GC refered us to a customer of his that said she received a shock while trying to replace a broken lens on an outside luminaire. I have been twice and found no shock, exposed/bare conductors, or loose ground. My initial thought was maybe neutral current was jumping to grounding wire somehow but I have found no evidence. We have pulled off for now because of the old adage "you can't fix what isn't broke" and GC is not yet ready to authorize hours of troubleshooting for a currently (pun not intended )non-existent problem. Any ideas on what I may be missing?

 

[sawdust454]

I am sure you checked, but is the ungrounded conductor on the center of the socket and the grounded conductor connected to the shell "polarity check?

 

[charlie b]

It's a stretch, but here is my only guess. Do you know the difference in how it feels to get a very brief 120 volt shock ("brief" meaning just long enough to let you pull your hand away), and how it feels when a sharp object (like a broken lens) contacts your hand and pushes against a nerve without breaking through the skin? You do? Well, you are a professional, and we all have gotten a shock at least once.

I will often suggest a healthy dose of skepticism, when you listen to anyone (particularly a non-professional) trying to describe symptoms of an electrical problem. Don't take anything they say as absolute truth, until you ask a few probing questions, and until you have done some investigations of your own. Given the results of your investigations so far, this might not have actually been an electric shock.

 

[360Youth]

I am sure you checked, but is the ungrounded conductor on the center of the socket and the grounded conductor connected to the shell "polarity check?

I did not check voltage at the screw shell or continuity checks because everything appeared at the connections to be correct. There could be an internal crossover tho, so that is a good point.

 

[360Youth]

It's a stretch, but here is my only guess. Do you know the difference in how it feels to get a very brief 120 volt shock ("brief" meaning just long enough to let you pull your hand away), and how it feels when a sharp object (like a broken lens) contacts your hand and pushes against a nerve without breaking through the skin? You do? Well, you are a professional, and we all have gotten a shock at least once.

I will often suggest a healthy dose of skepticism, when you listen to anyone (particularly a non-professional) trying to describe symptoms of an electrical problem. Don't take anything they say as absolute truth, until you ask a few probing questions, and until you have done some investigations of your own. Given the results of your investigations so far, this might not have actually been an electric shock.

I questioned the GC on that. Did the HO catch a piece of flaking metal and only believe that she got a shock? He stated that in her email she felt it with both hands. I am guessing as she was attempting to remove the cover.

 

[LarryFine]

Any ideas on what I may be missing?

Two:

1. Use a non-contact tester to check for a hot housing. It uses the earth as a reference (through your body.)

2. Plug an extension cord into a known-properly-wired receptacle (not on same circuit.) Use a solenoid tester between cord slots and fixture wires and parts.

 

[growler]

We have pulled off for now because of the old adage "you can't fix what isn't broke" and GC is not yet ready to authorize hours of troubleshooting for a currently (pun not intended )non-existent problem.

I can, I would simply replace the existing fixture with a new one and call it a safety precaution. Check you power and ground and call it a day and send them a bill for something tangable.

 

[qcroanoke]

I'm with Charlie and Growler.
Probably nothing there. You checked everything and all was good.
I've gotten the non existent shock Charlie spoke of too.
Change the light to make her feel better about it. Check everything again and move on.

 

[360Youth]

I can, I would simply replace the existing fixture with a new one and call it a safety precaution. Check you power and ground and call it a day and send them a bill for something tangable.

Trying to find a replacement if for nothing more than the lens. The problem is a matching the exising lights with a new one.

 

[satcom]

Did the GFCI for the fixture trip?

 

[hurk27]

I have had a nerve in my elbow if I move it a certain way it will feel just like I was shocked, actually one time i had actually thought I got shocked until I realized all the power was off:roll:

But if this is an older home with K&T, be aware of those Chicago three ways, as they switch the shell from hot to neutral, search the forum about these if so, as there are some posted diagrams of how they work and why there not allowed anymore.

The shell can be hot even with the light off with a Chicago 3-way.

 

[LarryFine]

I have had a nerve in my elbow if I move it a certain way it will feel just like I was shocked, actually one time i had actually thought I got shocked until I realized all the power was off:roll:

That reminds me of the time I saw a friend react to his new vibrating text-pager.

I called it "the emperor's new bee." He couldn't escape it. So funny!

 

[Power Tech]

I have one of those nerves in my wrist. It seems to only pop when I am working on power.

OP: Was the lady barefoot?

Is there any landscape fixtures or underground wiring.

Like Larry said, a non contact tester works great for this.

 

[roger3829]

Did the GFCI for the fixture trip?

What GFCI ?

 

[satcom]

What GFCI ?

Exactly, there may be a bootleg neutral, somewhere in the house wiring, we usually check to see if they had any recess lighting added, of other added lighting with switches, the handy dandy and 2 wire electricians, will use the ground to pick up a return, when no neutral is present in the box, they are extending from, they have no idea how dangerous it is , they just know the light lights. Even the outdoor fixture may be feed with a bootleg neutral.

 

[vinster888]

OP: Was the lady barefoot?

my first thought

 

[LarryFine]

OP: Was the lady barefoot?

my first thought

There still should have been no shock.

 

[PetrosA]

There still should have been no shock.

There could be if there's a break in an underground line and the concrete/stone slab she was standing on was energized. I had a call like this in a small bathroom a few years back. The drain was still metal, the hot and cold had been replaced with plastic. It turned out there was a break in a UF cable under the sidewalk outside the bathroom wall that was energizing the drain pipe through contact with the basement foundation wall. The current was traveling through the drain, up the water stream (when turned on) and through the water to the city water supply. It was a slight, but uncomfortable buzz that you'd feel while washing your hands.

 

[RH1]

i will often suggest a healthy dose of skepticism, when you listen to anyone (particularly a non-professional) trying to describe symptoms of an electrical problem. Don't take anything they say as absolute truth, until you ask a few probing questions, and until you have done some investigations of your own. Given the results of your investigations so far, this might not have actually been an electric shock.

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