GEC & Bonding?

Smart $

Esteemed Member
Location
Ohio
fair enough...it's a 2" nipple so it seems really silly to me and not to mention I have to be able to explain this to employees. I really don't like doing something because someone simply said to...that can make things really confusing. I am grateful for the patience and feedback!
Bonding only one end isn't always an option. We think this way because we often install grounded services. When installing an ungrounded service, you have no choice* but to bond both ends, because there is no grounded conductor to bond the enclosure.

*Running a bonding jumper would work, but it pretty much defeats what you are trying to get away with in the first place.
 

mwm1752

Senior Member
Location
Aspen, Colo
Key to the bonding in this section is "prior to disconnect" & you being asked only to bond the GRC -- your enclosurers are bonded with a conductor -- Use PVC & no issues about raceway bonding
 

kwired

Electron manager
Location
NE Nebraska
They want more then just a standard locknut to provide the bonding to metal service raceways.

Bonding locknuts, bonding bushings, bolt on hubs, integral to the enclosure hubs - are all acceptable means.

IMO it doesn't need to be both ends, if it did we would regularly see bond connections on supply end of service masts.
 

jahilliard

Senior Member
You're right we are not quite on the same page...my translation is that a means other than a locknut is required for impared connections. If not an impaired connection then two locknuts is sufficient. That's always been my understanding and how we have done installations. For example if we use a knockout set to create an opening in a solid cabinet we do not need a bonding bushing. If we have concentric KO's at the entry we are required to use a bonding bushng per 250.92(B). Thats been my understanding from way back. "Bonding Jumpers meeting the requirements of this article shall be used around impaired connections". That translates, IMO, to addressing impaired connections and the jumpers required for impaired connections. If not impared, the two locknuts required to mechanically secure the Rigid nipple are sufficient. is this not the case? And it's difficult to see how that specific section can be translated any other way than being specific to impaired connections.
 

mwm1752

Senior Member
Location
Aspen, Colo
Read the 2 sentences in 250.92(B) individually not as a run in sentence -- now go to 250.97 to relate to wiring other than services
 

kwired

Electron manager
Location
NE Nebraska
You're right we are not quite on the same page...my translation is that a means other than a locknut is required for impared connections. If not an impaired connection then two locknuts is sufficient. That's always been my understanding and how we have done installations. For example if we use a knockout set to create an opening in a solid cabinet we do not need a bonding bushing. If we have concentric KO's at the entry we are required to use a bonding bushng per 250.92(B). Thats been my understanding from way back. "Bonding Jumpers meeting the requirements of this article shall be used around impaired connections". That translates, IMO, to addressing impaired connections and the jumpers required for impaired connections. If not impared, the two locknuts required to mechanically secure the Rigid nipple are sufficient. is this not the case? And it's difficult to see how that specific section can be translated any other way than being specific to impaired connections.
I used to think about the same way on this matter. You are overlooking the part that says "Standard locknuts or bushings shall not be the only means for the bonding required by this section". Impaired or not impaired connection you can not use standard locknuts or bushings to do the bonding of a service raceway. I don't know whether the wording has changed over the years but that is what it now says and has said for at least a couple code cycles.
 

iwire

Moderator
Staff member
Location
Massachusetts
You're right we are not quite on the same page...my translation is that a means other than a locknut is required for impared connections. If not an impaired connection then two locknuts is sufficient.
But that is not the case regardless of you having been doing it that way.

Unimpaired connection requires a 'special' lockout' minimum

Impaired connection requires a wire jumper minimum.
 

kwired

Electron manager
Location
NE Nebraska
But that is not the case regardless of you having been doing it that way.

Unimpaired connection requires a 'special' lockout' minimum

Impaired connection requires a wire jumper minimum.
Lockout?:)


wrong word aside, that is about as simple an explanation as it can be ....I think.
 

Smart $

Esteemed Member
Location
Ohio
... is this not the case? And it's difficult to see how that specific section can be translated any other way than being specific to impaired connections.
It is not... as has already been confirmed by the others.

As mentioned by mwm1752, do not read the paragraph as one run-on sentence. There are similar instances throughout the Code. Learn to read these as each sentence is a related (as in the purpose of a paragraph) but completely separate requirement.
 

jahilliard

Senior Member
Ok, I'm still struggling to understand it that way but it makes sense I guess. After thinking about it for a little bit it'll probably be clear. thanks
I admit seprating the sentences does help...and good lord PVC is the answer!:D
ALSO...the 250.97 reference brings it all home for me! Thank you!
 
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kwired

Electron manager
Location
NE Nebraska
Ok, I'm still struggling to understand it that way but it makes sense I guess. After thinking about it for a little bit it'll probably be clear. thanks
I admit seprating the sentences does help...and good lord PVC is the answer!:D
I've seen many many cases where improper bonding was done with a service raceway and never developed any catastrophic issues, but I can only assume they want to cover the worst case scenario.

Have removed many 1970's installs that have a RMC nipple between meter socket and service panel on back side of wall that don't even have locknuts on outside of cabinets, as well as a lot of EMT risers out of the ground to service equipment into concentric/eccentric KO's and nothing but standard locknut on the fitting.
 
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