Straping or supporting low voltage cable

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We sometimes install low voltage cable (plentum type 18ga. 2cond.) for motion sensors to control building lights. we install this above drop ceilings.How often should this be secured or straped or can it be layed right on top the drop ceiling?what code rules apply to the instalation of this?
Racker
 
While there have been changes, the new rules don't say what the CMP intended them to say. 725.7 permits you to lay cables on top of the tiles as long as the tile can still be removed. 725.8 does not apply above lay-in ceilings. These sections need to be reworded to require that all of the cables be supported from the building structure. It is my opinion that this was the intent of the changes, however the code wording does not come close to supporting this intent.
Don
 
Support of Low Voltage Wire

Support of Low Voltage Wire

As a rule of thumb one really oughta do supports and avoid putting cabling directly on any ceiling. The problem I usually see is that fluorescent lights and other devices may cause interference and/or overheating. Also if it is placed on the ceiling it is almost always an open invitation for all other wiring to be run with reckless abandon. Try to put a support every 5 feet, but in some cases you could probably push 10 feet if there is no place to support it to.
 
I know that there are inspectors who will not allow you to lay your cable directly on ceiling tiles regardless of how the code reads, but can you zip tie low voltage cable to drop ceiling grid hangers ? I see it all the time in Mass. my employer always tells me that you can. I think he maybe wrong.I looked in article 800 & 760 did not see any thing saying you can not. When I look at article 300.11 (2) it basically says you can not. So what the deal?
 
Most inspectors forbid laying of any cable directly on the ceiling grid/tiles.
For supporting multiple runs in a bundle, use a j-hook that attaches to the t-bar hanger wires. I have never had an inspector fail a final for using ty raps either.
 
I agree with Don, that the Code isn't worded as nicely as we'd like, however in the areas I practice, the inspectors don't allow cable on the tiles, further, they don't allow cables to be fastened to the ceiling support wires unless you can show that the ceiling system is listed for supporting cable also. I specify that the cabling must be supported independently of the ceiling system, and tied to the building structure.

Jim T
 
skorper said:
Most inspectors forbid laying of any cable directly on the ceiling grid/tiles.
For supporting multiple runs in a bundle, use a j-hook that attaches to the t-bar hanger wires. I have never had an inspector fail a final for using ty raps either.
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We must be the lucky ones because we just failed for this exact thing. We used cable ties all over and was told that cable ties are for tying cable bundles not supporting the cable.
I tired to explain that the wire is only 18/2 and has very little weight. He said I needed to use a support that is for wire.
Any ideas as what to use?
 
Caddy/Erico has a great slection of j-hooks and bridle rings that can attach to ceiling wire. Check your local electical distributor (Graybar for example) they should have a good supply of these or can ge them in short order.
 
Thanks. Our local supplier, Turtle & Hughes had 2" bridle rings. Larger than I need, but that is all he had in stock. I would have much rather had the 1.5", but whatever it takes to pass.
 
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