Suspension of Low Voltage Wiring

[mvernon1]

Ok, so I have been installing low voltage wiring for a while but 99.9 % of all of the new work that I do is in a suspended ceiling environment. I am comfortable with my knowledge in this area.

However we are currently installing in an ancient building that has suspended plaster/sheet rock ceilings. The owner of the building just had it newly insulated and is almost fanatical about us not "mushing" the insulation. So we built a walk way system to get us around the area without damaging the insulation.

We are being paid to remove all of the old wiring (old 25 pairs to anthenol ends) and installing Cat 6 Enhanced for Data and Voice. Client is installing VoIP phone system.

The estimator, being someone of a screw up when it comes to bidding, wants us to just leave the cables lay on top of the suspended ceiling instead of supporting it. When I asked if this was a violation of code, he said no..

So it boils down to this, I know that in a suspended ceiling environment by code low voltage wiring has to be independently supported every 4 to 5 feet.. Etc ET. Al, but I am unsure if this "changes" when you get into a suspended hard ceiling environment.

Can anyone point me to the right direction.. A Website or NEC 2005 section etc to clarify this. I have been caught with code violations because of this idiot before and don't want to go through it again.

Thanks in advance.

 

[LarryFine]

Opinions:

A) CAT-6 is a waste; just use CAT-5e (OK'd, of course). By the time we can use the bandwidth, we probably won't be using copper wire; more likely optical or RF.

2) The estimator isn't the one to ask about codes. Tell him that using CAT-5e will save enough money to cover properly supporting the cabling. Caddy has great LV stuff.

D) Code or not, intentially laying anything on suspended ceiling tiles is just plain sloppy work. I would never hire a company (or employee) that would do it that way.

 

[mvernon1]

While I know that Cat 6 is a waste, unfortunately that is what was spec'd and I have to provide a Level 3 Test result for every cable.

And the estimator used to be a tech/manager of a competetor.. He has 12 years of installation experience. I have 5 and like I said don't perform much work in hard ceiling environments like this one. I install mostly in suspended ceiling and need to know if the "cable needs to be supported every 4 to 5 feet" code regulation is something that would appy to this situation.

I know that installing on tiles is sloppy, and it goes against everything in my personal work ethics not to hang it. Thats why I am asking.. To see if there is any ammunition out there that I can use against him so when I do hang the wire with an appropriate pathing material that I can justify the cost. An honestly I don't want to just walk up to an inspector and ask.

 

[hbiss]

In my opinion a suspended ceiling of this nature is structural due to the weight of the plaster or sheet rock. This is unlike a grid and lay-in tile ceiling where the grid is capable of supporting little more than itself.

We also have to consider access here. You mention a "walk way system" so I assume workers can access the space and move around. Since this is not a tile ceiling there is no reason to worry about cables blocking access if installed properly.

I would treat this like any attic space. I don't see any reason cables can't be laid on the top of the insulation. On the other hand, depending on how high the structure is above the dropped ceiling while inside the space, I might want to install hooks anyway depending on the material and degree of difficulty.

-Hal

 

[petersonra]

I'd be inclined to want them supported as well. Just to keep them out of the way of people walking around up there in the future.

And depending on how many there are, it might look better.

But, i don't see any reason you have to do so to meet code.

 

[tom baker]

Remember for this type of wiring, ie cat 5e low voltage, there is a difference between the NEC requires and what the performance specs, such as EIA/TIA 568 recommend. The NEC does not care if the system does not test out.

 

[tallgirl]

Opinions:

A) CAT-6 is a waste; just use CAT-5e (OK'd, of course). By the time we can use the bandwidth, we probably won't be using copper wire; more likely optical or RF.

Cat6 might be a waste if you're running ordinary data on TCP since TCP will retry the packet on error, but VoIP is time-sensitive and if someone is running VoIP on Cat5e on a gigabit LAN, the risk of data loss is greater than with Cat6.