Jpflex
Electrician big leagues
- Location
- Victorville
- Occupation
- Electrician commercial and residential
Just to clarify, it is still not clear to me if ALL concentric or eccentric knockouts have to be removed or if some larger knockouts can remain while securing conduit and to meet specific code.
One of my grounding and bonding books brought me a lot of confusion when it said all concentric and eccentric knockouts must be removed. What would be the purpose of having multiple sized concentric or eccentric knockouts if this were true and larger knockouts could not remain and be used?
Does removing all knockouts allow listed connectors with matching size conduit to be installed without bonding bushings at the line side of service or systems over 250 volts to ground?
Assuming we remove all eccentric and concentric knockouts at the line side of service, it seems we would NOT have to install bonding bushings if we use listed fittings for the conduit such as EMT connectors with standard locknuts? 250.92 (B) (2) threadless couplings and connectors if made wrench tight for metal raceways and metal clad cables. Would an inspector likely fail a listed EMT connector and locknut to a service or system with over 250 volts to ground just because most often bonding bushings are installed whether or not it has to be there?
Clearly a rigid metal conduit with just two locknuts could not be used to meet code for this application. However, from what I’m reading, bonding bushings do not have to be installed at the line side of service or systems over 250 volts AS LONG AS “ELECTRICAL CONTINUITY AT SERVICE EQUIPMENT….ARE ENSURED BY ONE OR MORE OF TGE FOLLOWING”
(3) THREAD-LESS COUPLINGS AND CONNECTORS IF MADE WRENCH TIGHT FOR METAL RACEWAYS AND METAL CLAD CABLES
My interpretation to this is a listed threaded or thread-less EMT connector without a bonding bushing. However, you don’t seem to ever see many examples of this as an acceptable method without bonding bushings being shown.
Is my bonding and grounding book wrong or misleading? Can concentric or eccentric knockouts remain to support smaller conduit?
It makes more sense that oversized knockouts can remain and bonding bushings not be used in various cabinets and breaker panels as long as listed conductive fittings are terminated at the end of conduit such as EMT?
One of my grounding and bonding books brought me a lot of confusion when it said all concentric and eccentric knockouts must be removed. What would be the purpose of having multiple sized concentric or eccentric knockouts if this were true and larger knockouts could not remain and be used?
Does removing all knockouts allow listed connectors with matching size conduit to be installed without bonding bushings at the line side of service or systems over 250 volts to ground?
Assuming we remove all eccentric and concentric knockouts at the line side of service, it seems we would NOT have to install bonding bushings if we use listed fittings for the conduit such as EMT connectors with standard locknuts? 250.92 (B) (2) threadless couplings and connectors if made wrench tight for metal raceways and metal clad cables. Would an inspector likely fail a listed EMT connector and locknut to a service or system with over 250 volts to ground just because most often bonding bushings are installed whether or not it has to be there?
Clearly a rigid metal conduit with just two locknuts could not be used to meet code for this application. However, from what I’m reading, bonding bushings do not have to be installed at the line side of service or systems over 250 volts AS LONG AS “ELECTRICAL CONTINUITY AT SERVICE EQUIPMENT….ARE ENSURED BY ONE OR MORE OF TGE FOLLOWING”
(3) THREAD-LESS COUPLINGS AND CONNECTORS IF MADE WRENCH TIGHT FOR METAL RACEWAYS AND METAL CLAD CABLES
My interpretation to this is a listed threaded or thread-less EMT connector without a bonding bushing. However, you don’t seem to ever see many examples of this as an acceptable method without bonding bushings being shown.
Is my bonding and grounding book wrong or misleading? Can concentric or eccentric knockouts remain to support smaller conduit?
It makes more sense that oversized knockouts can remain and bonding bushings not be used in various cabinets and breaker panels as long as listed conductive fittings are terminated at the end of conduit such as EMT?
