Quick Hits

EPISODE 8 — Direct Burial and Support Requirements for MV Cable (315.36, 315.40)

Slide 1 — Hook "Today: what direct-buried medium-voltage cable has to look like, and how cable gets physically supported at terminations."

Slide 2 — 315.36 Direct-burial conductors

• General rule: must be SHIELDED, identified for direct-burial use, and installed per 305.15.

• Exception No. 1: nonshielded multiconductor cables rated 2001V-2400V CAN be used if they have an overall metallic sheath or armor — that sheath/armor must connect to a grounding electrode conductor, grounding busbar, or grounding electrode.

• Exception No. 2: airfield lighting cable in series circuits up to 5000V, powered by regulators, is permitted to be nonshielded (FAA Advisory Circulars provide more detail on this specific application).

Slide 3 — 315.40 Support

• Type MV cable terminated in equipment, or installed in pull boxes/vaults, must be secured/supported — using metallic or nonmetallic supports rated to handle the cable's weight, listed cable ties identified for securement/support, or other approved means.

• Spacing: no more than 5 ft from terminations, and no more than 6 ft between supports generally.

Slide 4 — Quiz + CTA Q: "Type MV cable support intervals from terminations are capped at what maximum distance?" A) 3 ft B) 5 ft C) 6 ft D) 8 ft

✅ Answer: B — 315.40: intervals not exceeding 5 ft (1.5 m) from terminations.

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