Type W Cable under Ship Deck

[busman]

I have a situation that is a bit unusual. I need to install some temporary equipment on a ship which has a raised deck (about 1" thick) about 10' above the main weather deck. As you can imagine, the underside of this raised deck is a maze of I-beams that support the deck, but there is plenty of open area to run cables. For reasons of the existing connectors on the equipment, I'm being forced to use 4/0 Single Conductor Type W cables with Single Pole Connectors. To keep the raised deck clear, I'm being asked to run the cable down thru stuffing tubes and secure them to the underside of the deck structure (as high as possible in the 10' space to avoid waves that come over the main deck). I'm trying to be very conscious of inductive heating. The penetrations (stuffing tubes) that go thru the deck will have all phase and neutral wires in the same hole. My issue is how to "hang" the cables below the raised deck. I need to keep them spaced so they can use the single conductor in free-space ampacity, but also not get "metal" in the loop for inductive heating. I was thinking of something like Hendrix Cable Spacers but not sure if they would provide enough support. Another idea was a ladder type cable tray - I could get them in aluminum, but they would be supported by welded steel supports. I think with careful routing the cable trays are the best idea and just make sure no steel gets "in the loop". Money is not really an issue, but it MUST WORK on the first try.

Thoughts? And, as always, thanks.

Mark

 

[tom baker]

Suggest using RTRC fiberglass conduit as a sleeve. It’s very rigid, non-corrosive, easy to pull through, and the supporting is minimal compared to PVC. You could use some type of non-inductive strap such as stainless or aluminum.

 

[SceneryDriver]

Use cable tray. As long as the conductors are run together, the material the tray is made from doesn't matter. Neither does it matter if the conductors are run near or parallel to any steel, as long as they're run together. The magnetic fields of the conductors will sum to zero and no heating will occur.

This sounds very much like what we do in the Entertainment industry for temporary power. The link below shows a Rammstein Concert's feeder power - that's all 4/O cable or larger.

https://www.reddit.com/r/oddlysatisfying/comments/yaykhc

We also often lash Cam-Lock conductors together with and run them as a bundle, though you may have ohmic heating issues depending on your load and the distance your cables are bundled; Type W can take quite a bit of heat though.

Ensure your runs are well anchored and that they can't move around - chafing is probably the largest issue on a ship. They can move around a lot in heavy weather.



SceneryDriver

 

[zbang]

(All that above)

Don't worry about bundling individual sets together, "free air" doesn't require individual conductor separation, it requires that they not be enclosed and that air can circulate to remove heat. (Remember that ampacity is based on heat generated and insulation limits, 12g type PF is rated for more than 12g THHN and with a much higher temperature.)