# Paging system



## wendon (Sep 27, 2010)

I'm going to be installing the cabling etc. for a paging system in a private school. I don't do this sort of thing very often. What are the codes involved? If the system is operated over 30 volts, it falls under a different class, correct?


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## erics37 (May 7, 2009)

Is there an existing speaker system you'll be tying your stuff into? Or will it be all new speakers and a paging amplifier?

I believe most of the paging amplifiers I have put in are labelled Class 2 wiring for their output but don't quote me on that. You'll have to look at your amp to see. Anyway a Class 2 circuit is a class 2 circuit, doesn't matter that it's running at 70 volts. Free air wiring.


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## wendon (Sep 27, 2010)

erics37 said:


> Is there an existing speaker system you'll be tying your stuff into? Or will it be all new speakers and a paging amplifier?
> 
> I believe most of the paging amplifiers I have put in are labelled Class 2 wiring for their output but don't quote me on that. You'll have to look at your amp to see. Anyway a Class 2 circuit is a class 2 circuit, doesn't matter that it's running at 70 volts. Free air wiring.


All new equipment. It'll have two outdoor horns, one indoor horn, and probably about 25 ceiling speakers. It probably would make more sense to go with the 70 volt system. Is interference more of a problem with the higher voltage systems?


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## LoVolt134 (Dec 14, 2012)

18-2 or 16-2 cable should be fine, depends on length of runs. If your worried about interference, get shielded cable, and tie the drain into the amp.


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## A Little Short (Nov 11, 2010)

LoVolt134 said:


> 18-2 or 16-2 cable should be fine, depends on length of runs. If your worried about interference, get shielded cable,* and tie the drain into the amp*.


Would that be the kitchen or bathroom drain, and wouldn't that gurgling sound be loud when run through the amp?:jester:


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## LoVolt134 (Dec 14, 2012)

A Little Short said:


> Would that be the kitchen or bathroom drain, and wouldn't that gurgling sound be loud when run through the amp?:jester:


Ground the drain properly and you'll never hear that gurgle!


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## jeffmoss26 (Dec 8, 2011)

70v RMS is 100v peak to peak, so some places require it to be in conduit, which is why 25v systems came into play.

This is a good read.
http://www.crownaudio.com/media/pdf/amps/138905-1_10-05_constant_voltage.pdf


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