When a metal service raceway terminates to an enclosure without a ringed knockout one end of the raceway must be bonded by a bonding jumper or a bonding-type locknut. Standard locknuts aren't suitable for this purpose.

Where are grounding bushings required?

The National Electrical Code (NEC) Articles 250.64 & 250.92 require the use of a grounding bushing. In addition, NEC Articles 344.46 & 300.4(G) require a bushing with conductors 4AWG or larger. 1. Prepare conduit by squarely cutting the conduit to the desired length and deburring conduit end.

What is the purpose of a grounding locknut?

Used to connect threaded conduit or connector to a threadless opening in a box, enclosure, or fitting. Provides a secure connection for grounding applications.