secure cabling 300.11

[eatapeach]

Trying to figure out if an independent support wire is used to support cable shall it it be secured at each end and what does secure at each end mean? Attached to structure and the ceiling grid?

300.11 Securing and Supporting.

(B) Wiring Systems Installed Above Suspended Ceilings. Where independent support wires are used, they shall be secured at both ends. Cables and raceways shall not be supported by ceiling grids.

(2) Non–Fire-Rated Assemblies. Wiring located within the cavity of a non–fire-rated floor–ceiling or roof–ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided and shall be permitted to be attached to the assembly.

The 2017 Commentary states this:
Independent support, and securing both ends of the support wire, do preclude a connection to the ceiling grid on one end.
The word Preclude basically means makes it impossible so which is it ? Secure both ends or is it impossible? How would it be secure if you didn't attach it to the grid?

 

[VEBill]

"...what does secure at each end mean?"

If an electrical cable is to be supported by a support wire, then the electrical cable would seem to need to be clamped at each end (for tension), otherwise the electrical cable might sag from the support wire in places.

All this implies the horizontal runs. The drops to the boxes or devices on the ceiling grid would be different.

Please wait for others to chime in.

 

[waross]

Wiring Systems Installed Above Suspended Ceilings. Where independent support wires are used, they shall be secured at both ends.

I read this as the cable support system must be secured at both ends.
I am thinking basket tray. You can't use a short section of basket tray that is free to swing on the support wires.
Seismic concerns.

Bill
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"Why not the best?"
Jimmy Carter

 

[eatapeach]

No basket tray. The cable is supported on J hooks from a #12 wire. It makes sense to tie both ends however I am getting mixed interpretations. I have several Building Officials to read it as secured and it should be tied to the ceiling grid while others think the cable passing thru the J hook provides the support on the end. The NEC I thought was very clear that it's required to be attached on each end until I read the commentary.

 

[Richard B]

After your user name you have (Military)
If this is a DOD project then you must meet both the requirements of the NEC and UFCs (Unified Facilities Criteria). From the information given I am not sure if this is a power or telecom installation, however in either case what you are describing probably does not meet the UFC criteria.

On the WBDG (Whole Building Design Guide) website reference
UFC 3-501-01 Interior Electrical Systems. Section 3.6 Raceway and Wiring.
UFC 3-580-01 Telecommunications Interior Infrastructure Planning and Design.