User's Manual

Versus Technology, Inc.
Hardware and Wiring Installation Guide 27
many cases, erratic behavior may be noted. In some cases, equipment damage may
occur. In any case, an electrical code violation has occurred.
To verify that the system is “isolated” from building and electrical
grounds:
Note: It may be helpful to disconnect the collector from the punch-down
block while this measurement is made. This will isolate the sensor wiring
completely.
a) Use an ohmmeter or multimeter set to the 2K (2000)-ohm scale.
b) Clip one probe to the nearest electrical conduit or electrical ground.
c) Touch the other probe to each punch-down block row in turn.
d) Every row MUST indicate an infinite (open) connection. If this is not
the case, the suspect line must be traced to find the accidental
connection to the structure that has been made.
4. Once isolation has been checked, replace the bridge clips on the punch-down block.
4.5 Communication Room Check
There are several items that need to be verified before applying power to the system. Use the
Communication Room Checklist in Section 6.6 to check off each step as it is completed.
4.5.1 Checking the Collector Wiring
A visual check of the collector wiring should find the punch-down block secure and the collector
unit connector firmly seated against the punch-down block connector. See the Collector Voltage
Troubleshooting Flow Chart in Section 5.2 for checking the collector wiring.
Caution: Always test all wiring before connection of system power sources.
The collector network (2-pair) must be tested before the system power is applied to be sure that
wires are not misconnected. Failure to thoroughly test the collector network wiring may result in
equipment damage.
The concentrator and collector devices connect to the 2-pair wiring system using modular
interfaces to allow for easy testing of the wiring before power is applied. It is recommended that
installers be equipped with appropriate USOC cable testers as required to verify the installed
wiring.
Note that 3-pair USOC interconnections may also be used. In this case, the third pair (outermost)
is used in parallel with the second pair to improve power distribution to the collectors.