Parallel to Single feeder run

[myjbrc]

Have a 500' run to 400 amp sub-panel (200' inside/300' outside). Due to voltage drop, I am hesitant to run 600mcm to whole way. Instead the first 200' of the run we have run parallel 2 1/2" for parallel 250mcm to a j-box in the basement. The remaining 300' will be outside. I am planning on taking (1) 4" conduit with 600mcm (300') the remainder of the way to the subpanel. The parallel 250's splices will splice to single 600mcm in the j-box via hi-press or Polara lugs. Is there any code stating I cannot splice parallel feeders to a single feeder at a properly sized junction box?

 

[480sparky]

...... Is there any code stating I cannot splice parallel feeders to a single feeder at a properly sized junction box?

Nope. The paralleled conductors simply need to comply with 300.3(B)(1) and 310.4 is all.

 

[augie47]

agree... no problem
I played the numbers a bit and it appears you could reduce the wire size a little and still mainatin a 3% VD.

 

[bob]

If applicable, don't forget to increase the size of the EGC.

 

[winnie]

...Due to voltage drop, I am hesitant to run 600mcm to whole way. Instead the first 200' of the run we have run parallel 2 1/2" for parallel 250mcm to a j-box in the basement. ...

Keep in mind that the voltage drop of 2x250kcmil is greater than that of 1x600kcmil

-Jon

 

[Cold Fusion]

Have a 500' run to 400 amp sub-panel (200' inside/300' outside). Due to voltage drop, I am hesitant to run 600mcm to whole way. ...

A couple of silly questions:

Is it 480V, 240V, 208V, 575V?
Three phase or single phase?

cf