Cable Supports in Wet-Well

[Flashability]

I'm designing the 480V electrical system for a new storm water pumping station. The submersible pumps are located down a 130' vertical wet-well. The two main drain pumps are 332.5 HP, the two silt pumps are 60 HP, and there?s a small drain pump that?s 50 HP. These pumps will each have a power cable that gets wired back to the MCC and a control cable that gets wired back to the PLC. These cables are supplied with the pumps from the manufacturer. My question is how do we support the cables along the vertical shaft? Do I go by NEC Table 300.19(A)? That table is based on supporting individual conductors in a vertical raceway and we?re dealing with multi-conductor cables without a raceway. Also, does anyone know of a clamp or other support that can be mounted to a concrete shaft that can support the cable weight we?ll be dealing with here without damaging the cables? One design criterion here is that the supports must be removable so the pumps can be changed out.

 

[charlie k.]

I just completed an install where it was a 70' drop. The power cables to the pumps were 4C-2/0 and they were only supported at the top due to fact they will need to be pulled up with the pump if any maintenance was required. We used stainless steel Kellum Grips. At the top where they were anchored we used a 5/8" drop-in anchor with a lifting type eye bolt. The grip was shackled to the bolt. This worked out well in our application. All of the instrumentation was also done this way.


Charlie

 

[Fulthrotl]

Also, does anyone know of a clamp or other support that can be mounted to a concrete shaft that can support the cable weight we’ll be dealing with here without damaging the cables? One design criterion here is that the supports must be removable so the pumps can be changed out.

that would be a design criteria....

a little more info might help... is someone going down in the hole to liberate
the pumps when changeout is in order? if that's the case, it's pretty straightforward.
332 hp? what are you going to feed this *with*?

hubbell makes a nice strain relief that can be knitted around a cable, with a
pin that slides thru the weave to hold it togeather.

now, you are gonna need a 1/2" anchor bolt, say 4" long, in stainless, with an
eyelet, to mount at whatever spacing you deem necessary for the weight of the
cable.

to attach the eyelet on the wall to the finger basket wrapped around the cable,
i'd use a snap link... maybe something like this.....

'cause if someone is going down in a bosun's chair to play with this stuff,
you want it easy to work with.... and climbing gear is easy to work with.

 

[thinfool]

The real answer to your question lies with the pump manufacturer. He should be able to recommend effective wiring methods and supports for your installation.

He will be able to refer you to existing installations that will be helpful.

A cord that will supply 332.5 hp is gonna be a big cord!