Cable Tray in Tent Structure over Public Swimming Pool

[Flashability]

I have an unusual situation here. Owner is putting a semi-permanent tent around an existing public swimming pool. In the event of a hurricane, plan is to remove side-wall and roof tent fabric and leave open aluminum structure to ride out the storm. Tent supplier is providing lights, exhaust fans and fabric inflation air compressors but will need power for them. My plan is to supply power into tent from a new NEMA 3R panel mounted outside the tent on the side of the existing CMU walled building. Original plan was to run branch circuits underground through a couple 6? sleeves through the concrete footing; however, workmanship in installing footing and sleeves rendered this option unusable. Plan B is to run power overhead into the tent through the sidewall. For this purpose it would be nice to utilize a cable tray; in fact, running a cable tray around the inside of the tent and dropping down with RMC at the loads would be a good way to distribute power throughout the tent. Reading through NEC Article 680, cable tray is not specifically prohibited, but it?s also not listed as allowable either. Article 680 does allow the use of armored cable which could be run in cable tray rather than tray-cable, but that seems rather expensive and it would be sure to raise aesthetic objections if it?s not run through conduit at the loads. Does anybody have any useful insight here? Does anybody have a better approach? Thanks!

 

[petersonra]

My guess is anything left above ground like lights gets whacked by the hurricane. They need to be removable as well.

 

[steve66]

Will you meet the required clearances from a pool for all that stuff? (By stuff I mean lights, fans, wiring, etc.)

It sounds crazy to me - installing electric on a "semi-permenant" structure over a pool.

 

[Flashability]

petersonra:
According to the developer, the tent manufacturer does plan to provide some means to easily remove electrical devices. Electrical contractor is to run power to junction boxes and tent people will take it from there.

steve66:
I agree, but we do what we?re paid to do. (I?ve checked the Yellow Pages and we?re not listed under ?weird projects?; I?m not sure why every project we get seems to have all these bizarre twists and turns.:?) According to the AutoCAD drawing, the tent side walls are around 25 feet from the front of the pool, about 12 feet from the pool along the sides and most of the back and about 7? feet along the back side of the diving area. (T-shaped pool and tent. Hopefully, it will actually get assembled in the correct place.) So meeting the clearance requirements should be feasible. In looking at Part 1 of the two part Mike Holt Article 680 write-up sent out in the newsletter a while back, it looks like in the diagram of receptacle clearances from a pool; the 6 foot spacing is the hypotenuse of the triangle formed by the horizontal and vertical distance between the pool and receptacle. Is that correct? (Not super critical here since we have the horizontal distance and we intend for receptacles to be mounted at about 48 inches above pool deck. But, that?s a good thing keep in mind during construction.)

There is a state regulation that restricts the installation of light fixtures directly above an outdoor pool (I think we?d need to consider this an outdoor pool for that purpose.) Luckily, the tent people decided to design the lighting and have them all around the perimeter; meeting the state required minimum lighting levels for a public swimming pool is their responsibility.

In thinking it over, I?m not sure I?m comfortable with distributing power inside the tent with cable tray; I don?t believe it would stand up very well to a hurricane. I can use NEC Article 680 to justify this to the developer. (Can anyone offer any insight on outdoor cable tray in hurricane areas?) We don?t really have that many branch circuits, so I think running them all the way in rigid-metal makes the most sense.

 

[steve66]

steve66:
I agree, but we do what we?re paid to do. (I?ve checked the Yellow Pages and we?re not listed under ?weird projects?; I?m not sure why every project we get seems to have all these bizarre twists and turns.:?) According to the AutoCAD drawing, the tent side walls are around 25 feet from the front of the pool, about 12 feet from the pool along the sides and most of the back and about 7? feet along the back side of the diving area. (T-shaped pool and tent. Hopefully, it will actually get assembled in the correct place.) So meeting the clearance requirements should be feasible. In looking at Part 1 of the two part Mike Holt Article 680 write-up sent out in the newsletter a while back, it looks like in the diagram of receptacle clearances from a pool; the 6 foot spacing is the hypotenuse of the triangle formed by the horizontal and vertical distance between the pool and receptacle. Is that correct? (Not super critical here since we have the horizontal distance and we intend for receptacles to be mounted at about 48 inches above pool deck. But, that?s a good thing keep in mind during construction.)

There is a state regulation that restricts the installation of light fixtures directly above an outdoor pool (I think we?d need to consider this an outdoor pool for that purpose.) Luckily, the tent people decided to design the lighting and have them all around the perimeter; meeting the state required minimum lighting levels for a public swimming pool is their responsibility.

In thinking it over, I?m not sure I?m comfortable with distributing power inside the tent with cable tray; I don?t believe it would stand up very well to a hurricane. I can use NEC Article 680 to justify this to the developer. (Can anyone offer any insight on outdoor cable tray in hurricane areas?) We don?t really have that many branch circuits, so I think running them all the way in rigid-metal makes the most sense.

I haven't looked up the clearances, but its good to know someone has checked them. I think its definately good the lights are around the permimeter, and not directly above the pool.

I know what you mean by the weird projects - I seem to get a lot of those too.

I don't have any suggestions on the wiring methods, but I also think it would be good if the lights were removable.