wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Change:
250.92(B) Method of Bonding at the Service.
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).
Electrical continuity at service equipment, service raceways, and service conductor enclosures shall be ensured by one or more of the following methods:
(1) Bonding equipment to the grounded service conductor by an applicable method in 250.8(A)
(2) Connections made up wrenchtight using threaded couplings, threaded entries, or listed threaded hubs on enclosures
(3) Threadless connections on couplings and connectors if made up tight for metal raceways and metal-clad cables
(4) Other listed devices, such as bonding-type locknuts, bushings, or bushings with bonding jumpers
Substantiation:
The current wording of 250.92(B)(3) admits some ambiguity with respect to threadless connectors. The wording may be taken to mean that a threadless connector plus its included locknut is sufficient both for electrical continuity of the raceway or cable to the connector and for electrical continuity of the connector to the enclosure. This interpretation is not precluded by the parent text stating "Standard locknuts or bushings shall not be the only means for the bonding . . ." since the connection to the enclosure does not consist of "only locknuts" but consists of a connector plus its locknut.
However, my understanding is that the intention is that the allowance of 250.92(B)(3) is intended to only apply to the threadless side of the connector, and not the threaded side. Changing the subject of 250.92(B)(3) to "threadless connections" makes this clear. The threaded side of the connector still needs to comply with one of the other portions of 250.92(B), such as 250.92(B)(2) if threaded into a hub, or 250.92(B)(4) if the connector is used with a bonding wedge, bonding locknut, or bonding bushing.
250.92(B) Method of Bonding at the Service.
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).
Electrical continuity at service equipment, service raceways, and service conductor enclosures shall be ensured by one or more of the following methods:
(1) Bonding equipment to the grounded service conductor by an applicable method in 250.8(A)
(2) Connections made up wrenchtight using threaded couplings, threaded entries, or listed threaded hubs on enclosures
(3) Threadless connections on couplings and connectors if made up tight for metal raceways and metal-clad cables
(4) Other listed devices, such as bonding-type locknuts, bushings, or bushings with bonding jumpers
Substantiation:
The current wording of 250.92(B)(3) admits some ambiguity with respect to threadless connectors. The wording may be taken to mean that a threadless connector plus its included locknut is sufficient both for electrical continuity of the raceway or cable to the connector and for electrical continuity of the connector to the enclosure. This interpretation is not precluded by the parent text stating "Standard locknuts or bushings shall not be the only means for the bonding . . ." since the connection to the enclosure does not consist of "only locknuts" but consists of a connector plus its locknut.
However, my understanding is that the intention is that the allowance of 250.92(B)(3) is intended to only apply to the threadless side of the connector, and not the threaded side. Changing the subject of 250.92(B)(3) to "threadless connections" makes this clear. The threaded side of the connector still needs to comply with one of the other portions of 250.92(B), such as 250.92(B)(2) if threaded into a hub, or 250.92(B)(4) if the connector is used with a bonding wedge, bonding locknut, or bonding bushing.