GAI-Tronics Associated with 600-ohm systems Extended Range Page/Party System Manual - Manual (Page 7)

Pub. 42004-324A
Extended Range Page/Party
®
Systems Page: 7 of 10
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Static Charges
In many installations, it is normal to read (measure) a static ac voltage 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 or
from power cables paralleling communication cables. This voltage is inconsequential and can be ignored.
Problems will 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 and L2) will
be approximately 0.5 to 0.75 volts ac on peaks when an audio signal is present, i.e., someone speaking into
a handset. The voltage will be 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 either a spare amplifier, or exchanging amplifiers from a known operating
station.
Special Note Regarding Installation
GAI-Tronics Corporation 600-ohm Page/Party
®
system equipment is NOT approved for use in classified
areas, although under normal operation it does not produce arcs, sparks or heat that would ignite industrial
gases or dusts.
Proper installation is defined as (1) mounting and wiring per factory directions without unauthorized
modification, and (2) following all requirements set-forth by the U.S. National Electric Code (NEC),
articles 500-503, the National Fire Protection Agency (NFPA - 70), or Canadian Standards Association
(CSA) Electrical Code per CSA Standard C22.1. Installers must be familiar with the applicable codes, and
observe all established requirements. The most applicable parts of the Canadian Standards 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.