70e and cable tray work

[cjkline]

Have any of you had to deal with installing additional wire in a cable tray that already has power cables, (440v, 3 phase) in the tray? I have been told that 70E will not allow a worker to be in the cable tray while the power cables are energized. A good deal of our tray cannot be accessed by ladder or bucket truck and the only way to pull the cable is to be inside the existing tray. I was unable to find this covered in the 70E book, but I may have missed it, can anyone shed some light on this issue?
thanks

 

[edavis2293]

70e and cable tray

70e and cable tray

I know of no manufacturer that will permit us getting in a cable tray, whether it has cable or not. The tray is not listed for the weight. Tray supports are normally not over 20' apart but can be 24', depending on the tray. We usually use a pull rope to two people stationed in the piperack and pull the cables, either in straight runs or using Greenlee rollers for lengthy pulls. If cables are smaller than 4/0, they do not have to be in a single layer and can be pulled and laid atop the existing cables. We have had to be quite innovative but none of the solutions involve getting in the tray.

I have seen guys in the trays plenty of times with no damage but, if you do it, use the lightest people you have and tell them to stay off the cables and walk or crawl the side rails.

 

[jim dungar]

What part of the cables in your tray are exposed and energized? If you are not allowed near insulated energized conductors than you are not allowed near extension cords.

I know of no cable tray manufacturer that would take any responsibility for a person "inside" the tray.

 

[Smart $]

... A good deal of our tray cannot be accessed by ladder or bucket truck and the only way to pull the cable is to be inside the existing tray. ...

FWIW, person "in" tray is an ill-advised option. In addition to not being designed for, some manufacturers explicitly label the tray as not for support of personnel. Moreover, I assume this tray is some noteworthy height above the closest working platform below. How do you plan to implement [an approved] fall arrest system for the person "in" the tray.

Exactly why is your tray is not accessible by ladder or bucket truck? How was it installed? Were current obstacles installed after the tray? Have you considered using (renting, leasing if need be) an aerial lift platform? Some of the boom lifts made by JLG and others have articulating jibs, making them better suited in getting over and/or around obstacles.

 

[cjkline]

Sorry, I was not clear enough when asking the question....is anyone using an "energized work permit" when pulling cable through the tray with it being energized, and I think that the recommended procedure, 70E, is to keep your body below the tray, so that if you were to be shocked you would not fall onto the energized cable.

It looks to me that you cannot be above the tray on walk boards or without a guard to keep you from falling into the tray.

As far as extension cords go, they are to be protected by GFCI's and being at circuit breaker level they do not have the potential for arc flash.

Anybody have any first hand experience with this issue?

thanks

 

[jim dungar]

Sorry, I was not clear enough when asking the question....is anyone using an "energized work permit" when pulling cable through the tray with it being energized, and I think that the recommended procedure, 70E, is to keep your body below the tray, so that if you were to be shocked you would not fall onto the energized cable.

It looks to me that you cannot be above the tray on walk boards or without a guard to keep you from falling into the tray.

As far as extension cords go, they are to be protected by GFCI's and being at circuit breaker level they do not have the potential for arc flash.

Anybody have any first hand experience with this issue?

thanks

The cable in the tray is insulated therefore touching it is not exposed electrical work. Contacting this energized insulated cable is not any different than touching an extension cord.

Any time you are working above 6', you need the proper fall protection. Cable tray is not consider a work platform.

GFCI's only offer protection against line-ground faults, they do not prevent an arc from occuring between line and neutral.