Feeder Tap Section 240.21(B)(1)(4) - Explanation

[highleygroup]

Can someone give me some explanation of 240.21(B)(1)(4) and its intended use???

Can I get a clarification of "field installations..." it would seem that (4) contradicts with (3) above.....

Would (4) prohibit a 50A tap off of a 1600A bus provided we are less than 10' and also terminate in a 50A OCPD.

 

[don_resqcapt19]

If your tap conductors leave the enclosure where the 1600 amp bus is located, then the tap conductors would have to have an ampaity of at least 160 amps. There is no conflict between (3) and (4), just an additional restriction is applied in (4) for tap conductors that leave the enclosure.
Don

 

[highleygroup]

which enclosure are we talking about - the enclosure (ie..conduit) the 1600 amp bus is located or the physical room in which the bus is routed through

 

[don_resqcapt19]

The enclosure where the tap conductor is connected to the feeder.
Don