Wrong to use screw threads as a ground?

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jap

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You would hate me, I will grind the paint to bare metal when bonding an SDS, connecting a GEC to building steel.

You don't think that it is required by 250.12?


Maybe on the larger service disconnects, but, in general most service disconnect switches already have the neutral kit installed and you simply install the green bonding screw through the hole to the enclosure which I would hope satisfies the rule.

If not, there's probably thousands of service disconnects out there that are improperly bonded. I've never removed the factory installed neutral kit from a service disconnect, ground the paint off behind it, reinstalled the neutral kit, ground the paint off of the green bonding screw and installed it. I don't think all that's necessary.

I feel the threaded bonding screw you get cuts the paint out of the hole as it threads in and catches at least 2 threads.

I feel the same way about the studs in a Nema 12 Hoffman box, which are welded to the enclosure prior to being painted. If you install a ground lug over the stud of a Hoffman box and tighten a 3/8 shoulder nut down on the top of it, I feel the contact on the underside of the nut to the face of the lug is a good electrical conection.

I do however like you, grind the primer off of a beam when I drill a hole through it and add a lug.




JAP>
 
To what extent? I install the lug use my razor knife to outline the lug, then use my flathead to scrape it. So that the entire lug is surface to surface. Lets not forget that grounding could be the difference between someone getting a slight zing from a live wire or being hung up and seriously hurt or worse.

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Which reminds me of a service call i responded to after a maint guy got the *beep* knocked out of him when he completed the circuit of a gutter that had the grounding wire stolen, they pulled the neutral out to steal it but didnt finish. So when the tenants reported no power he was investigating, kneeled on the gound went to remove the cover and !BAM! Grounding may be a PIA sometimes bit it truely is the most important conductor of a circuit.

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jap

Senior Member
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To what extent? I install the lug use my razor knife to outline the lug, then use my flathead to scrape it. So that the entire lug is surface to surface. Lets not forget that grounding could be the difference between someone getting a slight zing from a live wire or being hung up and seriously hurt or worse.

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Awesome, yet grounding has nothing to do with keeping you from getting shocked.

JAP>
 

jap

Senior Member
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Electrician
To what extent? I install the lug use my razor knife to outline the lug, then use my flathead to scrape it. So that the entire lug is surface to surface. Lets not forget that grounding could be the difference between someone getting a slight zing from a live wire or being hung up and seriously hurt or worse.

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Probably ought to install the lug and rotate it 360 degrees then take it off and grind the paint off in a circle so when the wire gets installed in the lug and it turns a little bit it wont rotate back onto the paint that wasn't ground off.

JAP>
 

jap

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Electrician
Which reminds me of a service call i responded to after a maint guy got the *beep* knocked out of him when he completed the circuit of a gutter that had the grounding wire stolen, they pulled the neutral out to steal it but didnt finish. So when the tenants reported no power he was investigating, kneeled on the gound went to remove the cover and !BAM! Grounding may be a PIA sometimes bit it truely is the most important conductor of a circuit.

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No amount of "Grounding" would have kept him from getting the "Beep" knocked out of him.

JAP>
 
Epp wrong, had the gutter been grounded the voltage/ unbalanced load current coming off the neut would have had a path to ground and the gutter would not have been energized. Dont have to believe me, go open a neutral of a active circuit and grab a hold of the end comming from the load one time while grounded.

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jap

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Epp wrong, had the gutter been grounded the voltage/ unbalanced load current coming off the neut would have had a path to ground and the gutter would not have been energized. Dont have to believe me, go open a neutral of a active circuit and grab a hold of the end comming from the load one time while grounded.

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Your absolutely incorrect.

JAP>
 

jap

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Even though the thief stole the neutral conductor, evidently he didn't steal the grounding conductor.
The gutter was still energized even though it was connected to ground.
If what your saying is correct..... why did he get the "beep" knocked out of him?


JAP.
 

jap

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Electrician
So your saying that had the gutter had a ground wire from it to the ground he wouldn't have gotten shocked?


JAP>
 
Yes, because the grounded wire and the grounding wire are connected at the first means of disconnect. So if you take a continuity check between any grounding wire and grounded wire you will find there is continuity.

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jap

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Yes, because the grounded wire and the grounding wire are connected at the first means of disconnect. So if you take a continuity check between any grounding wire and grounded wire you will find there is continuity.

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You'll also find that if you leave all of the "Green Wires" in place and take the Neutral loose at the meter and complete the path between the return neutral current and the source,,,,
your still going to get your beeper knocked off.

The gutter and all of the conductive paths were energized when the neutral came loose from the meter "because" the neutral and ground were bonded together at the service disconnect , as they are required to be, and the return current was simply trying to find a path back to its source.

This is not a ground fault scenario that would have tripped the main, it's simply the result of a loose neutral.

JAP>
 

jap

Senior Member
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Electrician
Bonding would prevent that shock, grounding might not.

Bonding would not have prevented the shock in the scenario he's describing.
Bonding is what caused the gutter and all the other parts to become energized.

The maintenance man became parallel with the neutral return path.

Nothing would have prevented this shock short of removing the neutral return current prior to him touching the energized parts.

JAP>
 
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