240.21(B)(1)(4) - Taps Not over 3 m (10 ft) NEC-2014

[victor.cherkashi]

1. What does is exactly mean "for field installations" in paragraph 240.21(B)(1)(4)?


2. In which case I must to provide tap conductors at least one-tenth of the rating of the feeder's OCPD?


3. Is it permitted what I did on my sketch? (conductors less than one-tenth of 500A feeder/riser)

 

[infinity]

Your installation would fall under the 10' rule which means that the tap conductors must be at least 50 amps. You're installing them in the field so if the conductors leave the enclosure (the tap box) then the 10% rule applies.