Primary Feeder Tap

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tmillard

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Hi...

I am currently working on a project and am running into some issues I thought you could help me with.

There is a 13.2KV double ended loop on site with (3) sets of S&C unfused switches. The loop is composed 750kcmil conductors and fused on both sides. Therefore if a feeder burns out you can isolate it and replace it.

I wanted to tap one of the S&C switches (on the unswitched side) to feed a 2000KVA transformer. The xfmr is fused on the primary side (in the cabinet) and is about 600' away. I am also feeding it with 750's. The local inspector has raised a flag saying I violated code by not installing overcurrent protection right at the S&C switch. He is quoting 230-220. I am looking at 240.101 (B) which states you don't need overcurrent protection as long as the tap conductor is protected feeder over current device.

Any thoughts?

Thanks,

Tom Millard, P.E.
 
Assuming that the overcurrent device for the 750's in the "loop" arrangement is correctly sized I'm not sure that the 750's that are feeding the x-fmr would be considered a tap.

Wanting to see both sides of the story, what edition of the NEC is your inspector giving you code sections from? I checked back to the '99 edition and don't see a 230-220.

Pete
 
Tom,
Even if it is a tap, that is a conductor not protected at its ampacity, as long as the conductor is outside, it would be premitted by 240.21(B)(5).
Don
 
Tom,article 240.21 only covers circuits 600 volts or less.Article 230 only covers utility supplied conductors and equipment.

Article 240.100/101 covers your spliced/ tapped conductors at the source of the loop feed(s).

Personally i don't think it's a very good idea to put a transformer onto a loop feed without individual switching. You will be doing a lot of unnessesary switching and locking out to isolated it.Typically these are put on the switched/fused side of s&c switch.
Rick
 
tmillard said:
Hi...

There is a 13.2KV double ended loop on site with (3) sets of S&C unfused switches. The loop is composed 750kcmil conductors and fused on both sides. Therefore if a feeder burns out you can isolate it and replace it.
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What is going to interrupt the power if the cable faults. Are both risers fed from an overhead line?
 
Tap Update

Tap Update

I just received word from the inspector yesterday that he wants a fused S&C switch regardless. The loop is protected with fuses so these would protect the cable.

This is the coming from the same person that made us put battery units throughout a manufacturing facility because he felt the new emergency generator could fail and no egress lighting would be provided.
 
Inspectors are not supposed to make up the rules as they go. You may have to go to his boss. Of course, you will probably be on his bad side forever.
 
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