EMT Connectors and Ground-Faults.

EMT Connectors and Ground-Faults.

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Compression going for the surface area.

Actually the best connection is a lose fitting connector/coupling and after the first major fault welding all fittings, lowering the resistance, assuming you did not use cast fittings.
 
brian john said:
Compression going for the surface area.
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Regarding surface area, consider a compression coupling, the conduit is cetered in the fitting with only that steel ring inside making contact, worse mabey, if there is a gasket inside. But the set screw jams the condiut to one side plus the screw making a tight fit.

Just a thought.
 
kornbln said:
Why would one not just pull a ground wire? Is it to save money?
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Don't ground me for my reply:grin: , but I always pull a grounding conductor. We went through this before, but I'd like to thank the forum for the poll. I always considered the conduit and couplings as a secondary means:wink:
 
I'm agree'n with 34 and 42.

It's a compression of the band, that's brought tight thus shrinking the band to wedge between the sleeve of the fitting , the conduit and the locking bolt ... the band is designed to be compressed.

Besides I'd rather get pinched from channel locks than stab myself!
 
her

her

Here your go ...
frizbeedog said:
You gotta learn how to do that multiple qoute thing man, 'cause now I gotta go back and read. :mad: ;) :grin:
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34
tmbrk said:
Assuming both are made up correctly I would think the compression type has more serface area and would provide a better ground path.

The worst has to be indenter type fittings. I've run into them where I've pulled the pipe right out of the fitting (inside a wall.:mad:)
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42
brian john said:
Compression going for the surface area.

Actually the best connection is a lose fitting connector/coupling and after the first major fault welding all fittings, lowering the resistance, assuming you did not use cast fittings.
Click to expand...
your desired readings
 
I have to say we make a mountain out of a mole hill here. :D

All the EMT fittings are listed for grounding. If your not comfortable with using fittings as the grounding path then pull a wire EGC. :smile:

All this talk about surface area etc, have any of you noticed what grounding methods actually pass UL testing?

Think of the ground whip on some light fixtures, or the Tek screwed foot lug in an HVAC unit. Or that I can use a 10 AWG as the grounding means for up to 60 amps. Or the fact that with a 'self grounding' receptacle the grounding path may be just the 6-32 screw and a very small spring steel clip wedges against it. Or the fact that 'Wagos' are suitable for grounding. Or that 'grounding clips' are acceptable.

My point is there are many ways to get it done, each one of us looks at it differently.

It is my opinion that if EMT was not providing good grounding results in the field the NEC would have changed the rules, each year people ask them to and it is rejected for lack of facts.

Here is the most recent panel statement to explain the rejection of 3 proposals asking for a 'wire' EGC.

Panel Statement: Studies show that all steel conduit is a reliable equipment grounding conductor in high temperature situations. UL white book does not require a wire type equipment grounding conductor. The technical substantiation does not support the proposal
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After reading Bob's post, and glancing through the other posts, I am of the belief that the members of this site should write their own code.


"The National I Believe it Should be Installed Like This" Electrical Code

NIBISIL Electrical Code


The code everyone designs, and everyone does what they think is good. It will revolutionize the industry. Just think, no more order, no need for inspectors, insurance costs through the roof, everybody does what they want, all customers satisfied. :cool: :grin:
 
Compression= two hands = fall off ladder
set screw= one hand = stay on ladder


National this is how I think it should be done Code.

Cast set screw fittings shall be used for landfill.

Exception: where recycling is readily available or occasionally considered.

Where recycling is available cast fittings shall be placed in a mostly empty drywall bucket along with steel handi boxes with 1-1'/2" knockouts , broken drill bits and extensions, 3-3/4" Lb covers, and mixtures of screws and dirt, until overflowing, and then placed in a dimly lit area of the shop to be tripped over, or carried around in the front end of a truck bed until everything dissolves.

Set screws shall be facing downward. ;)
 
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iwire said:
I have to say we make a mountain out of a mole hill here. :D

All the EMT fittings are listed for grounding. If your not comfortable with using fittings as the grounding path then pull a wire EGC. :smile:

All this talk about surface area etc, have any of you noticed what grounding methods actually pass UL testing?

Think of the ground whip on some light fixtures, or the Tek screwed foot lug in an HVAC unit. Or that I can use a 10 AWG as the grounding means for up to 60 amps. Or the fact that with a 'self grounding' receptacle the grounding path may be just the 6-32 screw and a very small spring steel clip wedges against it. Or the fact that 'Wagos' are suitable for grounding. Or that 'grounding clips' are acceptable.

My point is there are many ways to get it done, each one of us looks at it differently.

It is my opinion that if EMT was not providing good grounding results in the field the NEC would have changed the rules, each year people ask them to and it is rejected for lack of facts.

Here is the most recent panel statement to explain the rejection of 3 proposals asking for a 'wire' EGC.
Click to expand...

Grounding clips are as good as backstabbing. Sorry, just not for me. Am I alone here????
 
realolman said:
Compression= two hands = fall off ladder
set screw= one hand = stay on ladder


National this is how I think it should be done Code.

Cast set screw fittings shall be used for landfill.

Exception: where recycling is readily available or occasionally considered.

Where recycling is available cast fittings shall be placed in a mostly empty drywall bucket along with steel handi boxes with 1-1'/2" knockouts , broken drill bits and extensions, 3-3/4" Lb covers, and mixtures of screws and dirt, until overflowing, and then placed in a dimly lit area of the shop to be tripped over, or carried around in the front end of a truck bed until everything dissolves.

Set screws shall be facing downward. ;)
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I agree with that statement.
Also, I like the set screw connectors because the're easier to work with especially in a tight spot. The compression connectors can be a real pain in a tight spot since you have to use channel locks to tighted them. It's also hard to tighten the the compression connectors when the conduits are so closely run together at times.
 
76nemo said:
Grounding clips are as good as backstabbing. Sorry, just not for me. Am I alone here????
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Sorry, but I have no problem with properly-installed G-clips. Fault currents tend to expose the weak link in the grounding pathway, and I have never seen a G-clip failure.

Backstabbing, on the other hand . . . :rolleyes:
 
LarryFine said:
Sorry, but I have no problem with properly-installed G-clips. Fault currents tend to expose the weak link in the grounding pathway, and I have never seen a G-clip failure
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Same here, and that is for 35 + years. But for those who do see or have seen these failures, I do realize that certain atmospheric conditions, moon position, hung over installers, installers anticipating hangovers, weird contortionist positions, leap years, and a few other factors may come into play. ;)


Roger
 
No matter what you are using for an EGC, poor workmanship can render it ineffective. I worked on a retrofit of an old building and in the process, I found small holes burnt through the conduit at almost every coupling and the conduit was 3" rigid. The conduit was a mostly straight run and should have been easy to fully tighten, but it wasn't. When I got to a pull box, most of the back was missing. It appears that even the rigid did not quickly clear the fault.
 
don_resqcapt19 said:
. . . I found small holes burnt through the conduit at almost every coupling and the conduit was 3" rigid.
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There's no excuse for that. :rolleyes: On a kinda-sorta semi-related note:

I had a discussion with my (admittedly anally-retentive) EE friend about tightening GRC sections, specifically whether it matters whether one tightens a run piece by piece or all at once from one end of the run.

I maintain that, as long as pipe alignment and support friction are kept to the point that they don't impede the pipe turning, it shouldn't matter whether you tighten the pipe one joint at a time or all at once.

The torque applied at one end of multiple sections will transfer to whichever coupling is the loosest at any given moment, and when you're done, the total turns of the wrench handle will be the same either way.

In other words, if you have 10 joints to tighten, you can turn the wrench, say, 25 times at each coupling, or 250 times standing in one place. The torque applied to each and every coupling will be the same.

Opinions?
 
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