304UM0001 Rev 00
PD160 Enhanced Series User Manual
Page: 26 of 39
5.5 Loop Installation
All permanent loop installations should be installed in the roadway by cutting slots with a masonry
cutting disc or similar device. A 45° crosscut shou ld be made across the loop corners to reduce the
chance of damage that can be caused to the loop at right angle corners.
NOMINAL SLOT WIDTH: 4 mm
NOMINAL SLOT DEPTH : 30 mm TO 50 mm
A slot must also be cut from the loop circumference at one corner of the loop, leading to the roadway
edge to accommodate the feeder.
A continuous loop and feeder is obtained by leaving a tail long enough to reach the detector before
inserting the cable into the loop slot. Once the required number of turns of wire are wound into the slot
around the loop circumference, the wire is routed again via the feeder slot to the roadway edge.
A similar length is allowed to reach the detector and these two free ends are twisted together to ensure
they remain in close proximity to one another (Minimum 20 turns per metre) Maximum recommended
feeder length is 100 metres. It should be noted that the loop sensitivity decreases as the feeder length
increases, so ideally the feeder cable should be kept as short as possible.
The loops are sealed using a “quick-set” black epoxy compound or hot bitumen mastic to blend with
the roadway surface.
300 mm
300 mm
+/- 2 m depending on road width
1
m
1
m
Min Distance Apart - 2 m (Road width = 2 m)
- 3 m (Road width = 4 m)
Max Distance Apart – No Limit
Figure 5.1 Adjacent loops connected to different detector modules
