Cable Tray

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george t. everett

Senior Member
Location
New York
At a recent IAEI meeting, Arlington fittings put on a presentation of their products.
They showed their PVC cable tray, saying that up to 40 # 14-2 cables could be installed
in their cable tray without derating. I found this hard to believe, but a local inspector said that because it is cable tray in free air that it is allowed, I need a second opinion.
 

ty

Senior Member
At a recent IAEI meeting, Arlington fittings put on a presentation of their products.
They showed their PVC cable tray, saying that up to 40 # 14-2 cables could be installed
in their cable tray without derating. I found this hard to believe, but a local inspector said that because it is cable tray in free air that it is allowed, I need a second opinion.

Are you talking about this product? :

IMG00846.jpg


IMG00847.jpg


If so, I do not think it can be installed without derating.
We install this product.
The wires have to be 'bundled' when installed.
I've never heard of Not derating when using it.
There is a unit fill for each type of wire installed, but that is for total volume fill.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
The vendor is probably right; however there are several (not particularly onerous) restrictions. There are still fill limits [392.9(A)(2)] and a few layout requirements in 392.11(A).
More important though, there is nothing unique about their tray with respect to this feature.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Although they do mention it being used for "power cables" in their catalog it is listed as a "communication product" where it can be useful.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
it looks alot better than wires hanging all over.
It also is better than drilling 2 1/2" holes all the way across a basement.

But if you need to derate then the most you'll get is 4-12/3 or 4-14/3 cables in there before you'll need to increase your cable size. Seems like a lot of product for only 4 cables, unless of course you want to use larger conductors.
 

RUWired

Senior Member
Location
Pa.
At a recent IAEI meeting, Arlington fittings put on a presentation of their products.
They showed their PVC cable tray, saying that up to 40 # 14-2 cables could be installed
in their cable tray without derating. I found this hard to believe, but a local inspector said that because it is cable tray in free air that it is allowed, I need a second opinion.


George, number of multi conductor cables in a tray is based on inches squared and table 392.9(A)2. You need to know equal dia of cable and width of tray. Derating for multiconductors cables is based on number of conductors in each cable, not number of cables in the tray.I don't know of any exceptions for pvc tray, only pvc wireways.

Rick
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
George, number of multi conductor cables in a tray is based on inches squared and table 392.9(A)2. You need to know equal dia of cable and width of tray. Derating for multiconductors cables is based on number of conductors in each cable, not number of cables in the tray.I don't know of any exceptions for pvc tray, only pvc wireways.

Rick

Actually derating is based on the number of CCC's not the number of conductors in the cable.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
How is this product listed? Is it per the UL Cable Tray Standard?

Someone more familiar with UL may find something I did not, but the UL listing number shown on their advertising pae (E161207) is listed as conduit and cable hardware (same as their straps are listed)
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Someone more familiar with UL may find something I did not, but the UL listing number shown on their advertising pae (E161207) is listed as conduit and cable hardware (same as their straps are listed)


Augie, given the information available, and as an inspector, would you require derating for cables installed within this stuff or not?
 

RUWired

Senior Member
Location
Pa.
The description online shows this as a cable way. Since there isn't a section on this to calculate the number of cables, i would think the cable way should have the maximum amount of cables listed inside the cable way so the inspector and electrician can determine the amount even after the initial installation.

Rick
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Augie, given the information available, and as an inspector, would you require derating for cables installed within this stuff or not?

Rob, I have seen it one time and I required derating, but to be honest, neither the E/C or I thought about the possibility of "cable tray".
Desipte some opinions given here by others :), I do try to give E/Cs any advantage we can USING the Code.
One reason I enjoy this site is it often opens that opportunity. When cable tray was first mentioned here I thought that might be one of those "doors", but from what I have found so far, based on the UL E161207, I would have to call for derating.
As George Everett mentioned it doesn't make sense not to if you derate in the joist.
If someone shows me it's listed as a cable tray I would have to look at it a different light but considering the complexity of 392.9, I hope they don't :)
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
CAM, yep! that's what I found. I don't see any mention of "cable tray" so as of now to me it's a "hanger" and derating for bundling applies
 
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