Quick Hits

PART V — BONDING

EPISODE 18 — Bonding at Services and Communications Systems 1kva (270.90, 270.92, 270.94)

Slide 1 — Hook "New Part! Bonding — starting with the general rule and the specific requirements at service equipment."

Slide 2 — 270.90 & 270.92

• 270.90 General: bonding has to be provided wherever necessary to ensure electrical continuity and safely carry any fault current that could occur.

• 270.92(A): all raceways/cable trays/gutters/service cable armor enclosing service conductors, PLUS all enclosures containing service conductors (meter fittings, boxes, etc.), must be bonded together.

• 270.92(B): bonding jumpers are required around impaired connections (reducing washers, oversized/concentric/eccentric knockouts) — standard locknuts/bushings alone don't count as bonding, just mechanical connection. Acceptable bonding methods: bonding to the grounded conductor, wrenchtight threaded connections, tight threadless couplings, or other listed bonding devices.

Slide 3 — 270.94 Communications system bonding

• An Intersystem Bonding Termination (IBT) is required outside enclosures at service/metering equipment and at building/structure disconnects — must be accessible, hold at least 3 intersystem bonding conductor terminations, not block equipment access, and be securely mounted/listed.

• Alternative: connections to a properly sized aluminum/copper busbar (min. ¼" × 2") meeting specific mounting/connection rules.

• Not required at all if communications systems aren't likely to ever be used in/on the building.

Slide 4 — Quiz + CTA Q: "An Intersystem Bonding Termination (IBT) must have terminal capacity for at least how many intersystem bonding conductors?" A) One B) Two C) Three D) Five

✅ Answer: C — 270.94(A)(2): capacity for at least three.

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