sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Alarm Cabling in Cable Trays

Does anybody know if there is a specific regulation regarding the coexistence of alarm cabling (fire/buglar/etc.) in a cable tray with data/voice cabling?

I have never seen this done on commercial installations until now; generally, the alarm guys pick a totally independent path, including seperate conduit to the panel location.

My concern in two-fold: I have a situation where the alarm cablers wove between some of the communication cables in and out of the tray. They are running both parallel and right-angle to the communication cable. My first concern is EMI affecting the data cabling, second is the possibility of damage resulting from pulling across the data/voice cables.

I thought I had heard or read somewhere that there was a specific NEC reference on this. Or would this be a jurisdictional issue?

[This message has been edited by Rover88 (edited September 08, 2004).]

we had an alarm guy use our cat5 as pull string and pulled out our cable and put his in the conduit. yeah right!

Don't think you're going to find much in the way of EMI from alarm systems. As far as damage goes, shouldn't do any more damage than pulling a phone or data cable. Personally I don't see an ethics problem either. Now the using your cable for a pull wire is another issue to be settled behind the building.
Bill

should not affect it, but they were being lazy not keeping their cable seperate from yours.

Class 2 and Class 3 Can exist together.

I have seen Inspected and Aproved cable trays. that had CATV,Data, Voice feeds, Fiber, Voice station, Fire, Security, Lighting control, and Line voltage.

The Line voltage was in Flex metal. That had to be physically separed. First Inspector said tied to one side would be good enough but a second inspector required a physical barrier be installed. That was fought and won.

In short Limited Energy can co-exist.
Further Info can be found in the NEC.

The only time I have had a problem with voice lines being close to alarm wires, was when the fire alarm system used a multiplexed loop instead of the good ole fashion EOL circuits. The data being transmited on the polling loop circuit played havoc with our phone system.(Nitsuko DS01 at the time) You could hear the data on nearly every phone in the system. Some burg alarms use multiplexed polling loops as well, but I have never had the situation where a burg panel has given me any trouble.

OSHEA had a regulation about class 3 and class 2 being in conduit/cable trays. I can not find specs right now, but it stated if alarm system had more than 48 VDC they can not be in same conduit and if in cable tray they had to be 3 inches apart. That is the standard we used in the military.

I have had long cable runs of over 1800 feet(main feed within warehouse) with both in conduit, because contractor made us for foire regulations. It caused transient problems and computer/phones did not work all the time. We installed a new feed not in there conduit and allll was well.

I have also had places where alarm company came in behind us and installed in same conduit (short runs though) with no problem.

I would say it is a gamble!!

codes and inspectors can be a bear when dealing with fire-alarm cabling.

i just tell the customer,engineer,architect,whoevers make the decisions. if hearing data on the voice circuits is not an issue go ahead and run en together. that gets you off the hook and probabley an extra when you have to fix the issue.
m