250.148
- Thread starter Mkline01
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Maybe all it would take would be for the Different Sections to be a little closer for clarity.
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kwired
Electron manager
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jaggedben
Senior Member
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In my opinion the code generally prohibits using a metal LB in the middle of a non-metallic raceway run such as PVC. Maybe there would be a weird case where 250.86 Exception 1 would apply. 250.86 Exception 3 covers buried metal elbows but LBs are supposed to be accessible so they don't get to benefit from that. I can't really think of an approved way to bond a metal LB other than by using a bonded raceway on at least one side of it.
I agree that the rule on splicing in boxes doesn't make a lot of sense on the face of it. If the general idea is that bonding through metal raceways is not reliable enough, then the rule would make more sense if it required wire EGCs everywhere, or for raceway runs exceeding a certain length, or something like that. Not that I think such a rule would improve the code.
:slaphead:
I suspect we got here through a general notion that some redundancy is a good thing, and this is a relatively simple way for the code to build in some redundancy, without making a really complicated rule that might in the end be no less arbitrary.
I agree that the rule on splicing in boxes doesn't make a lot of sense on the face of it. If the general idea is that bonding through metal raceways is not reliable enough, then the rule would make more sense if it required wire EGCs everywhere, or for raceway runs exceeding a certain length, or something like that. Not that I think such a rule would improve the code.
:slaphead:
I suspect we got here through a general notion that some redundancy is a good thing, and this is a relatively simple way for the code to build in some redundancy, without making a really complicated rule that might in the end be no less arbitrary.
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jaggedben
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For anybody that feels like doing the research, the wording of this section changed to it's present wording in 2002, before that, if more than one EGC entered a box they all had to be joined together and connected to the box regardless of whether or not there were other splices.
Roger
Roger
Carultch
Senior Member
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Here is an illustration that will help and you are right, if there are no splices in the box the EGC can be the metallic conduit as ActionDave says.
Roger
Interesting rule. The graphic really should show two separate examples, to be clear on this, but we have what we have. I see the intent of this being to prepare for a splice to fail.
Suppose one of the metal raceways terminates with a bonding bushing and a standard locknut (no KOs remaining), which would establish continuity to the enclosure. Is it acceptable to land the EGC on the bonding bushing's lug, and still meet the intent of this rule?
If you read the general statement carefully, it requires "any equipment grounding conductor(s) associated with those circuit conductors shall be connected within the box or to the box". The circuit conduits are equipment grounding conductors? It is only subsection (C) that requires connection to a metal box. You have three choices for compliance with (C). I believe your example would comply as long as other equipment grounding conductors are also connected to that of your example. Note the box itself is not specifically called an equipment grounding conductor anywhere in the NEC.
kwired
Electron manager
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But is part of the EGC path when there is no wire EGC pulled in the raceways.
Which seems to be forgotten about once one decides to pull in his own wire type EGC......Hence the dilema.
JAP>
Part of the equipment grounding path, but not part of the equipment grounding conductor... technically.
Question: If a wire-type EGC is pulled, is an EGC-qualifying metal conduit still an EGC?
kwired
Electron manager
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- NE Nebraska
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- EC
Part of the equipment grounding path, but not part of the equipment grounding conductor... technically.
Question: If a wire-type EGC is pulled, is an EGC-qualifying metal conduit still an EGC?
First sentence is the answer to the question in the second sentence here.
In a very, very... very indirect manner, I suppose. :happyno::happyyes:
Part of the equipment grounding path, but not part of the equipment grounding conductor... technically.
Question: If a wire-type EGC is pulled, is an EGC-qualifying metal conduit still an EGC?
The answer to the question is Yes.
Regardless of whether a wire type EGC is pulled or whether that wire type EGC it's spliced or not.
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