How to Feed Small Loadcenter from 400 AMP Fused Disconnect

[Leo1]

Any suggestions on how to feed a small 5kVA 120/240VAC transformer from a 400AMP, 480VAC, 3-phase fused safety disconnect switch NEC compliant and economically? Placing a large junction box or wireway below the fused safety disconnect switch with terminal blocks for continuation of 400AMP conductors to their load and tapping smaller conductors to feed the small transformer(per 240.21) is a solution. However, the fused safety disconnect switch is approx. 3' high and the junction box to accommodate 600kcmil conductors with terminal blocks is also near 3' high which is placing the top of the fused safety disconnect switch near 7' high to keep the junction box cover off the ground a few inches not to mention the cost of the large junction box, terminals and labor. Getting an extra set of lugs in the fused safety disconnect switch is not doable I have been told.

 

[kwired]

Why isn't different lugs in the safety switch doable?

Is there room in the switch enclosure for other termination means?

reduce the size of wireway or j box needed by using smaller paralleled conductors instead of single large conductors, at least between the switch and the splicing enclosure?

 

[Cow]

Without looking it up, you will need to follow the tap rules and most likely set some sort of OCPD right after the tap as soon as possible.

Taking a stab at it, I'd probably do an Ilsco IPC connector----wire sized for the tap----fused disconnect---transformer.

 

[cpinetree]

Maybe something like a homac #CSB 750-3?
http://www.tnb.com/ps/fulltilt/index.cgi?check=Y&part=CSB7503
It only goes down to a 1/0 for the small conductor, you may need to reduce that again, with a 2 port connector to feed into your disconnect.