Pub. 42004-139D
GAI-Tronics 700 Series Page/Party
®
Systems
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Static Charges
In many normal installations, a static ac voltage may be read from the conductors of the page and party
line circuits to ground. In many cases this voltage may be as high as 50 volts or more. This voltage is
induced into the circuits by capacitance to the ac power circuit (generally carried in the same cable, and
also from power cables paralleling communication cables). This voltage is inconsequential and can be
ignored. Problems would only occur if one side of the page or party circuit becomes grounded.
Audio Voltage
In a properly operating system, audio voltage read across any of the page or party circuits (L1 or L2) is
0.5 to 0.75 volts ac on peaks when an audio signal is present: i.e., someone speaking into a handset. The
voltage is proportional to the loudness of the person’s voice using the handset.
One Inoperative Station in a Working System
Except for a wiring error, an inoperative station indicates a defect in the amplifier at the station. This is
checked quickly by installing a spare amplifier or exchanging amplifiers with a properly operating station.
Special Note Regarding Installation
GAI-Tronics Corporation Page/Party
®
system equipment does
not
, in normal operation, produce arcs,
sparks or heat that would ignite industrial gases or dusts. Many standard GAI-Tonics products are
approved by Factory Mutual (USA) and certified by CSA (Canada) for intended use in specified Division
2 areas if properly installed and maintained.
Proper installation is defined as (1) mounting and wiring per factory directions without unauthorized
modification and (2) following all requirements of the U.S. National Electric Code (NFPA - 70) or the
Canadian Electric Code (CSA Standard C22.1). Installers must be familiar with these codes and consult
them as required. The most applicable parts of the N.E.C. code are in articles 500-503. The most
applicable parts of the Canadian code are in Section 18. Some, but not all, significant points are:
1.
Conduits in a Class I, Division 2 area to or from a non-hazardous area or an adjacent Class I, Division
1 area must have approved seals in the boundary.
2.
Conduits or raceways in a Class II, Division 2 or Class III area must have dust seals at entrances to
dust-tight equipment and at boundaries to other areas unless such conduits or raceways are also dust-
tight.
3.
Explosion-proof (Division 1) equipment may be installed in a Division 2 area but must have the same
conduit and cable seals as if installed in the corresponding Division 1 area.
4.
Sealing of multi-conductor cables or conduits containing multi-conductor cables in Class I, Division 1
or 2 areas must be around each conductor of the cable - except where type MI cable is used.
