MSA MultiGard 5000, Manual

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11
3103-1001 Rev. 0
2.4 Wiring
All wiring to the MultiGard 5000 unit should be made via the plate at the bottom of the unit. Wire
120 VAC, 60 Hz single phase power to the MultiGard 5000 input terminals (see Field Wiring
Diagram) using a minimum of #16 AWG wire. A separate dedicated power source is recommended
to ensure that the unit remains powered when other circuits are shut down for servicing or routine
maintenance. The power source should be a “ground neutral” system. When a step down transformer
is used, an ungrounded or floating system can result. If an isolation transformer is used, the neutral
side of the secondary transformer should be grounded. Always conform to
NEMA and NEC
standards pertaining to installations of this type.
Refer to the wiring diagram showing interconnecting wire between the unit and any other devices.
Relay wiring should be separate from power wiring. Each relay has contacts for normally open,
normally closed and common terminals. Wire to the trouble relays normally closed contact (contact
closed due to loss of power) to provide for fail-safe relay activation on loss of power.
WARNING
Wire Trouble Relay to operate an externally powered device (horn,
beacon, computer, PLC, etc.) using the common and normally closed
contacts for fail-safe operation on loss of power. The Trouble Relay
is an important safety device and failure to wire as specified will
result in no indication should gas detection system malfunction
and/or become disabled.
The horn and local buzzer can be silenced by pressing the HORN ACKNOWLEDGE button on the
Overview screen or through an optional remote horn acknowledge switch (see Field Wiring
Diagram).
CAUTION
Do not connect any system controlled process shut down circuits
until the system has been function checked, calibrated and is ready
for normal operation.
False alarms may occur if this connection is
done before full system startup is completed.