Lighting

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Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
I am running lighting for an industrial ball mill building. 4,225.03 square feet x 1.7va X1.25 (assuming workshop? Table 220.12)

Based on outside dimensions) lighting and general loads require 8,978 va with at least 4 Of 20 ampere branch circuits.

There will be 8 lights on one circuit paralleled on one switch. Led bulbs only 8.5 watts each or less than 0.56 of an ampere for entire lighting circuit

My question is that if trying to figure optional feeder size such as using #10 AWG THHN with 40 amperes at 90 degrees Celsius

Then, after ampere ampacity correction for temperature and terminating at 60 degrees I would be left with 26.1 amperes available for this conductor. # 10 AWG wire at 60 degree yields 30 amperes. Ambient temperature at 105 degrees for 90 degree wire yields correction reduction of 0.87% further reducing this conductor to 26.1 ampere

This seems fine for feeder I want to bring to junction box but I’m confused if I’ll have to run #10 wire to lights or could I reduce wire at this 4 square metal box to #14 AWG only for the conduit containing lights using less than 1 ampere.

The breaker being used to protect circuit couldn’t be 26.1 because this is not standard so I could go down to 25 amperes if I decide to supply receptacles or go up to 30 amperes for just lighting.

Question if I tap 14 AWG lighting wires to 10 AWG Feeder at box as explained above won’t there be a fire hazard or violation if current exceeds 14 awg wire limit for lights but upstream breaker at feeder is rated for higher 25 or 30 ampere?

If you were to say use 14 awg all the way from Breaker to feeder to lights then how would this meet the requirements of 4 branch circuits based on total general lighting and appliance load from building area in square feet x VA? Thanks
 
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