Code & NEC
When are bonding bushings required?
Evaluate raceway continuity, concentric knockouts, service equipment, and fault-current path.
The objective is a reliable low-impedance fault-current path; the required method depends on where the raceway is used and how it terminates.
Evaluate
- Is this service equipment, a feeder, or a branch circuit?
- Does the raceway terminate through concentric/eccentric knockouts or a listed bonding means?
- Are reducing washers, flexible sections, or impaired threads involved?
- What fault current could the path need to carry?
What to verify
- Service bonding provisions and raceway bonding requirements in the adopted edition.
- Listing of enclosures, hubs, locknuts, bushings, and bonding jumpers.
- Size and termination of any bonding jumper.
Common mistakes
- Adding a plastic bushing and assuming bonding is addressed.
- Relying on loose locknuts or paint-covered surfaces.
- Using a bonding bushing without completing the jumper path.
Field check
- Inspect contact surfaces, tighten listed fittings, verify jumper routing/termination, and document continuity before energizing.