When do you have to pull a EGC when you run conduit?

[zappy]

Like say a motor, you run conduit to it, do you have to pull a EGC too?

 

[raider1]

Depends on whether or not the wiring method itself counts as an equipment grounding conductor.

Take a look at 250.118 for the list of equipment grounding conductors.

Chris

 

[brian john]

And of course specifications and any local codes.

 

[brett711]

is that hard to pull a ground wire... just pull it, there is no garantee that locknuts and fittings will always stay tight.

 

[brian john]

is that hard to pull a ground wire... just pull it, there is no guarantee that lock nuts and fittings will always stay tight.

And Brett Who is paying for this? YOU?

Lets say Parallel Runs of 4-500 kcmil copper 350 feet.

Also there is no guarantee that the copper connections are going to be made properly, if the same slacker that did a poor job on the lock nuts lands the EGC, well the whole job goes to heck.

I normally do not like to cross post, I recently put this on another forum.


Something to consider when debating running an copper EGC or not.

On commercial projects with multiple conduits, copper water lines, metal studs, metal ducts, I-beams, re-bar or concrete in contact with the earth, this is all part of the grounding path. I doubt the resistance of a copper EGC can be any lower that all these paths combined. Though I have read that fault current, while taking many of the paths noted tends to stay close to the faulted conductors.

Just a thought.


Oh and after the first fault copper EGC or not many times the EMT connectors and couplings if steel will weld to the EMT.

 

[nakulak]

are you piping all the way to the motor ? (if you are using greenfield for the last bit due to flexibility, then you must pull an egc) 348.60 2005

 

[brian john]

are you piping all the way to the motor ? (if you are using greenfield for the last bit due to flexibility, then you must pull an egc) 348.60 2005

He said like say a motor? Radier1 covered that in his response I THINK?

 

[tryinghard]

NEC requires one or more of the types listed in 250.118 and the equipment ground needs to be run with the phase conductors (travel with them) to function correctly.

Sometimes job specifications dictate but situations, criticality, and intuition should always dictate.

Any type used from the list in 250.118 must be correctly installed or it would be in violation.

The purpose of the equipment ground fault path is to allow an extremely low resistance path to source and by doing so a short will cause extremely high amperes and open the circuit, instantaneously at best.

 

[benaround]

Oh and after the first fault copper EGC or not many times the EMT connectors and couplings if steel will weld to the EMT.

It has been said that even though a copper conductor is run in an EMT pipe, that the

major portion of the fault current still flows on (in) the pipe, not the wire.

 

[Pierre C Belarge]

I find this type of discussion interesting.

Why is there such a distrust of EMT and/or Rigid as the "effective ground fault current path"?

If this judgement is due to improper methods or poor work quality, then Brian has already stated why that will not matter.


The NEC is written based on all installations will be properly installed. If the installation(s) are properly installed, then any of the methods permitted in 250.118 are acceptable.



As an inspector who has seen many, many installations of all types of methods, I can say that human error is the number 1 reason for grounding type failures, not mechanical reasons. So, it would not matter if it was EMT or an actual conductor. Poor workmanship is poor whether or not one method has been choosen over the other.

 

[masterinbama]

I don't remember if it was here or the other forum. Some one posted a study that showed the fault clearing capacity of 300' of 1/2 EMT VS. 300' of #12 THHN copper. The EMT carried more than twice the amps before failure than the wire.
Any one remember this?

 

[dcspector]

I don't remember if it was here or the other forum. Some one posted a study that showed the fault clearing capacity of 300' of 1/2 EMT VS. 300' of #12 THHN copper. The EMT carried more than twice the amps before failure than the wire.
Any one remember this?

Yes I do and agree. However, read Pierre's Post #10. Makes all the difference in the world.

 

[don_resqcapt19]

Does the wording in 348.60 (2005) act to require an internal EGC when flex is installed where flexibility is required, or can you use an external bonding jumper?

 

[dcspector]

Does the wording in 348.60 (2005) act to require an internal EGC when flex is installed where flexibility is required, or can you use an external bonding jumper?

Don, who are you addressing this to? Just asking.

 

[petersonra]

A couple places come to mind.

Medical areas that require redundant grounding.

Classified areas.