Egc by raceway conduit connection and with grounding conductor

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electricalist

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Location
dallas tx
We implement a egc some choose the raceway and other qualifying material. Some run an actual grounding conductor . If the first method is compliant who do some choose also to run grounding conductor as well. Is the a system that requires both. Any pros and cons are aporeciated. Yes ive seen plenty of conduits seperated
 

Ponchik

Senior Member
Location
CA
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Electronologist
We implement a egc some choose the raceway and other qualifying material. Some run an actual grounding conductor . If the first method is compliant who do some choose also to run grounding conductor as well. Is the a system that requires both. Any pros and cons are aporeciated. Yes ive seen plenty of conduits seperated

Just for that reason I always install the conductor in EMT, FMC and other conduits. I don't do any work with RMC but if I did I will still install the conductor.
 

electricalist

Senior Member
Location
dallas tx
True story we were changing out hi bays with t5 f bays. Abour 100 my supervisor says check that out there pipes seperated. Conduit was egc there. I say can I waste some company time he says sure. . Conduits were still grounded ob both sides im thinking crap. 277 v lights. How. Well it seems the conduit is all strapped with metal to framework boxes self tapped ti bldg steel . It was grounded from every direction
 

augie47

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Tennessee
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In answer to your OP, one are that requires both is Art 517.
 

iwire

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Massachusetts
It is worth pointing out that the conduit will have less impedance than the EGC you might pull in it.

And as far as article 517 they consider the pipe to be the primary EGC with the wire EGC to be the back up to it.
 

electricalist

Senior Member
Location
dallas tx
I know opinions can go wrong but where would you feel better pulling a ground wire. Even it wasnt required. I have some co workers who always do and some that dont. The boss said if they feel better with it then do it. It cant hurt .
 

ActionDave

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Durango, CO, 10 h 20 min from the winged horses.
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I know opinions can go wrong but where would you feel better pulling a ground wire. Even it wasnt required. I have some co workers who always do and some that dont. The boss said if they feel better with it then do it. It cant hurt .
I rarely pull a green in metal conduit. It is just a feel good thing IMO. One of the reasons I don't have any fear of a loose connection is like you said in an earlier post; I've got a metal pipe in a metal structure with other metal pipes interconnected, a fault is gonna clear even if one tried to stop it.

Two other things, in my community anyway, the green to everything guys are some sloppy pipe runners and since I started doing more service work I have seen a lot of bad splices on greens.
 

electricalist

Senior Member
Location
dallas tx
3 1" pipes 6 120 v ccc in each all coming from the same panel into 1 12x12 go another 150 to another 12x12 then to jbox sub destination. Leadman says pull greens in every pipe bonding bushings comibg in plastic going out land all grounds to ground bar kit and make sure u sand and tap the holes for ground bar. I say you know why jboxes only have one tapped hole instead of a bunch like a panel. He says no . I say ofcoarse yes sir ill get it done
 

iwire

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Location
Massachusetts
3 1" pipes 6 120 v ccc in each all coming from the same panel into 1 12x12 go another 150 to another 12x12 then to jbox sub destination. Leadman says pull greens in every pipe bonding bushings comibg in plastic going out land all grounds to ground bar kit and make sure u sand and tap the holes for ground bar. I say you know why jboxes only have one tapped hole instead of a bunch like a panel. He says no . I say ofcoarse yes sir ill get it done

Don't confuse code requirements with job specifications. Often the specifications included with the contract have requirements that go well beyond the NEC.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
Actual case... Especially when metal conduit is used in stick/pole framed buildings movement and settling can cause conduits to separate and when used in buildings exposed to the elements oxidation/corrosion of the surface where mating in couplings becomes resistive and can create excessive heat during a fault.
Had a building on a fairgrounds where there was a fault on a circuit utilizing the EMT as EGC. Got there in time to witness the coupling get hot enough to burn the wood structure and it also emanated sparks which were landing in the straw! Now we've got a fire.
So it's always a good idea to install a wire EGC.
 

electricalist

Senior Member
Location
dallas tx
Don't confuse code requirements with job specifications. Often the specifications included with the contract have requirements that go well beyond the NEC.
The drawings are my first stop when I get to a job right after I find a place as close to the work as possible to park.. I'm a little overweight.
 
It is worth pointing out that the conduit will have less impedance than the EGC you might pull in it.

And as far as article 517 they consider the pipe to be the primary EGC with the wire EGC to be the back up to it.
The conduit will have less impedance than an actual conductor? I would have guessed the other way around. How is that possible with all the connections in the raceway?
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
Which we have to also assume with a wire EGC.
But as mjc pointed out, in any long run there are likely to be more raceway connections then wire EGC connections.
For small area work in pipe the two numbers are more likely to be close. But even then you will have at least two connections, maybe four counting fitting to pipe and fitting to box with EMT, and only one wire connection added per run.
 
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