In the nec 250.92b it states where theres knockouts you need to put a bonding jumper (ssbj) to clear any possible fault. If you have nonmetallic conduit the bonding jumper is not required. What if you have a metallic conduit with no eccentric knockouts is the bonding jumper required
Service bonding
- Thread starter pedro1200
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Does the metallic raceway contain service conductors?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
So if there are concentric or eccentric KOs you'll need a bonding bushing only on one end of the raceway. For a fully punched KO a bonding locknut would also be code compliant in lieu of a bonding bushing.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The service raceway requires a method of bonding that is beyond that of a standard locknut. So depending on the type of KO that method can vary. A bonding bushing would cover every type of KO.
Yes but by only mentioning the ko implies in my opinion that this is the only time. I think that they failed to say that its required regardless if theres ko or not thats what confused me. Thanks
Were talking line side of service disconnect here;
In my 2017 version that section you quoted 250.92(B) says in part:
"Standard locknuts or bushings shall not be the only means for the bonding required by this section but
shall be permitted to be installed to make a mechanical connection of the raceway(s)."
So regardless of how you make the KO, punch it out, concentric whatever it is, you can't use the standard two locknuts one inside one out or old school metal bushing with locknut outside.
Options are 250.92(B) 1-4,
If you use a hub that qualifies under item (2), bonding locknuts or bushings under (4).
In my 2017 version that section you quoted 250.92(B) says in part:
"Standard locknuts or bushings shall not be the only means for the bonding required by this section but
shall be permitted to be installed to make a mechanical connection of the raceway(s)."
So regardless of how you make the KO, punch it out, concentric whatever it is, you can't use the standard two locknuts one inside one out or old school metal bushing with locknut outside.
Options are 250.92(B) 1-4,
If you use a hub that qualifies under item (2), bonding locknuts or bushings under (4).
Yes, but they confuse it with this as the preface in that paragraph:
"Bonding jumpers meeting the requirements of this article shall be used around impaired connections, such as reducing washers or oversized,
concentric, or eccentric knockouts. Standard locknuts or bushings shall not be the only means for the bonding required by this section but
shall be permitted to be installed to make a mechanical connection of the raceway(s)."
To me, this part should come later and I'm confused as to what it means. Historically, all service raceways have more stringent bonding requirements requiring threaded hubs, threadless couplings, bonding locknuts/bushings, etc. They should say this first. If there happens to be an eccentric knockout or reducing washer, I'm unclear as to whether these methods just listed are sufficient or if you need a bonding jumper directly to the raceway too.
"Bonding jumpers meeting the requirements of this article shall be used around impaired connections, such as reducing washers or oversized,
concentric, or eccentric knockouts. Standard locknuts or bushings shall not be the only means for the bonding required by this section but
shall be permitted to be installed to make a mechanical connection of the raceway(s)."
To me, this part should come later and I'm confused as to what it means. Historically, all service raceways have more stringent bonding requirements requiring threaded hubs, threadless couplings, bonding locknuts/bushings, etc. They should say this first. If there happens to be an eccentric knockout or reducing washer, I'm unclear as to whether these methods just listed are sufficient or if you need a bonding jumper directly to the raceway too.