Expansion Fitting

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Smart $ said:
You two keep resorting to the bonding being established through the wire EGC. 250.96(A) CLEARLY says with or without supplementary EGC, which includes the wire EGC. Without the wire EGC, the metal conduit run would serve as the EGC. That's what it means. You must install a run of metal conduit as if it is the only EGC. And where flexible conduits are not permitted to serve as an EGC, you have the same condition.
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I am sure all of us have seen EMT couplings have come loose at which point there is NO effective ground fault current path. So, seeing that do we have to install the wire type EGC in a conduit? NO, so I don't think a mechanical continuity (for bonding purposes) is required unless it the sole EGC for the circuit.

You must install a run of metal conduit as if it is the only EGC. with the same token can we say. "every conduit must have a EGC wire type as if the couplings and connectors will be loose"

Just the way that I see it.
 
Smart $ said:
... Without the wire EGC, the metal conduit run would serve as the EGC. That's what it means. You must install a run of metal conduit as if it is the only EGC. ...
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The conduits on each side of the expansion fitting are suitable and function as an EGC, even without a bonding jumper around the expansion joint.
 
Smart $ said:
You must install a run of metal conduit as if it is the only EGC.
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Then why do you agree the underground PVC run that has RMC emerging from grade at the ends doesn't need additional bonding jumpers? It really is no different.

Is it because it is a PVC run with sections of RMC in it vs. a RMC run with section of PVC in it? I don't think it really matters.

If there is 200 feet of PVC and 10 feet of RMC at each end or if there is 8 feet of PVC and 10 feet of RMC at each end, either way you still have metal raceway - non metallic raceway - metal raceway in the run.
 
kwired said:
Then why do you agree the underground PVC run that has RMC emerging from grade at the ends doesn't need additional bonding jumpers? It really is no different.

Is it because it is a PVC run with sections of RMC in it vs. a RMC run with section of PVC in it? I don't think it really matters.

If there is 200 feet of PVC and 10 feet of RMC at each end or if there is 8 feet of PVC and 10 feet of RMC at each end, either way you still have metal raceway - non metallic raceway - metal raceway in the run.
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As I said in the beginning, it is not spelled out explicitly in the Code. As you have pointed out, it is clearly not a black and white determination. The gist of this conversation is regarding a lengthy run of metal conduit with LFMC for only a short section, serving to mitigate expansion-deflection damage. Discounting the use of a wire EGC per 250.96(A), the metal conduit would serve as an EGC... but the LFMC is not permitted to serve as an EGC.
 
don_resqcapt19 said:
I thought we were talking about an installation where there was an EGC of the wire type inside the raceway.
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We are. But 250.96(A) says a metal raceway that serves as an EGC, with or without supplementary EGC (such as a wire EGC), must be electrically continuous (i.e. an effective ground fault current pathway). I'm saying that means a wire type EGC run in the conduit must be disregarded, and a bonding jumper is required around a short section of LFMC in the run, that doesn't qualify as an EGC.
 
Smart:
your concerns is having an effective ground fault current path for the circuit or your concern is bonding of the conduit that is separated by the non metallic expansion fitting?
 
edward said:
Smart:
your concerns is having an effective ground fault current path for the circuit or your concern is bonding of the conduit that is separated by the non metallic expansion fitting?
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My concern is proper interpretation and implementation of 250.96(A) for the scenario in the OP.
 
Art 100 definitions:
Bonded (Bonding). Connected to establish electrical continuity and conductivity.

Bonding Conductor or Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.


Bonding Jumper, Equipment. The connection between two or more portions of the equipment grounding conductor.
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I don't see how the EGC pulled through the raceway fails to accomplish what is in each of these definitions if it connects to both the metal raceways. Continuity between the raceways may involve more than one bonding jumper, but eventually they attain electrical continuity.
 
kwired said:
Art 100 definitions:


I don't see how the EGC pulled through the raceway fails to accomplish what is in each of these definitions if it connects to both the metal raceways. Continuity between the raceways may involve more than one bonding jumper, but eventually they attain electrical continuity.
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That's the problem... 250.96(A) says "with or without" supplementary EGC. No problem with the "with" aspect. It is the "without" aspect you are not seeing. In American English grammar, a conditional clause set off by commas using "with or without..." is equivalent to "disregard..."
 
Smart $ said:
We are. But 250.96(A) says a metal raceway that serves as an EGC, with or without supplementary EGC (such as a wire EGC), must be electrically continuous (i.e. an effective ground fault current pathway). I'm saying that means a wire type EGC run in the conduit must be disregarded, and a bonding jumper is required around a short section of LFMC in the run, that doesn't qualify as an EGC.
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Based on that you would never be able to use a section of non-metallic raceway between two sections of metallic raceway unless you installed an external bonding jumper around the non-metallic raceway.
In my opinion the conduits of both sides of the expansion joint are suitable as EGCs as long as an EGC of the wire type has been installed in the raceway. I understand your objection based on the code wording, but like I said, that would prohibit the use on non-metallic raceway sections between metallic raceway sections and I don't see that as the intent of the code rule.
 
What if you have two expansion joints between the wire EGC termination points?

Is the middle section of raceway protected?
 
don_resqcapt19 said:
Based on that you would never be able to use a section of non-metallic raceway between two sections of metallic raceway unless you installed an external bonding jumper around the non-metallic raceway.
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Well 250.96(A) is in the section on bonding ;)


In my opinion the conduits of both sides of the expansion joint are suitable as EGCs as long as an EGC of the wire type has been installed in the raceway. I understand your objection based on the code wording, but like I said, that would prohibit the use on non-metallic raceway sections between metallic raceway sections and I don't see that as the intent of the code rule.
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How often do we actually install non-metallic sections in a run of metal raceway? Isn't it more often than not that we install metallic sections of raceway in runs of non-metallic raceway? Isn't bonding of the metallic sections of the latter type addressed in other bonding requirements?

Additionally, the objection isn't even concerning metallic vs. non-metallic. LFMC is considered a metallic raceway.
 
iwire said:
What if you have two expansion joints between the wire EGC termination points?

Is the middle section of raceway protected?
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In that case the expansion fitting would have to be listed for grounding or you would have to install a jumper around it. In the case of a single expansion fitting the load end raceway is bonded by the EGC that has been run inside the raceway.
 
Smart $ said:
Well 250.96(A) is in the section on bonding ;) ....
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So you are telling us that when we use a non-metallic underground raceway with metallic raceways at each end that we have to install an external bonding jumper around the underground non-metallic raceway.
 
Smart $ said:
How often do we actually install non-metallic sections in a run of metal raceway? Isn't it more often than not that we install metallic sections of raceway in runs of non-metallic raceway?
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You said the same thing two different ways??

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor,
cable sheath, enclosures, frames, fittings, and other metal
non–current-carrying parts that are to serve as equipment
grounding conductors, with or without the use of supplementary
equipment grounding conductors, shall be bonded
where necessary to ensure electrical continuity and the capacity
to conduct safely any fault current likely to be imposed
on them.
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I think if the code wanted you to bond around all expansion joints, etc no questions asked, they would of omitted "that are to serve as equipments grounding conductors." Otherwise I would buy your argument Smart.
 
Smart $ said:
That's the problem... 250.96(A) says "with or without" supplementary EGC. No problem with the "with" aspect. It is the "without" aspect you are not seeing. In American English grammar, a conditional clause set off by commas using "with or without..." is equivalent to "disregard..."
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250.96(A):

(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.
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I see you reading "to ensure electrical continuity", as meaning " to ensure it is electrically continuous" They have similar meaning but not the same.
 
Cow said:
You said the same thing two different ways??
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I know. It was intentional, to emphasize a nuance that you guys just aren't seeing in this matter. Perhaps you guys will eventually. :(


Cow said:
I think if the code wanted you to bond around all expansion joints, etc no questions asked, they would of omitted "that are to serve as equipments grounding conductors." Otherwise I would buy your argument Smart.
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Yes, it could be worded much, much better. But we are stuck with it the way it is. Anyone care to look up its origination (proposal and such)?
 
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