bonding riser RSC/PVC

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Mule

Senior Member
Location
Oklahoma
Probably a old topic, but Im installing a long tall riser that is partialy PVC with a RSC mast.....How do I properly bond the RSC? Never done this before.. Can I just fasten to the mast knob clamp bolt?
 

Mule

Senior Member
Location
Oklahoma
Probably a old topic, but Im installing a long tall riser that is partialy PVC with a RSC mast.....How do I properly bond the RSC? Never done this before.. Can I just fasten to the mast knob clamp bolt?

Ok...I guess this was a stupid question, since no one responded.....
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
In ths area, a pipe ground clamp is attached to the GRS conduut and bonded at the POCO service attachment. POCO does all the work.
 

Mule

Senior Member
Location
Oklahoma
In ths area, a pipe ground clamp is attached to the GRS conduut and bonded at the POCO service attachment. POCO does all the work.

Thanks got'r bonded this morning, just used a common sense approach.....now I hope the inspector has the same approach...haha
 

Mule

Senior Member
Location
Oklahoma
Sorry no pic's....The riser totaled nearly 30ft in circuit length which included 2 sticks of rigid and the rest was PVC that went hortizontal through studs. The RSC was installed up through a wall in a two story structure, then up through the roof deck, which will be fed over a parking lot. I had six heavy wall miny's clamped tightely above and below each of the three plates giving vertical support. I bolted the bare copper to two of these miny's that were in close proximity to one another. The service entrance conductors were only 100amp, so I thought the surface area of the two straps was suffiecent as they are heavy and wide. Then took the bare copper back to the bull's eye bonding point.....
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I just did one a week or so ago like that. What I did was add a lug to the long bolt that is part of the pipe weatherhead clamp, and used a nut to secure the lug.

I don't see that as code compliant. You're assuming that the bolt and the weatherhead is capable of carrying the potential fault current. I'm sure that the weatherhead was not tested for this or is not listed for that purpose.
 

Mule

Senior Member
Location
Oklahoma
I don't see that as code compliant. You're assuming that the bolt and the weatherhead is capable of carrying the potential fault current. I'm sure that the weatherhead was not tested for this or is not listed for that purpose.

Didnt say anything about the weatherhead? I asked at the beginging of this thread for proper connections and didnt get any response other that the clamp mentioned, and no ones stock such a animal around here......Oh well, I think it is sufficient. Im confident the inspector will pass it. Remember a riser is normally bonded via only through 4 very small hub screws. Hubs are pot metal and fastened to a painted meter can, and this method is used for much higher circuit values. I think the surface area of my method is sufficient to kick the 100 breaker upon a fault condition. However you are correct that it is not code compliant nor listed, but you will remember my thoughts on that from the past..:smile:
 
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macmikeman

Senior Member
I don't see that as code compliant. You're assuming that the bolt and the weatherhead is capable of carrying the potential fault current. I'm sure that the weatherhead was not tested for this or is not listed for that purpose.

Mule said it. If the whole riser was in rigid, and fault occurs at the weatherhead, my bet is that the listing agency has tested the fault carrying capabilities of that weatherhead in order to get it listed for service equipment. As for code comliant on the method, if I were to guess, the weatherhead securing bolts are probably where there is a problem with this method, simply because they secure the weatherhead, and we shouldn't be bolting grounding lugs to screws that secure things. However this is past the point on the screw where the securing is done and I just used the leftover tail, so as I see it it should be ok.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
I don't see that as code compliant. You're assuming that the bolt and the weatherhead is capable of carrying the potential fault current. I'm sure that the weatherhead was not tested for this or is not listed for that purpose.

I'd like to hear more opinions on this. I personally don't know if I have one yet... but suggesting that bolts should be listed for grounding and that the equipment you are bonding needs to be rated to carrying the fault seems counter-intuitive.

It's like, "bond equipment, unless that equipment can't handle the fault..."

Am I way off?
 

Cavie

Senior Member
Location
SW Florida
Around here, you would have to run a bond with the conductors out thru the weather head and connect to a ground clamp around the riser. The bond would have to come from the bonding of the service.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Around here, you would have to run a bond with the conductors out thru the weather head and connect to a ground clamp around the riser. The bond would have to come from the bonding of the service.
similiar here. The pipe ground clamp is required, but POCO will attach to the POCO neutral for you
 

electricmanscott

Senior Member
Location
Boston, MA
This is what I'd think to be code compliant. I think it was already mentioned. Bonding bushing on top end of riser pipe. Length of wire left long enough for the poco to connect to their neutral. I don't see how the other two methods mentioned by mule and macmike are legal.
 

Mule

Senior Member
Location
Oklahoma
My comments about the small screws where about a meter hub not the weatherhead. But either way, hub or weatherhead, they are both typicaly made of either cast aluminum or flimpsy pot metal. With this said, Im still confident my installation is safe, mechanicaly sound, and meets the intent of the code. but I'll agree not a listed part.

Im now curious if the mentioned bonding bushing will screw on, and the weather head clamp still function properly. If so, sounds like the solution to me.....If not, I've seen grounding clamps before, but in smaller sizes. They probably make a 2", but in my 35 years I've never seen one.

I would have prefered to run RSC all the way, and eliminate this hassle, but no way to get through 16" stud spacing with out complety notching.

Im not changing my method unless the inspector wants me too, but I've learned a couple of things here..............thanks
 

iwire

Moderator
Staff member
Location
Massachusetts
I just did one a week or so ago like that. What I did was add a lug to the long bolt that is part of the pipe weather head clamp, and used a nut to secure the lug.

I also see this as a problem, as odd as it seems that fitting would have to be listed for the purpose (250.8).

A simply grounding clamp onto the mast with a bonding jumper to the neutral at the weather head would be code compliant and how we would do it here if we wanted to keep the weather head. Usualy we do it per POCO specs for the steel riser at the pole, no weather head, just a bonding bushing at the top of the conduit packed with duct seal etc.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
I also see this as a problem, as odd as it seems that fitting would have to be listed for the purpose (250.8).

A simply grounding clamp onto the mast with a bonding jumper to the neutral at the weather head would be code compliant and how we would do it here if we wanted to keep the weather head. Usualy we do it per POCO specs for the steel riser at the pole, no weather head, just a bonding bushing at the top of the conduit packed with duct seal etc.

I don't see it yet... I'm sure the lug he installed is listed, and the bolt and nut seems to meet 250.8(A)(5).
 
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