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56#*.
CTi Linear Heat Detector Employing
Intrinsic Safety Barrier for Special Hazard Applications
DS-9284 9/6/16
DESCRIPTION:
Some applications of PROTECTOWIRE CTi type linear heat detection circuits require energy limiting to prevent explosions in
areas classified as hazardous locations. One method used to accomplish this “Intrinsic Safety” is to utilize diode shunt barriers.
Diode shunt barriers consist of zener diodes with current limiting resistors which “shunt” excess voltage spikes to ground.
OPERATION:
The Stahl # 9002/77-093-040-001 is a dual channel barrier used with the CTM-530 interface module to provide protection
in hazardous locations. If excess voltage appears across the detection circuit, the internal zener diodes of the barriers
instantaneously conduct
in the reverse bias direction passing the overflow current directly to earth ground. The replaceable
160mA fuse protects the barrier from reverse polarity connection or from exposure to damaging current levels.
Intrinsic Safety Barrier
Stahl 9002/77-093-040-001
SPECIAL NOTES:
1.
Resistance from barrier mounting strip to earth ground must be 1 ohm or less.
2. ALL intrinsically safe wiring must be isolated from non-safe wiring and routed
in a separate conduit.
3. Non-safe wiring must not cross into safe wiring area segregated by black lines
within the system enclosure.
4. The system ground fault detection circuit is disabled due to the negative leg of the
initiating circuit being connected to earth ground.
5. WARNING: The negative of initiating circuit is connected to earth ground,
therefore a ground fault from the positive leg of the initiating circuit will
result in a false alarm.
6. Suitable for hazardous locations Class I, II and III, Division 1, Groups A, B, C,
D, E, F and G; [AEx ia Ga] IIC hazardous (classified) locations and Intrinsically
Safe for Class I, II & III, Division I, Groups A, B, C, D, E, F and G; Class I,
Zone 0, AEx ia IIC T6 Ga -29°C Ta +49°C.
7. Reference control drawing IL-1622 for installation.
8. The CTM-530 and associated intrinsic safety barriers must be installed and located
outside of the hazardous area.
Intrinsic Safety Barrier
Stahl 9002/77-093-040-0
01
HAZARDOUS
AREA
10K
ZONE 1
1/2W
PROTECTOWIRE
ELR-HD-5-QC
END-OF-LINE
RESISTOR BOX
TEST SWITCH
OPTIONAL
ZB-HD-5-QC
ZONE BOX
CLASS B
INTRINSICALLY SAFE
DETECTION CKT.
TYPICAL
(+)
(-)
Panel Chassis & Barriers
must be connected to
earth ground.
OPTION FACTORY MUTUAL APPROVED ONLY
Zone #1
ELECTRICAL
Nominal Input Voltage 9.3VDC
Maximum Input Voltage 9.3VDC
Internal Resistance 518 ohms per channel +/- 27 ohms
Fuse Rating 160mA rep.#011239
Leakage Current less than 1uA
160
160
1 2
STAHL
3 4
INPUT TERMINALS
FUSE CARTRIDGE
MOUNTING TRACK
FIELD TERMINALS
GROUND TERMINAL
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