Wallace Perimeter Security SPEEDGATE - Page 84

84
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INSTALLATION INSTRUCTIONS FOR OPTIONAL VEHICLE DETECTORS
Installaon of Vehicle Detecon Ground-Loop Systems
8. If an automac exit loop is required, a third detector relay will be required. If an automac
exit loop is required, a third detector relay will be required (not supplied by Wallace Perimeter
Security). This auxiliary detector should be powered from terminals #1 and #2 and wired as a
N.O. contact to terminals #1 and #3.
9. Choose a sealant carefully to match the applicaon and the pavement type. Hard seng
epoxies should not be used with asphalt. Cauon should be observed when using hot sealants,
as high temperatures can damage or destroy wire insulaon. Please refer to the jurisdicon/
state’s department of transportaon specs for trac light loop sealant.
9.1 When properly applied, the sealant should completely cover the loop wire(s). Since the sealant
forms a barrier between the wire and the environment, it is essenal that the wire(s) are
completely covered. See Figure 20 for the proper end result.
9.2 There MUST be no voids which might allow water to collect within the slot. The water will
freeze and expand during freezing condions. Freeze/thaw cycling will eventually push the
loop wires up and out of the slot, resulng in a loop failure.
10.
Loop Diagnoscs
The following tests cannot guarantee a funconing loop, but failure of either test means that
the loops are denitely suspect, even if sll funconal at the me of tesng.
10.1 TEST 1 - Resistance of the loop and loop lead wires should not exceed 4.0 ohms.
10.2 TEST 2 - The resistance to earth, as measured with a 500V “Megger”, should be 100 Megohms
or more. Loops may funcon at less than 100 Megohms but will not be reliable (e.g., when the
ground is wet from rainfall). Low resistance indicates broken or moisture-saturated insulaon.
This is common if inappropriate wire insulaon has been used.
Figure 20. Proper Sealant Applicaon