I have a question regarding Article 680. Specifically 680-10. It tells us that Underground wiring shall not be permitted under the pool or within the area extending 5 feet horizontally from the inside wall of the pool. There are a few exceptions for pool related equipment. It goes on to say well, ok, if you don’t have the room to run it outside of the 5 foot band then go ahead and do it but use these wiring methods. A little bit of a contradiction I would say. You shall not do X but, if you can’t comply then go ahead and break the general rule!
Anyway, here is the situation. A job has a water feature between two buildings. The Water feature consists of a “stream” That is about 5 feet wide 6 inches deep and runs about 450 feet where it dumps into a “pond” that is about 200’ by 100’ and a maximum of 4 feet deep. At the pond end of the feature is an equipment vault with all the pumps and associated equipment. The problem I am seeing is the site distribution. It consists of 4 circuits at 12.47KV 1 12.47KV emergency feed and a comm. Duct bank consisting of 14 4” Carlon Multi Guard conduits. This has to cross under the water feature as designed to feed the building on the opposite side.
My line of thinking is like this. In the scope of article 680 it states the provisions of 680 apply to decorative pools and fountains. Would we consider this “water feature” a decorative pool? If so running any power under or within 5 feet of the water feature is a clear violation. If the city sees it this way the whole site distribution is going to have to be re designed at major expense. I need to bring this up in a presentation we have to do and I don’t want to be wrong. (We don’t have the job yet. We have to do a presentation and I am considering bringing this up under critical issues) what does the forum think? Is it not an issue?
Nick

Nick,
I would simply ask your local AHJ if said 'water featutre' constitutes a 680 consideration.
Perhaps bodily immersion is key?

Nick,

This sounds like it would be considered a fountain, which, as you know is regulated by Part 1 of 680. As far as the Underground Wiring Locations, it may seem contradictory, but it does provide for relief in instances just like yours. On the other hand, my experience is limited to 600 volts, and 18" for a NM raceway seems a bit shallow for MV feeders. Could you double the depth?

Depth will not be a problem. The 15KV stuff will be concrete encased and about 5 feet below grade. Comm will be 3 foot. It’s all going to come down to how the AHJ classifies the water feature I guess. It does seem to be in the fountain category as the scope of that pat of the article includes reflecting ponds. I’ll just have to wait. Plans just recently went into plan check. Will see if they catch it.

Nick,
If these raceways and conductors are utility owned, then the NEC does not apply. I don't know if there is anything in the NESC about this type of installation.
Don

Don,
These are not utility owned. The Campus is primary metered at the central plant and customer owned 12KV is distributed from there.

Nick

What city/county does this take place in?
A few years ago, we encountered something similiar in S.B. County, on a 7.2kv system install. Ductbank consisted of (6) 5" db-120, concrete encased pvc, with 3- 7.2 feeders.A depth of 7' to top of encasement was required per plan. Trench box, and storm pumps for the high water table were required. At the time, couldnt understand the 7' depth, when 5' is usually standard. Never a mention of this increased depth.

Months later, long after the original project was complete, they "added" a rather large fountain and pool over this area.

Just makes you go hmmmmmmm....

NS4Me

By the way, Im curious. Do you work for MM ?

The job is in the jurisdiction of the City of San Diego. I kept thinking where in San Bernardino County would you have a water table that High? Then I realized you must mean Santa Barbara County. And yes, you got the employer right.

Just curious guys.
As I said, I only work below 600 volts. However, table 300.50 only requires 30" for direct burial cables up to 22 kV.
Does anyone actually bury them this shallow.
BTW, is 5 ft. a common depth?

Redsy,
I haven’t dealt with direct burial cables myself. As far as the subject of the 5 foot burial depth goes the following is my opinion only. I think that that depth is common for two reasons. One is engineers usually spec at least 36” of coverage. And two, 5 to six feet is the right elevation to hit the windows in the manholes that are required for these systems. Usually 6’X8’X8’ deep. (or so)

Some specs call for excavation depths of 59 inches {as opposed cover depth}—apparently shoring is required for 60 inches or more.

Seems to me that 680.10 applies to "pools" since it didn't add the words "and similar installations", nor did it add words "body of water", so it doesn't seem to me that your water feature falls under the scope of 680 for any other item than pools.
The closest thing in 680 to your water feature would be fountains -- and as defined in 680.2, it wouldn't have to have any energized parts to fall under the category of "Permanently Installed Decorative Fountains and Reflection Pools".