Feeding a piece of equipment via Cable Tray

[tim89s]

I need to feed a 208v 50 amp 3 phase load via cable tray. Actually, I need to feed about 80 different pieces of equipment from a cable tray but, I just wanted to throw out one example. After reading the code here is what I came up with. I will run TC cable from the panel through the cable tray until I am above the piece of equipment. I will then set a box on the side of the cable tray and run the TC cable into it. I then plan on dropping SO from the box with the appropiate cord connector. After reading 400.7, I am thinking I need to install a receptacle in the box and have the SO plug into it. I would of rather hard wire into the box, am I missing an exception or other code that would allow me to do that. Also, can I attach a support grip to the cable tray for the SO? If not how would I support the SO in accordance with 400.10. Thank you, Tim

 

[wireguru]

how far from the tray to the equipment? Unless you cant support it at 6ft intervals, why not just drop the tray cable to the equipment?

edit:
after reviewing the code sections (2005 -dont have 08 infront of me) to confirm what I already thought, your SO cord drop is a pendant -as such it doesnt need an attachment plug and supply via a receptacle outlet. As far as supporting the cord, wire mesh strain relief out of the box, or a seperate wire mesh grip attached to the tray then the cord loops over into the box.

 

[eric9822]

I think you are overcomplicating this a bit. There is no need to transition from tray cable to SO cord or include a receptacle. Run tray cable in tray as you plan. At an appropriate point in the tray, transition the run of tray cable to rigid conduit that continues to the equipment.

 

[tim89s]

The tray is 12' AFF

 

[tim89s]

I think you are overcomplicating this a bit. There is no need to transition from tray cable to SO cord or include a receptacle. Run tray cable in tray as you plan. At an appropriate point in the tray, transition the run of tray cable to rigid conduit that continues to the equipment.

The customer requested cord drops.

 

[wireguru]

I have a question about 'support'. TC-ER can extend in umlimited lengths, but must be supported in 6ft intervals. What constitutes support? Does the cable have to be rigidly affixed to something? Or 'held' by something?

For example. could you drop 12ft of TC-ER from the tray, with a wire mesh grip @ 6ft, with a length of wire rope attaching the wire mesh grip to the tray for support?

 

[wireguru]

The customer requested cord drops.

ah. heres this again then

after reviewing the code sections (2005 -dont have 08 infront of me) to confirm what I already thought, your SO cord drop is a pendant -as such it doesnt need an attachment plug and supply via a receptacle outlet. As far as supporting the cord, wire mesh strain relief out of the box, or a seperate wire mesh grip attached to the tray then the cord loops over into the box.

 

[eric9822]

ah. heres this again then

after reviewing the code sections (2005 -dont have 08 infront of me) to confirm what I already thought, your SO cord drop is a pendant -as such it doesnt need an attachment plug and supply via a receptacle outlet. As far as supporting the cord, wire mesh strain relief out of the box, or a seperate wire mesh grip attached to the tray then the cord loops over into the box.

How is it a pendant if he is attaching it to a piece of equipment?

 

[wireguru]

How is it a pendant if he is attaching it to a piece of equipment?

needs connector at the bottom of it, and cord and plug on the equipment. (implied, but I should have spelled it out -thank you) but does not need a male plug on the drop and a receptacle up on the tray.

 

[eric9822]

needs connector at the bottom of it, and cord and plug on the equipment. (implied, but I should have spelled it out -thank you) but does not need a male plug on the drop and a receptacle up on the tray.

Ok. I agree with that

 

[tim89s]

If I attach a strain relief at the box would the box need to have threaded hubs or would a locknut suffice? Would I also need a strain relief at other end of the SO?

 

[eric9822]

If I attach a strain relief at the box would the box need to have threaded hubs or would a locknut suffice?

CGB with a locknut.

 

[wireguru]

Ok. I agree with that

I just wish I was the guy selling him the 1000ft of SO cord and 80 pairs of connectors :grin:

For your 50A 208V 3ph machine -if its 4 wire, dont forget about the hubbell CS8364C and CS8365C these are 3ph 4 wire CS twistlocks (like the ones used for spider boxes except three phase, 4 wire) and are a great alternative to the much more expensive pin and sleeve where environment permits.

 

[tim89s]

CGB with a locknut.

When I think of CGB, I think of a connector for SO cord. Are you talking about a CGB with strain relief attached to it? Would I also need a strain relief at the other end of the cord? Appreciate the tip on the twistlocks.

 

[eric9822]

When I think of CGB, I think of a connector for SO cord. Are you talking about a CGB with strain relief attached to it? Would I also need a strain relief at the other end of the cord? Appreciate the tip on the twistlocks.

For a twelve foot drop I would use a CGB with a strain relief at the tray level. I don't see any value for a strain relief at the floor level.

 

[wireguru]

this type of CGB -with wire mesh. Please disregard my OSHA unapproved improper illegal use of an outdoor box in lieu of a proper pendant box.

 

[weressl]

I have a question about 'support'. TC-ER can extend in umlimited lengths, but must be supported in 6ft intervals. What constitutes support? Does the cable have to be rigidly affixed to something? Or 'held' by something?

For example. could you drop 12ft of TC-ER from the tray, with a wire mesh grip @ 6ft, with a length of wire rope attaching the wire mesh grip to the tray for support?

Use a cable channel drop from the tray to the ground, as close to the target connection point as practical and the TC-ER can bridge the gap in air. The TC-ER cable is not for moveable equipment subject to continuous and repeated flexing but can withstand vibrations of a stationary equipment normaly associated with motor driven loads. Simple CGB will suffice.