#14 Fixture Whips on a 20 amp circuit

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JKennedy

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Assuming that this topic had been previously addresses, I searched through out the site and could not find the answer.

The circuit runs from a 20A breaker in the lighting panel, through EMT to a 4? sq box (#12 THHN), drops out of the box wt #12 MC, down a cable tray and into a 4? sq box and converts back to #12 THHN. The # 12 THHN is distributed via ? EMT to 4? sq boxes located within 3? of each fixture.

Question one: If I install one 6? whip for each lighting fixture from a 4? square box located approx 3? from the fixture, can I use #14 THHN from the fixture to the box?

Second Question: The branch circuit feeding the above mentioned light is a #12 MC cable installed in a 36? Cable Tray mounted above a drop ceiling. The cables are installed tight against one another and secured with wire ties. They are not bundled together or stacked on top of each other. Do I need to derate the wires within this cable tray?
 
JKennedy said:
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Question one: If I install one 6’ whip for each lighting fixture from a 4” square box located approx 3’ from the fixture, can I use #14 THHN from the fixture to the box?
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Yes, look at 240.52(B)(2).

JKennedy said:
.Second Question: The branch circuit feeding the above mentioned light is a #12 MC cable installed in a 36” Cable Tray mounted above a drop ceiling. The cables are installed tight against one another and secured with wire ties. They are not bundled together or stacked on top of each other. Do I need to derate the wires within this cable tray?
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No, even if they were considered bundled 310.15(B)(2)Ex5 would apply.
 
Fair enough 240.5(B)(2)...


Is THHN "fixture wire" (T402.3)?

EDIT:
Added code section
 
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celtic said:
Is THHN "fixture wire" (T402.3)?
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That is a resoundingly good point. :cool:

Since THHN is not listed in Table 402.3, then these are not "fixture wires", they are branch circuit conductors. Therefore, 210.19(A)(4) would be the applicable section. Under exception 1 to that rule, #14 conductors could still be used, but the length would be restricted to 18", IMO.
 
Good point, the original poster was not that specific. If the luminaires are recessed cans, then 410.67 allows the whips to be 6' long. (When I saw the 410.67 reference in the exception to 210.19(A)(4), I thought it had to do with cans, and I incorrectly assumed it was in regard to the j-box that's included with the can.)

I'm not really sure what makes cans special? :confused:
 
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