How to install Loop for the Loop Detector?

Time of issue:

2014-02-10 16:39

Source:

All permanent loop installations should be installed in the roadway by cutting slots with a masonry cutting disc or similar device. A 45°crosscut should be made across the loop corners to reduce the chance of damage that can be caused to the loop cable at right angle corners.

Nominal Slot width: 4mm

Nominal Slot depth: 30mm to 50mm

A slot must also be cut from the loop circumference at one corner of the loop 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 numbers of turns of wire are will 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 tree ends are twisted together to ensure they remain in close proximity to one another.(Minimum 20 turns per meter).Maximum recommended loop sensitivity decreases as the feeder length increases, so ideally the feeder cable should be kept as short as possible.

The loops are seated using a “quick-set” black epoxy compound or hot bitumen mastic to blend with the roadway surface.