#4 stranded grounding conductor
- Thread starter pecoman
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electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: #4 stranded grounding conductor
No. Conductors with type THHN insulation are not listed for direct burial.
No. Conductors with type THHN insulation are not listed for direct burial.
electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: #4 stranded grounding conductor
Oops. I stand corrected.
Oops. I stand corrected.
Re: #4 stranded grounding conductor
Look at the markings on your THHN wire. You will probably find that it is marked THHN/THWN which means it has a max. operating temp. of 90 degrees C in dry locations per 310.13 and 75 degrees C in wet locations and is suitable for use in wet locations.
Look at the markings on your THHN wire. You will probably find that it is marked THHN/THWN which means it has a max. operating temp. of 90 degrees C in dry locations per 310.13 and 75 degrees C in wet locations and is suitable for use in wet locations.
electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: #4 stranded grounding conductor
Most wire is dual rated THHN/THWN but being suitable for wet locations does not mean it can be directly buried. As Roger pointed out though, in this case what type insulation it has is immaterial since it is used for grounding/bonding.
Most wire is dual rated THHN/THWN but being suitable for wet locations does not mean it can be directly buried. As Roger pointed out though, in this case what type insulation it has is immaterial since it is used for grounding/bonding.
B
bthielen
Guest
Re: #4 stranded grounding conductor
Perhaps the insulation could be a factor. In a recent project I did at home I ran a four-wire supply to a building. I was instructed by the inpsector to rerun the grounding conductor because I used a bare conductor instead of an insulated conductor. In this case, the insulation would have to be rated for direct burial.
Bob
Perhaps the insulation could be a factor. In a recent project I did at home I ran a four-wire supply to a building. I was instructed by the inpsector to rerun the grounding conductor because I used a bare conductor instead of an insulated conductor. In this case, the insulation would have to be rated for direct burial.
Bob
- Location
- Illinois
- Occupation
- retired electrician
Re: #4 stranded grounding conductor
Bob,
What code section was cited to require an insulated grounding conductor? 250.118(1) permits a bare EGC. Was this a special occupancy of some type?
I see no reason for the insulation to be rated in this case because no insulation is required.
Don
Bob,
What code section was cited to require an insulated grounding conductor? 250.118(1) permits a bare EGC. Was this a special occupancy of some type?
I see no reason for the insulation to be rated in this case because no insulation is required.
Don
B
bthielen
Guest
Re: #4 stranded grounding conductor
I didn't question it at the time because it wasn't a big deal for me and my home project.
I was wiring a new pole building on my farm. I have a meter pole centrally located in my yard with a distribution panel (up to four 240v circuits) that supplies my house and other out-buildings. I added a 100A, 240v circuit breaker in the panel to supply the new building. I installed a 100A service entrance panel in the new building with GEC to a grounding electrode. I did not bond the "neutral" bus to the GEC in my new building therefore keeping my ground bus isolated from my "neutral" bus in my new building. I then ran 4-wire supply (2 hot, neutral, gnd) from the distribution panel to the new building (direct burial). I figured I'd be okay using a bare ground conductor from my distribution panel to the ground bus in the new building. I didn't fully understand his ruling but I was a little unsure with regard to my understanding of the code with regard to the building supply wiring anyway. He said something about parallel return to the source although I didn't quite get it because whether the ground conductor is insulated from earth or not, there is still a path to the distribution panel (source) via the ground conductor and/or earth or neutral in either case.
Perhaps someone can explain?
Bob
I didn't question it at the time because it wasn't a big deal for me and my home project.
I was wiring a new pole building on my farm. I have a meter pole centrally located in my yard with a distribution panel (up to four 240v circuits) that supplies my house and other out-buildings. I added a 100A, 240v circuit breaker in the panel to supply the new building. I installed a 100A service entrance panel in the new building with GEC to a grounding electrode. I did not bond the "neutral" bus to the GEC in my new building therefore keeping my ground bus isolated from my "neutral" bus in my new building. I then ran 4-wire supply (2 hot, neutral, gnd) from the distribution panel to the new building (direct burial). I figured I'd be okay using a bare ground conductor from my distribution panel to the ground bus in the new building. I didn't fully understand his ruling but I was a little unsure with regard to my understanding of the code with regard to the building supply wiring anyway. He said something about parallel return to the source although I didn't quite get it because whether the ground conductor is insulated from earth or not, there is still a path to the distribution panel (source) via the ground conductor and/or earth or neutral in either case.
Perhaps someone can explain?
Bob
Re: #4 stranded grounding conductor
I by no way meant to imply that any conductor that is listed for use in a wet location is also suitable for direct burial but we are talking about a grounding electrode conductor and I don't know of anyone who uses type UF or any other direct burial cable for their grounding electrode conductors.
I by no way meant to imply that any conductor that is listed for use in a wet location is also suitable for direct burial but we are talking about a grounding electrode conductor and I don't know of anyone who uses type UF or any other direct burial cable for their grounding electrode conductors.
Re: #4 stranded grounding conductor
The only difference I would see is that if it was a GEC it would be run by itself and if it was an EGC then it would probably be routed with the phase conductors in a cable assembly or in some type of conduit system that would be in the ground which is a wet location that would require appropiate conductors or an approved type of direct burial cable assembly.
The only difference I would see is that if it was a GEC it would be run by itself and if it was an EGC then it would probably be routed with the phase conductors in a cable assembly or in some type of conduit system that would be in the ground which is a wet location that would require appropiate conductors or an approved type of direct burial cable assembly.
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