Quick Hits

EPISODE 5 — Uses Permitted: Locations & Conditions (310.10(A)–(F))

Slide 1 — Hook "New Part! Installation — starting with WHERE different conductor types are actually allowed to go."

Slide 2 — Dry, damp & wet locations

• Dry locations: any listed conductor/cable type works.

• Dry AND damp locations: a specific list of types — FEP, FEPB, MTW, PFA, RHH, RHW, RHW-2, SA, THHN, THW, THW-2, THHW, THWN, THWN-2, TW, XHH, XHHW, XHHW-2, XHHN, XHWN, XHWN-2, Z, or ZW.

• Wet locations: needs to be moisture-impervious metal-sheathed, one of a specific list (MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, XHWN, XHWN-2, ZW), or otherwise listed for wet-location use.

Slide 3 — Sunlight, burial & corrosive conditions

• Direct sunlight exposure: needs to be insulated AND listed sunlight-resistant, covered with listed sunlight-resistant tape/sleeving, OR bare/uncovered where bare conductors are otherwise permitted.

• Direct burial: must be a type identified for that specific use.

• Corrosive conditions (oils, greases, vapors, gases, fumes, liquids that could harm the conductor/insulation): must be a type suitable for that specific exposure — this is why THWN's nylon jacket makes it commonly rated for gasoline/oil exposure.

Slide 4 — Quiz + CTA Q: "A conductor exposed to direct sunlight, that is bare or has non-sunlight-rated covering, is permitted only under what condition?" A) Never permitted B) Where bare conductors are otherwise permitted elsewhere in the code C) Only in dry climates D) Only for conductors over 4/0 AWG

✅ Answer: B — 310.10(D)(3): bare/non-rated covering is fine specifically where bare conductors are otherwise allowed.

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