EGC: Conduit vs. Wire

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No doubt that many here have reviewed this info but it may be worth posting. The IAEI green book on grounding establishes some parameters on the lenght of different size raceways with a max ocpd that are deemed suitable as an egc without using a conductor. But that chart is not a NEC requirment. Just some thoughts.


http://www.steelconduit.org/pdf/groundingpart1.PDF
 
Our 50 yr. old industrial facility consisting of multiple buildings and elaborate testing structures, recently conducted a survey of the condition of equipment ground fault paths. Original construction relied entirely on conduit as the EGC. At some later time a dedicated ground conductor became required with each circuit. Our survey found numerous conduits rusted completely in two, or the box they were terminated to, rusted away. These were generally in areas not likely to ever be noticed by anyone. The ground path did not exist. A dedicated ground wire, properly installed by a conscientious electrician, has a better chance of surviving over time.
 
e57 said:
Effectively grounded to mounting means is not an effective fault path per se - but does help - in most cases - hurt if isolated and energized. :D Someday ask me about the dishwashers who went on strike due to multiple faults at various equipment and WALLS..... Boy ....was that a fun job!
Click to expand...



Well shoot, don't stop there,.........
 
76nemo said:
Well shoot, don't stop there,.........
Click to expand...
Got a call late to a burrito shop - the manager had the dishwashers refusing to work - thay said they kept getting shocked... When I get there the manager is all hissy fit, and tells me to just go put them at ease, making like it is all in thier heads... So I go back there, and me and the dishwasher have a short conversation in what little spainish I know...

"De aqu? a all?, y aqu? a all?." - (Yes - I just used a translator engine for that...) And I knew what he meant - 'From here to there, and here to there.'

He was pointing at the dishwasher, and the adjecent sink, and the dishwasher and a sheetmetal wall.

So I pull out my meter - yep 120, and 120 - 208! Each item had a different phase...

So I ask how long it was like that, and the guy says - "ANOS!"

Then I go back and I tell the dismissive manager about it, and we'll have to do it T&M to find it - and that I'll need to shut stuff off quite possibly here and there... And I had already shut off the dishwasher but the sink and wall were still live... He wants nothing to do with this or what I told him and asks me to leave...

I call my boss and tell him - who is now appauled. And since I was there - he know felt liabilty coming his way. He says - go pull their meter - stick it in your van, and call the cops... Which I do... The cops called an on-call inspector who has me put the meter back, but writes a red tag for the shop for health and safety.

The next day I'm back there again with my boss and another manager... District Manager for the chain I guess... And I get to work finding out what they all were. The sheet metal was live from a 3" screw - one of the many it was installed with - it had been live the entire time the store had been there... The dish washer had the liq-tite that fed it rot off at the fitting - no ground and stinger leg shorted to it... (Which kind of ties in with this thread...) The sink was the same as the other wall - but a different circuit.
 
e57 said:
Got a call late to a burrito shop - the manager had the dishwashers refusing to work - thay said they kept getting shocked... When I get there the manager is all hissy fit, and tells me to just go put them at ease, making like it is all in thier heads... So I go back there, and me and the dishwasher have a short conversation in what little spainish I know...

"De aqu? a all?, y aqu? a all?." - (Yes - I just used a translator engine for that...) And I knew what he meant - 'From here to there, and here to there.'

He was pointing at the dishwasher, and the adjecent sink, and the dishwasher and a sheetmetal wall.

So I pull out my meter - yep 120, and 120 - 208! Each item had a different phase...

So I ask how long it was like that, and the guy says - "ANOS!"

Then I go back and I tell the dismissive manager about it, and we'll have to do it T&M to find it - and that I'll need to shut stuff off quite possibly here and there... And I had already shut off the dishwasher but the sink and wall were still live... He wants nothing to do with this or what I told him and asks me to leave...

I call my boss and tell him - who is now appauled. And since I was there - he know felt liabilty coming his way. He says - go pull their meter - stick it in your van, and call the cops... Which I do... The cops called an on-call inspector who has me put the meter back, but writes a red tag for the shop for health and safety.

The next day I'm back there again with my boss and another manager... District Manager for the chain I guess... And I get to work finding out what they all were. The sheet metal was live from a 3" screw - one of the many it was installed with - it had been live the entire time the store had been there... The dish washer had the liq-tite that fed it rot off at the fitting - no ground and stinger leg shorted to it... (Which kind of ties in with this thread...) The sink was the same as the other wall - but a different circuit.
Click to expand...

Good thing you went there and not me. That manager would not have walked out of there on his own 2 feet.
 
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