A feeder for a panel is being run for a critical care area in a hospital. EMT is being used with plastic bushings at each termination and junction point.
Article 517.19(D) requires that grounding be ensured on a metal raceway by: (1) A grounding bushing and a copper jumper or (2) connection to threaded hubs or bosses or (3) bonding type locknuts or bushings.
One argument is that a standard EMT set screw connector is in fact a threaded boss(the collar on the fitting being the boss). Therefore the connector is sufficient and no other additional bonding is necessary.
The other interpretation is that the code is asking for something in addition to ENSURE that the raceway is bonded to the enclosure, and that a boss is a conduit body. Therefore a bonding bushing with a copper bonding jumper would be required for the EMT connector.
Article 517.19(D) requires that grounding be ensured on a metal raceway by: (1) A grounding bushing and a copper jumper or (2) connection to threaded hubs or bosses or (3) bonding type locknuts or bushings.
One argument is that a standard EMT set screw connector is in fact a threaded boss(the collar on the fitting being the boss). Therefore the connector is sufficient and no other additional bonding is necessary.
The other interpretation is that the code is asking for something in addition to ENSURE that the raceway is bonded to the enclosure, and that a boss is a conduit body. Therefore a bonding bushing with a copper bonding jumper would be required for the EMT connector.