Egc

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electricalist

electricalist

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dallas tx
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Am i understanding this correctly.
I can maintain my egc by establishing a bond to any point on the ges.
Example, a conduit , pvc leave a panel and ends at a 4 sq. J box screwed to structural steel.
Does the connection from the box to the bldg steel qualify as a compliant ground?
 
electricalist said:
Am i understanding this correctly.
I can maintain my egc by establishing a bond to any point on the ges.
Example, a conduit , pvc leave a panel and ends at a 4 sq. J box screwed to structural steel.
Does the connection from the box to the bldg steel qualify as a compliant ground?
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No and no.

EGC installation rules are found somewhere above 250.114 or so.
 
So its ok to drill and tap a lug to bldg steel for protection against lightning but a drilled and tapped screw securing a metal box to bldg steel could not be a egc
 
electricalist said:
So its ok to drill and tap a lug to bldg steel for protection against lightning but a drilled and tapped screw securing a metal box to bldg steel could not be a egc
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I don't know about the lighting part.

As far as I know you can not use the building steel as an EGC. So, another words, you can not have your circuits run in Non Metallic conduit with metallic enclosure and use the building steel as an EGC.
 
I probably understand that it would not be compliant although imho it could be no better or worse than the jbox where a R/Y nut was used when a B/G nut for the grounds would be right .
Maybe i just feel like a structure thats built for a grounding means and strapping and securing from a grounding perspective would be safer than all the cause they didnt care grounding methods i see.
 
electricalist said:
So its ok to drill and tap a lug to bldg steel for protection against lightning but a drilled and tapped screw securing a metal box to bldg steel could not be a egc
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Correct. A Grounding Electrode System does not a proper Equipment Ground make.

electricalist said:
I probably understand that it would not be compliant although imho it could be no better or worse than the jbox where a R/Y nut was used when a B/G nut for the grounds would be right .
Maybe i just feel like a structure thats built for a grounding means and strapping and securing from a grounding perspective would be safer than all the cause they didnt care grounding methods i see.
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Guys who build buildings are not in charge of making sure the steel they use is good at clearing electrical faults. Hopefully the guys that install the electrical do make sure everything they install is good at clearing a fault.
 
Mr. Dave i agree that its our job to make it safe. I think that if there was 1 column in a bldg that was designed to be identified as a structual ground it could be like how the resi slab crews will bend a rebar into the wall as a cee for us.
 
electricalist said:
Mr. Dave i agree that its our job to make it safe. I think that if there was 1 column in a bldg that was designed to be identified as a structual ground it could be like how the resi slab crews will bend a rebar into the wall as a cee for us.
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It's not just resi for rebar and still part of the grounding electrode system.
 
One of the issues with a "remote" equipment grounding conductor is 300.3(B).

The electrical issue is the increase in the impedance of the fault return path where the EGC is run remote for the ungrounded conductors. While on lower current circuits it doesn't make any real difference, but where you have circuits above 400 amps or so, the increase of the impedance caused by a remote fault return path, can limit the fault current to the point where the OCPD takes much longer to clear the fault. Remember, on a solidly grounded system, the hazard exists until the fault is cleared.
 
rlundsrud said:
I would think you would have the potential for inadvertently creating ground loops as well.
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That is what got me on the subject.
Lets say you have a panel secured to unistrut that is secured to bldg steel then ran emt to a disconnect for a hot water heater. Flexed to the heater with a ground in all raceways.
You could take every ground loose and it would still be grounded in more ways than i felt like counting.
So when we talk about safety by the bond of ground to grounding conductor i want to know what path the fault took.
 
The fault currents take all paths in inverse proportion to their impedance. If you can identify one path that will clear the fault, the rest just improve the situation.
In general multiple ground/EGC paths are not a problem since none of those paths carry normal current.
 
electricalist said:
That is what got me on the subject.
Lets say you have a panel secured to unistrut that is secured to bldg steel then ran emt to a disconnect for a hot water heater. Flexed to the heater with a ground in all raceways.
You could take every ground loose and it would still be grounded in more ways than i felt like counting......
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Yep, its true. Yet the green to everything spec continues to gain steam.
 
rlundsrud said:
I would think you would have the potential for inadvertently creating ground loops as well.
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Ground loops or multiple paths for the fault return are not an issue. They cause no harm.

Multiple connections of the grounded conductor to the grounding system do cause problems.
 
electrofelon said:
Why does everyone want to heat water that is already hot? :lol: sorry I couldnt resist. Ive made it one of my life's goals to eliminate that phrase from the lexicon.
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"A heater to produce Domestic Hot Water"
As distinct from a heater to feed water to a space heating system.
Just saying "water heater" is not redundant, but is also slightly ambiguous.
 
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