Bonding bushing on flex connectors

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electricalist

electricalist

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Location
dallas tx
I see flex connectors with bonding bushings on them in almost every xfmr I've seen.
I learned its not necessary.
My buddy does bond his flex connectors on one end. Because he wants too and got tagged for not bonding both ends of the secondary of the xfmr.. Is there something I'm missing?
I IMG_20150601_120757.jpg
 
IMO, who ever gigged it is missing something.
The restriction on grounding with flex in 250.118 means that in most transformer situations the flex not a ground so bonding bushings or equivalent to bonding PVC :)
 
augie47 said:
IMO, who ever gigged it is missing something.
The restriction on grounding with flex in 250.118 means that in most transformer situations the flex not a ground so bonding bushings or equivalent to bonding PVC :)
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I didn't think it is it possible to electrically bond to PVC.
Are you saying that a bonding bushing on the flex conduit would serve no more purpose than a bonding bushing on a PVC male adapter?

What about FMC and LFMC? The M of course stands for metal, which would mean it would need to be bonded.
Are some LFMC types better at carrying a bond than other types? Like the kind with the embedded ground wire in the metal coils?
 
Carultch said:
......What about FMC and LFMC? The M of course stands for metal, which would mean it would need to be bonded.
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If you have a piece of FMC over six feet or used on a circuit greater than twenty amps you pull a green in it, so a bond bushing does nothing to make anything better or safer. It doesn't matter if it is for lights in a ceiling or a 75kva transformer.

Are some LFMC types better at carrying a bond than other types? Like the kind with the embedded ground wire in the metal coils?
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Liquidtite can be used as an equipment ground up to sixty amps for sizes 3/4 up to 1 1/4. The wire acts as a shorting conductor across the coils so the metal functions as an equipment ground when ground fault current hits it.
 
Since the FMC is being used to provide flexibility a wire type EGC is required, also FMC is not permitted to serve as a SSBJ. The use of a bonding bushing on a flexible raceway which does not qualify as an EGC or as a SSBJ seems silly and as Augie stated akin to putting them on PVC.
 
It gets even better.
He made my buddy phase every conductor except the grounds,,,,,purple, then phase on top of purple , the trade colors. The neutrals are black- phased purple and grey. All the branch circuits are purple thhn then, brown A orange B and yellow C..
I think there's a power struggle amist.
 
electricalist said:
It gets even better.
He made my buddy phase every conductor except the grounds,,,,,purple, then phase on top of purple , the trade colors. The neutrals are black- phased purple and grey. All the branch circuits are purple thhn then, brown A orange B and yellow C..
I think there's a power struggle amist.
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Where in the NEC, is there any requirement to use purple wire or tape anywhere?

I thought the industry norm is:
Black/Red/White for 120/240 single phase
Black/Red/Blue/White for 120/208 three phase
Black/Orange/Blue/White for 120/240 high leg delta
Brown/Orange/Yellow/Gray for 277/480 three phase

Also that phase color requirements are no longer code requirements, except the high leg. And I can see the reason for this. There might be a desire to deviate from the industry norm to match an existing building that has a different scheme. Also, when you have an exotic voltage like 380 delta, you might want to use your own custom scheme, if you have to distinguish it from 277/480 in the same facility.
 
I think that the purple is just to call attention to the phase tape (as, for example, you are phasing a black wire black.) :)
If you only used purple wire for ungrounded conductors you would not need the purple tape.

The code just requires identification and does not really care how you do it (except for reserved colors like white, gray, and green.)
 
The same inspector wants all branch circuits to begin and end in their respective phase color.
I really have no problem with his over doing it but try putting in the bid a price for phasing every thing purple then another phase on top but its not a NEC requirement.
 
electricalist said:
The same inspector wants all branch circuits to begin and end in their respective phase color.
I really have no problem with his over doing it but try putting in the bid a price for phasing every thing purple then another phase on top but its not a NEC requirement.
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I would fight this guy to the ends of the earth. We would not get along. I cannot stand those inspectors that pull the AHJ card without code or at least some common sense to back it up.
 
luckylerado said:
I would fight this guy to the ends of the earth. We would not get along. I cannot stand those inspectors that pull the AHJ card without code or at least some common sense to back it up.
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I suspect he would tell you that he is just asking for "common sense" requirements. That is a problem because it is subjective. I would rather he stick to enforcing the code
 
mkgrady said:
I suspect he would tell you that he is just asking for "common sense" requirements. That is a problem because it is subjective. I would rather he stick to enforcing the code
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I agree, he is just eating up our time with non sense.
Ahj can be tricky, I have had the ones that I have said what's the code reference and they played fair after that. Those I have asked to call their boss and they were OK.
Those those who want some crazy stuff done and the minute you ask what they point out every single thing they can find.
 
mkgrady said:
I suspect he would tell you that he is just asking for "common sense" requirements. That is a problem because it is subjective. I would rather he stick to enforcing the code
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I thought the rule is that any citation by an inspector, has to be based on a specific code requirement.

The only place where an inspector's own interpretation would be allowed, would be in cases where the code is subject to interpretation. For instance, on the issue of physical damage. There are situations I can give, ask everyone I know who knows the NEC, half of them would say it is subject to physical damage, while half of them would say it isn't.
 
infinity said:
Since the FMC is being used to provide flexibility a wire type EGC is required, also FMC is not permitted to serve as a SSBJ. The use of a bonding bushing on a flexible raceway which does not qualify as an EGC or as a SSBJ seems silly and as Augie stated akin to putting them on PVC.
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The fact a raceway is not in itself an EGC does not mean the raceway itself does not require bonding.

Consider that FMC is an allowed service raceway. 230.43(15)

Do we have to bond it?
 
iwire said:
The fact a raceway is not in itself an EGC does not mean the raceway itself does not require bonding.

Consider that FMC is an allowed service raceway. 230.43(15)


Do we have to bond it?
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It's metal so of course yes, but the FMC is bonded by the use of a listed FMC connector a separate bonding bushing is not required.
 
I was thinking the same thing , it's bonded about as good as it's gonna be at the connector.
If the ahj said he wanted a bare ground twisted around the outside of the flex I'd say that makes more sense.

Sent from my LGLS620 using Tapatalk
 
infinity said:
It's metal so of course yes, but the FMC is bonded by the use of a listed FMC connector a separate bonding bushing is not required.
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IMO being a service raceway special bondong means are required.

Another one to think on.

You run a 480\277 volt 200 amp feeder with a copper EGC in EMT. You use 4' of FMC at the and and the FMC enters a concentric KO of a disconnect.

Bonding bushing required right?
 
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