"Low Voltage" PA System Wiring?

[mdshunk]

I'm doing some retrofit and new work on a commercial project. Some of it involves relocating and adding to the PA system (overhead speakers, volume controls, and the like). I'm kind of puzzled now. Since most commercial PA systems operate at 70 volts, this is not a low voltage system by definition. However, most PA work is wired just like a low voltage system (exposed connections at the transformer on the speaker, low voltage rings for volume controls, no conduit, Belden cable instead of a recognized cable for higher voltages, wire gauges less than #14, no fusing, etc.) How am I really supposed to wire a code compliant 70 volt PA system? Are "cans" available for the speaker to contain the connection? Do I have to run conduit or greenfield now that there's a code objection to cable in commercial dropped ceilings? I've done some PA work in the past, but this is the first time that it has really sunk in that this is not a low voltage system. I'm sure other areas of the country are stricter on this matter, so I thought I'd ask for the details here. Thanks.

[Wgoodrich]

They often use the higher voltage due to such distances this lower voltage must run. Per Code any voltage over 50 volts is considered in the first three chapters of the NEC. Chapter Eight for communication wiring refers you back to Chapter three when it comes to over 50 volts and subject to physical damage.

The cable you use for communications must be rated for communications use. However be aware that wire is also rated as high as 300 volts.

The higher voltage does not change the wiring methods unless subject to physical damage.

Read all of Chapter 8 of the NEC. This should help you grip this subject. Notice it refers you back to Chapter 3. Junctions must be in a box if over 50 volts.

Hope this helps

Wg