This a little long and involved, but if it were easy...
Background: We use a lot Okonite CLX. It is an MC-HL, continuous sheath MC, listed under UL1569. In a three conductor cable, the grounding conductor is split into three sections, set into the interstices. The three added together meet the requirements of 250.122. This construction clearly meets the UL requirements.
We have been using this cable for quite a few years. The practice was to take the three grounding conductors, chuck the ends into a cordless drill, and twist the three tightly together, and terminate under one mechanical, setscrew type lug. The method produces a nice nearly round, stranded, single conductor - looks good, works well.
Recently the AHJ decided we were incorrectly terminating the grounding conductors. As near as I can tell, the issue is the lugs are listed (labeled - marked?) for only one conductor and the cable has the grounding conductor split into three sections. He insisted we use a three hole lug and pick up each section separately. Okay, we can - most times; not always easy - say coming into a disconnect there isn't a lot of room. And if there is space, one could always pick up the three, along with a suitable sized single conductor, under a split bolt and terminate the single conductor - messy looking cludge, but possible.
The thought had never occurred to me this could be an issue. We hire good journeymen, they do good work; my inclination is to stay out of their way, especially on craft issues.
However, when this came up, I reviewed the CLX product data sheet, the Okonite cable handbook, UL 1569, and the NEC. The Okonite literature does not give any specific instructions on terminating the three. My interpretation of UL 1569 is they intended the three sections to be treated as one grounding conductor - since each section by itself is too small to meet 250.122. I couldn't find anything in the NEC that really addresses it.
I think our practice is good workmanship and meets the intent of the code, but if the AHJ says we are not meeting the letter of the NEC, then we aren't - he is the one with the hammer. However, he and I generally have cordial, polite conversation, and he responds to gentle discussions with code books in hand. I think we have an unspoken agreement, "I don't p--s him off, and he doesn't get stuck."
The Questions:
1. For those of you using an MC cable with sectioned grounding conductors, how are you terminating them?
2. I am not seeing the safety or reliability is improved by terminating the three separately. Am I missing anything here?
3. Can anybody lead me to references that show methods of terminating the three? Maybe I missed something in the NEC -- or there are common practices shown in journeyman handbooks, or even other cable mfgs literature.
We aren't stopped here, nor in trouble, but I would still like to know if I am goofed up, or get some clues as to reasonable arguments that what we have been doing is okay. Any help on this will be graciously appreciated.
carl
Background: We use a lot Okonite CLX. It is an MC-HL, continuous sheath MC, listed under UL1569. In a three conductor cable, the grounding conductor is split into three sections, set into the interstices. The three added together meet the requirements of 250.122. This construction clearly meets the UL requirements.
We have been using this cable for quite a few years. The practice was to take the three grounding conductors, chuck the ends into a cordless drill, and twist the three tightly together, and terminate under one mechanical, setscrew type lug. The method produces a nice nearly round, stranded, single conductor - looks good, works well.
Recently the AHJ decided we were incorrectly terminating the grounding conductors. As near as I can tell, the issue is the lugs are listed (labeled - marked?) for only one conductor and the cable has the grounding conductor split into three sections. He insisted we use a three hole lug and pick up each section separately. Okay, we can - most times; not always easy - say coming into a disconnect there isn't a lot of room. And if there is space, one could always pick up the three, along with a suitable sized single conductor, under a split bolt and terminate the single conductor - messy looking cludge, but possible.
The thought had never occurred to me this could be an issue. We hire good journeymen, they do good work; my inclination is to stay out of their way, especially on craft issues.
However, when this came up, I reviewed the CLX product data sheet, the Okonite cable handbook, UL 1569, and the NEC. The Okonite literature does not give any specific instructions on terminating the three. My interpretation of UL 1569 is they intended the three sections to be treated as one grounding conductor - since each section by itself is too small to meet 250.122. I couldn't find anything in the NEC that really addresses it.
I think our practice is good workmanship and meets the intent of the code, but if the AHJ says we are not meeting the letter of the NEC, then we aren't - he is the one with the hammer. However, he and I generally have cordial, polite conversation, and he responds to gentle discussions with code books in hand. I think we have an unspoken agreement, "I don't p--s him off, and he doesn't get stuck."
The Questions:
1. For those of you using an MC cable with sectioned grounding conductors, how are you terminating them?
2. I am not seeing the safety or reliability is improved by terminating the three separately. Am I missing anything here?
3. Can anybody lead me to references that show methods of terminating the three? Maybe I missed something in the NEC -- or there are common practices shown in journeyman handbooks, or even other cable mfgs literature.
We aren't stopped here, nor in trouble, but I would still like to know if I am goofed up, or get some clues as to reasonable arguments that what we have been doing is okay. Any help on this will be graciously appreciated.
carl