Continuous support for vertical drops of TC-ER

[LRB]

We are utilizing TC-ER cable dropping out of cable tray to motor disconnects. Bottom of cable try is 14 ft and top of disconnects ranges from 5 to 7 feet. Area is protected from physical damage. Plan to run 2 horizontal struts 1 ft above tallest disconnect and 2 ft below cable tray to secure cable. How do you provide continuous support for vertical runs of cable? At this point the distance between bottom of tray and top of disconnects is > 6 ft. If we stub up with rigid out the top of disconnects to a distance < 6 ft can we use the Exception for TC-ER to transition between cable tray and devices?

Per article 336.10(7)

where the cable is continuously supported and protected against physical damage using mechanical protection, such as struts,
angles, or channels, Type TC tray cable that complies with the crush and impact requirements of Type MC cable and is identified for such use
with the marking Type TC?ER shall be permitted between a cable tray and the utilization equipment or device. The cable shall be secured at
intervals not exceeding 1.8m (6ft)

Exception: Where not subject to physical damage, Type TC-ER shall be permitted to transition between cable trays
and between cable trays and utilization equipment or devices for a distance not to exceed 1.8 m (6 ft) without
continuous support. The cable shall be mechanically supported where exiting the cable tray to ensure that the minimum
bending radius is not exceeded.

 

[MasterTheNEC]

@LRB,

So I assume you are in an "Industrial Establishment" in order to even venture down the road of Type TC-ER.

If the Type TC Cable has been evaluated for the "crush" , it will be-ER listed and labeled and if indeed you are in an "Industrial Establishment" then you are permitted to use the allowances you have quoted.

If you are able to transition from the CT to the utilization equipment and product the continuous support from transition to equipment by what ever logical support necessary to support the application.(Struts, Channels, Etc.). In fact, the last one I did (back long ago) was a transition from ladder tray to a wire mesh tray all the way down to just above the equipment..but your case may dictate differently.

In terms of the exception....depending on the location (above for example) yu may be able to rule out "subject to physical damage"..(check with the AHJ of course) and if not more than 6' from the tray to the equipment...indeed use the exception and use stress relief devices and ensure the bending radius is maintained.....you should be fine.

I am sure others will chime in with other thoughts as well.

 

[LRB]

Master the NEC,

Thank you for your reply. This is an " Industrial Establishment" and the specs called for TC-ER cable which the cable is clearly marked. I am still in the dark on how to "continuous support" a vertical cable drop if the exception is not applicable. Securing the cable is taken care of, but that is not "continuous support". Thank you.