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Discussion Starter #1
I would appreciate some input from you guys regarding cable tray systems. I do not have much experience with cable tray/cable ladder as we do mostly service work but one of our regular customers has asked us to do the electrical on a building they just purchased.

The building is about 194,000 sqft and we will be installing a 4000A switchgear running to several distribution panels. I think that we will be running around 2000 feet of cable tray from the gear to the panels.

It looks as though we will be needing several runs of tray up to 36" wide and tapering down to smaller sizes over the run.

I have been trying to research different kinds of cable tray and prices but have found less information than I expected. The Cooper B line ladder system looks pretty good does anyone have experience hanging it?

My supply house just deals with Square D and in the Schneider digest the cable tray selection is very limited so I might need to find another source.

Also the job is very rush rush and I have a feeling that the customers are going to throw a bunch of money at me on Monday and want to see it going up this week. Any suggestions please?
 

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Senior Moment
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Tips. A lot of industrial customers require bonding of all connections, read the notes. A square hole punch can save a lot of time.
 

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Discussion Starter #3
Any Opinions about how much cable ladder 5 guys can hang per day or week? I know there are variables but we have good exposed building steel, will be bringing in a scissorlift etc. It seems that some systems are faster to put up than others. does anyone recommend a specific brand or type of cable ladder? I'm trying to figure a rough per foot price at this point for providing and hanging the tray.
 

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It should all go together at about the same rate. 20ft sections held together with 2 square brackets, and 8 bolts seems to be the norm on every type I've been around. The longest part will be putting the brackets together. Will you be using angle brackets attached to walls & beams, or threaded rod & strut

Either way, do as much on the ground as possible. Have spring nuts loaded in the strut, have struts all cut to length ready to go for the guys in the air, plan out your supports before you start hanging. Tray goes together fairly easy as long as you plan it out to keep it as straight as possible. A portable bandsaw is a must for tray, as is a file, or cordless grinder to clean up the edge quick.

As was said before, many places have specific bonding requirements. The plant I work at quite a bit wants a continuous egc run through the tray (usually a 2 or a 2/0), and every second piece of tray attached to the egc.
 

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Time can vary greatly depending in the conditions. In a big open space, 5 guys could easily manage 1500ft in a day. In a crowded building, lots of walls & obstacles, they might only manage 300ft a day.

How will the rod be hanging? Beam clamps make things fast. Other methods might eat up a lot more time.
 

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Talk to your supply house. I just ordered tray for three different projects. 2- week lead time for production.

Tray is like fixtures. It's made to order. You can get basic materials from McMaster Carr and they deliver next day. You will pay a lot more though.
 

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Tool Fetish
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We use and stock Cope aluminum cable tray in 12", 24" and 36" widths and 24' lengths. We use the second from the highest grade of frame rails available because of our cable loading and availability of support structures. 24' lengths have about a two week lead in time. A manufacturers rep will be able to help you to calculate the trays you need better than a supply house.You can't just order tray without designing support systems, cable dimensions and cable weights. You can buy the same looking tray that you will have to support every 5' or you can design a system that only needs to be supported every 20 or 25' depending on the grade of the tray rails and cable weights. We use enough cable tray that I deal directly with the manufacturers rep, no supply houses involved. DON'T cut tray with a bandsaw. It will take forever and be difficult to keep straight cuts. We use worm drive skill saws with metal cutting blades. Also use battery Dewalt 1/2" impact wrenches for thousands of bolts. Also quicker to use small hand deburring tools instead of grinders to clean up the sharp edges. Even need to deburr the factory edges on a lot of tray. Not good to see those spirally pieces of cable jacket on the ground after pulling cables. I think our trays net between $300 and $400 per length.
 

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Section 392.60(A) along with 250.96 require all cable tray systems that support electrical conductors to be electrically continuous and effectively bonded and grounded.
Now this is not every connection- as long as the connected parts are mechanically connected, but you do need bonding jumpers on the parts that are not mechanically connected
392.60 Grounding and Bonding.


(A) Metallic Cable Trays.
Metallic cable trays shall be permitted to be used as equipment grounding conductors where continuous maintenance and supervision ensure that qualified persons service the installed cable tray system and the cable tray complies with provisions of this section. Metallic cable trays that support electrical conductors shall be grounded as required for conductor enclosures in accordance with 250.96 and Part IV of Article 250. Metal cable trays containing only non-power conductors shall be electrically continuous through approved connections or the use of a bonding jumper not smaller than a 10 AWG.

 
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