HV J-Box sizing

[ch_0124]

I am trying to size a J-BOX in which we are gonna splice a 5kv connection to a bus bar and i'm wanting to make sure that we get the backplate far enough off the bus bar and the lugs off the cover of the box. The nec has information on 600v and below but does it say anything about how far the metal cover would have to be off the lug if 5kv. Rule of thumb is one inch for every thousand right. These connections will be taped as well.

 

[Redsplicer]

art. 490 NEC 70 has a table, which for 5 kV I think is 6 Inches phase to phase, and phase to ground

please look it up to be sure

 

[Nick]

we are gonna splice a 5kv connection to a bus bar

Please explain why you would splice 5KV in a j-box like this. Just curious.

 

[RHJohnson]

gonna splice a 5kv connection to a bus bar and i'm wanting to make sure that we get the backplate far enough off the bus bar and the lugs off the cover of the box.

Why the busbar? You must mean you have 3 or more cables.......if only 2, forget the busbar.

 

[masterinbama]

Sounds more like a hi-hat box for terminating 5KV to a piece of gear. As for taping 5KV terminations at bus bars I have had the best luck with Raychem heat shrink tape

 

[ch_0124]

hv splice box

hv splice box

the box is actually the like the midway point for a pull we're doing. the pull is engineered to be pulled almost 2000 feet from a new power plant to an existing plant and the box is gonna allow us to pull both directions and simplify the pull a lot. i just was wandering if the code book had a table or anything showing clearances from 5kv to a metal cover

 

[charlie]

Why not use a prefabricated junction box? We use a 3' X 5' pullbox with a heavy fiber lid and an open bottom for the minimum size for making primary splices. Be sure to locate your junction box in a pedestrian only area and specify a skid resistant surface. :smile: