fire alarm- phone line

[TexasMaster]

Got something thrown in my lap today.. the responsibility of running the telephone line(s) to a fire alarm panel. Admittedlly through some misunderstanding in our contract.. blah blah.. its our baby now. The building is 55000sq ft add on to an existing beer distribution warehouse. NO big deal except in this situation the fire alarm panel is about 700ft from the telco room, top it off the the super doesnt demand conduit but says hes almost certain it needs it. I expect the fire marshall will have a little stronger opinion. My question is.. is the conduit required and is the cable required to be anything special (planned on just a cat5). Ceilings are exposed steel web joist all the way. My appologies, i just cant seem to come across anything in the nec on the subject, just thought someone out there might be a good quik reference

 

[TexasMaster]

and yes i had planned to stub up on each end to protect from physical damage

 

[massfd]

Check with the fire marshal about the conduit, the panel should supervise the phone connection. The telco lines between the CO and the building are not in conduit so they may not require it. Also I would ditch the cat.5 and run cat.3, the extra twists in cat.5 make the electrical length of the run longer than 700 feet. The telco provides dial tone on cat.0 so runing cat.5 gains nothing.

 

[TexasMaster]

I hear you on the extra length/twists, i just usually go with cat5 on everything from phone to data, every since, at least in my area cat 5 is actually cheaper than anything else, if we can even find anything else, due to the demand of everyone else following that suit.

I think the concern of the super was if the phone line burned before it got a chance to notify or something

 

[TexasMaster]

well thanks for the input.. i'll check what the fire marshall wants.

 

[dhalleron]

Unless it's a local thing, I've never seen a code requirement that phone lines for the fire system be in conduit. The fire alarm code just simply calls it a phone line without much other detail and that line seizure is required.

 

[Stallzer]

Your Fire Inspector should have no jurisdiction as to whether or not the cable is installed in EMT, but I'd check with the Electrical / Building inspector. The Fire Marshall only needs to ensure that the system is installed up to local code and that it operates properly.

 

[esobocinski]

Check with the fire marshal about the conduit, the panel should supervise the phone connection. The telco lines between the CO and the building are not in conduit so they may not require it. Also I would ditch the cat.5 and run cat.3, the extra twists in cat.5 make the electrical length of the run longer than 700 feet. The telco provides dial tone on cat.0 so runing cat.5 gains nothing.

It's true that running Cat 5 gains nothing at phone frequencies, but Cat 3 is no better. Cat 3 and Cat 5 are both spec'd for 9.38 ohms / 100 meters DC resistance (and 100 ohms impedance at 1 to 100 MHz). The geometry of twisting is such that the wire length difference is trivial between Cat 3 or Cat 5 twist lengths, and it doesn't matter anyway since the AWG is actually not important to the spec as long as the manufacturer meets requirements for electrical characteristics.

 

[hurk27]

I hear you on the extra length/twists, i just usually go with cat5 on everything from phone to data, every since, at least in my area cat 5 is actually cheaper than anything else, if we can even find anything else, due to the demand of everyone else following that suit.

I think the concern of the super was if the phone line burned before it got a chance to notify or something

One would think that before that happens (in red above) the detection system has long been tripped and the call went out already:happyyes:

But then there are cases where lightning struck the phone line and started the building on fire but I dont think the counduit would have helped much in that case

 

[MAK]

. Also I would ditch the cat.5 and run cat.3, the extra twists in cat.5 make the electrical length of the run longer than 700 feet. The telco provides dial tone on cat.0 so runing cat.5 gains nothing.

I am not that familiar with telco stuff but is there an issue with the phone line being longer than 700 feet? :?

 

[hbiss]

I am not that familiar with telco stuff but is there an issue with the phone line being longer than 700 feet? :?

No considering that it comes from miles away before getting to the building.:dunce:

-Hal

 

[George Stolz]

:dunce:

Was that really necessary? :thumbsdown:

 

[hbiss]

Was that really necessary? :thumbsdown:

Perhaps a bit harsh, but a little thinking before asking a question goes a long way.:happyyes:

-Hal

 

[George Stolz]

A little thinking without research or asking questions leads to many of the misconceptions we deal with on a regular basis. Perhaps you'll go a little easier on the next "stupid" question that comes along, eh?

 

[texie]

No considering that it comes from miles away before getting to the building.:dunce:

-Hal

Actually, it is a fair question. There are definately "loop" limits for a POTS circuit. Depends mostly on wire size and other factors. And those long distances (miles) from the CO are not just a plain old pair of wires. There are all kinds of things done to increase the effective loop length.

 

[iwire]

I think the concern of the super was if the phone line burned before it got a chance to notify or something

But putting it in pipe would really not do much. I saw some UL testing and pipe in a fire added just about 20 SECONDS to the life of a cable.

You would have to run it outside the building or encased in concreate to really make it last longer and once you get to the buildings demark point it would be open wiring again anyway.

 

[kwired]

Question - Does the fire alarm have a dialer or is a continuous monitoring over the phone line?

Continuous monitoring would alert of trouble immediately even if it was a loss of phone company line somewhere away from the facility.

 

[del91574]

You hardly ever see leased lines anymore outside of legacy systems, or at least in my area of the country.

We do have plenty of municipal ties, however with the large facilities we're on, we typically will see an Eschelon/Lonworks based network or as those have started to phase out, a lot more TCP/IP based setups.

 

[hbiss]

Actually, it is a fair question. There are definately "loop" limits for a POTS circuit. Depends mostly on wire size and other factors. And those long distances (miles) from the CO are not just a plain old pair of wires. There are all kinds of things done to increase the effective loop length.

The limit for DSL is around 18,000 feet so POTS can be much longer depending on wire size. You will rarely see anything that long today though because of the practice of using fiber to supply local neighborhood hubs rather than all copper originating at the CO. So not only is another 700 feet chump change, since it is 4 pair cable you could quadruple the pairs up if it makes you feel better. In more than 40 years in the telephone business I have never seen a problem due to excessive POTS loop length, but then again I'm not in a rural area.


-Hal

 

[kwired]

The limit for DSL is around 18,000 feet so POTS can be much longer depending on wire size. You will rarely see anything that long today though because of the practice of using fiber to supply local neighborhood hubs rather than all copper originating at the CO. So not only is another 700 feet chump change, since it is 4 pair cable you could quadruple the pairs up if it makes you feel better. In more than 40 years in the telephone business I have never seen a problem due to excessive POTS loop length, but then again I'm not in a rural area.


-Hal

Like you said you are not in a rural area. Many places still do not have DSL because of distance. The only way we get high speed internet is via wireless sources.