Splicing parallel feeders

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rootboy

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We're reusing some armor cable from one of our other plants and it will need to be spliced somewhere in the middle.

This is a parallel 500MCM feed (two armor cables) so both cables get spliced in the middle.

The contractor recommends that both feeders get spliced in the same box and that both sets of leads get tied together in the box (e.g. phase "A" gets tied to the other phase "A").

Personally this sounds like a dumb idea but I can't seem to find where it is not allowed in the NEC.

I'm aware of the other rules:

? They must be the same length
? They must be terminated in the same manner
? They must have the same conductor material
? They must be the same size in circular mil area
? They must have the same insulation type

but is tying them together in the middle specifically disallowed?


Thanks,

John
 
Your later is refering to 310.4. I concur with Winnie, it is just the same as landing parallels in a bus duct tap box or use Clear Taps in a properly sized J box . A to A, B to B etc.
 
I suppose... but I hate to mix the feeders in the middle of a run. If only for ease of troubleshooting purposes.

One thing to consider about tying the feeders together in the middle of a run is that if one set of the feeders were to be disconnected at both ends the disconnected feeders would still be hot.


The good news is that the project lead (a M.E.) agrees with me and we will be doing individual butt splices with cold shrink insulation. This should hermatically seal the connections (which is important since the splice box will be on our roof).


Thanks for your help guys.

John
 
winnie said:
IMHO tying them together in the middle of the run is acceptable but not required. Just think of the conductors on either side of the splice as _separate_ parallel runs.

However I see no significant benefit to doing this, and I don't see this as required.

There was an 80 post discussion on just this topic.
http://forums.mikeholt.com/showthread.php?t=91255

-Jon
Click to expand...

Me neither, and I'm not sure that it wouldn't cause problems in the long run. Besides, why do it that way in the first place?

And thanks for the link to the previous discussion. I had looked around before posting but I didn't see that thread.
 
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