Direct bury feeder code requirements

[FishScreener]

Does anyone know of a NEC requirement for horizontal seperation on direct bury conductor?

I am installing a 240V, 3-phase, 20-amp, direct buried feed from a pump to a subpanel at the pump inlet screen. The screen is a mesh drum that rotates, and has a pump to feed a spray bar, that rinses off the moss, etc.

I can find the depth of bury, and requirement for a warning tape in section 300.5.

The contractor wants to know if he can put the conductor in the same trench as the water feed from the screen to the pump.

I have seen them buried under the haunch of the pipe, twelve inches below the bottom of the pipe, in a seperate trench, and level with the spring line of the pipe with 18 and 24-inch seperation.

I have tried figuring it out from the NEC, and am stuck.

 

[7anoter4]

HI FishScreener
I think NEC is not an address for underground cable clearances. I think NESC [National Electric Safety Code] Part 3 may be. See the contents

http://www.constructionbook.com/national-electrical-safety-code-nesc-2002-0738127787/ieee/

In my opinion if the pipe is insulated and is not warm a ft of ground will be enough.
The water pressure is relatively low and you do not expect an explosion possibility, I guess.
Regards

 

[FishScreener]

Thanks for the response.

I got with the "Building Official" yesterday. He was surprised I even asked the question. Apparently they allow the power feeds for the irrigation systems to run in the same trench as the pipe all the time, and don't even requre hazard tape, under the theory that anybody digging around in the field will know that the power feed is buried under the pipe.

That is the standard local practice. If you vary from it they want warning tape.

I'm still going to require the hazard warning tape.

 

[apowerengr]

NESC 354E - non-metallic water pipe no deliberate separation if all parties involved are in agreement. NEC 300.8 could apply depending on how you define raceway? Is the conductor rated for submersed operation? If the water pipe is metallic is it bonded to the supply grounding system so it would conduct a ground fault if one occurred?

 

[FishScreener]

The pipe is a 15-inch dia PIP (plastic irrigation pipe, class 100. Essentially a plastic potable water line pipe with a less stringent spec on the allowable leakage at the gasketed joints, and lower surge pressure rating.

Back when I was building potable water systems, the District I worked for would occaisionally bury, "temporary", (five year intended use) 11,000 kva power feeds to reservoirs and pump stations in the trench with the large, (48-inch+ diameter) steel cylinder water transmission mains. But I was the Construction Engineer, and not the EE that did the designs, and the drawings and specifications were complete and explicit.

The EE that did this design is out of town for another week, and the only direction he gave on the sealed drawings was, "Installation to comply to county standards and the NEC". The Electrician, and General Contractor needed direction to keep them moving.