B-41
Cisco IE 3000 Switch Hardware Installation Guide
Appendix B Installation In a Hazardous Environment
Connecting Power and Alarm Circuits
Wiring the External Alarms
The alarm relays on the switch are normally open. To connect an external alarm device to the relays, you
must connect two relay contact wires to complete an electrical circuit. Because each external alarm
device requires two connections to a relay, the switch supports a maximum of two external alarm
devices. This procedure is optional.
Warning
Explosion Hazard—Do not connect or disconnect wiring while the field-side power is on; an
electrical arc can occur. This could cause an explosion in hazardous location installations. Be sure
that power is removed or that the area is nonhazardous before proceeding. Statement 1081
Caution
The input voltage source of the alarm circuits must be an isolated source and limited to less than or equal
to 24 VDC, 1 A.
Note
Wire connections to the power and relay connector, must be UL- and CSA-rated, style 1007 or 1569
twisted-pair copper appliance wiring material (AWM) wire (such as Belden part number 9318).
To wire the switch to an external alarm device, follow these steps:
Step 1
Measure two strands of twisted-pair wire (18-to-20 AWG) long enough to connect to the external alarm
device.
Step 2
Use a wire stripper to remove the casing from both ends of each wire to 0.25 inch (6.3 mm) ± 0.02 inch
(0.5 mm). Do not strip more than 0.27 inch (6.8 mm) of insulation from the wires. Stripping more than
the recommended amount of wire can leave exposed wire from the power and relay connector after
installation.
Step 3
Insert the exposed wires for the external alarm device into the two connections labeled A. See
.
Figure B-28
Inserting Relay Wires into the Power and Relay Connector
1
External device, relay wire A connection 1
2
External device, relay wire A connection 2
202029
RT A
V
A
1
2