Ok so I know how we all agree that we don't have to worry about bonding sealtite or flex, when it's not considered an egc. But what about when you encounter an eccentric or concentric KO. Or reducing washers. I know how we like to compare it to bonding PVC. But this is still different. Because if you think about it, if a ground fault did occur within the raceway in question, it still has a metallic core that will become part of the ground fault current path. Electricity doesn't care what the Nec allows. So I think in accordance with 250.4(A)(3) Bonding of electrical equipment. That you would be required to properly bond the raceway in question, under the circumstances stated above. Any thoughts or opinions?
bonding sealtite?
- Thread starter ggonza
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flashlight
Senior Member
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- NY, NY
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- Electrician, semi-retired
Are you sure this is true ? That any size KO in a concentric is listed to carry fault current ?
SG-1
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IMO if one is using the listed connectors for sealtite or flex, then it is bonded about as good as it can be. The concentric knockout would not be the weak link in this situation. The sealtite/flex would probably unravel first. It has to be bonded because it is likely to become energized.
The NEC has reasons for all the restrictions on this type of wiring method.
Concentric knockouts become a weak link when the system voltage is 277V to ground, because the fault current is much higher at this voltage level. This is why junction boxes are listed for 277V.
The NEC has reasons for all the restrictions on this type of wiring method.
Concentric knockouts become a weak link when the system voltage is 277V to ground, because the fault current is much higher at this voltage level. This is why junction boxes are listed for 277V.
SG-1
Senior Member
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- Ware Shoals, South Carolina
Intended to say. This is why some junction boxes are rated or listed for 277V.
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I personally would not count on reducing washers as a fault path however the NEC and UL allow it.
I've been researching this until my head hurts. You might find the attached post interesting, especially post #62 in regard to sealtite:
http://forums.mikeholt.com/showthread.php?t=113235&highlight=reducing+washers&page=7
I was glad to see Bob testify on reducing washers. I thought they were accepted even though, as he states, I personally would not rely on them.
http://forums.mikeholt.com/showthread.php?t=113235&highlight=reducing+washers&page=7
I was glad to see Bob testify on reducing washers. I thought they were accepted even though, as he states, I personally would not rely on them.
SG-1
Senior Member
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- Ware Shoals, South Carolina
Look at 250.92(B)(4).
LarryFine
Master Electrician Electric Contractor Richmond VA
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Then there's the rest of us.
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