Quick Hits

EPISODE 2 — Supervised Installations and Objectionable Current (270.5, 270.6)

Slide 1 — Hook "Today: when engineers get more flexibility, and what to do when grounding causes problems instead of solving them."

Slide 2 — 270.5 Supervised Installations

• If a facility's design is under engineering supervision AND qualified, documented-experience persons install/maintain/monitor it, grounding/bonding requirements can be determined by those qualified persons instead of the article's prescriptive rules. This is a big deal in Article 270 — a lot of medium/high-voltage work happens at supervised industrial sites.

Slide 3 — 270.6 Objectionable Current

• Grounding/bonding has to be arranged to PREVENT objectionable current (stray current flowing somewhere it shouldn't).

• If multiple grounding connections cause objectionable current, you're allowed to: discontinue some (not all) connections, relocate connections, interrupt the conductive path, or take other approved fixes — as long as the effective ground-fault path requirement is still met.

• Normal ground-fault currents and required grounding connections are NOT considered "objectionable" — you can't use this section as an excuse to skip required grounding.

• Special case: a listed isolator device is allowed in the EGC path to block DC current from cathodic protection systems while still passing AC fault current.

Slide 4 — Quiz + CTA Q: "Can normal ground-fault current ever be classified as 'objectionable current' to justify removing a required grounding connection?" A) Yes B) No — abnormal conditions like ground faults are excluded from that definition C) Only over 5000V D) Only for DC systems

✅ Answer: B — 270.6(C) explicitly excludes ground-fault currents from being called "objectionable."

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