Wire Cable Trays: Modification and Code Compliance
When it comes to basket-style cable trays, you'd think it would be a simple and straightforward matter to get them to turn in different directions. They're made of heavy-gauge steel wire, so you should be able to just pull out your cable tray cutter, snip out a few strategic rungs and form your bend, right? Wrong – not if you want your installation to meet NEC and UL requirements (and believe us, you do).
Failed inspections not only equal downtime for the facilities that are unlucky enough to be saddled with them, but can also mean delayed payment for the installation contractor – any way you slice it, someone is going to lose out. If you have an upcoming cable tray installation, be sure to take our simple code-compliance advice, and set your project up for a passing grade from the get-go.
How Compliant Cable Trays Go Bad
Further, NEC article 392.5(E) specifies that proper fittings must be used whenever cable trays change direction or elevation. Just as with UL's requirements, this means that you can't change the path of a cable tray by removing parts (like rungs) and bending – instead, you need to add on fittings that not only allow for the directional change, but also maintain the cable tray's structural integrity and grounding path.
Keeping Your Cable Tray Installation on the Right Path
It's pretty easy to see that this takes care of the structural requirements, but when used as specified, Cable-Mgr systems automatically fulfill grounding requirements as well. Under the UL Cable Tray Program (CYNW), Wiremaid cable trays and fittings are classified as equipment grounding conductors, and actually form an automatic and continuous ground path when connected to each other. Cable-Mgr cable tray designs incorporate patented ground/splice loops, which simplify grounding and reduce your overall bill of materials, thanks to the fact that they eliminate the need for additional ground splices. The only pieces of hardware required for proper Cable-Mgr tray assembly are carriage bolts and nuts, which just happen to be included.
A Few Helpful Standards Basics You'll Need to Know:
Under NEC Article 392, metallic cable trays are required to:
For more information on cable tray code compliance, please visit the NEC standards website, or check out UL's CYNW cable tray guide.
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