Feeder Cable; Ground Installation - Allmatic A1H-U Manual De Instrucciones

7.4. Feeder cable

It is important to pay attention to the installation of the feeder cable between the Loop Detector and
the loop. The groove between the corner of the loop, to the edge of the road, should follow same
recommendations as for loop installation.
Note: The feeder cable must be twisted at least 20 turns per meter all the way from the corner of
the loop, to the Loop Detector and be fixated right up to the Loop Detector terminals.
The maximum recommended length of the feeder cable is dependent on the wire gauge. For long wire
lengths, the cross section of the cable should be bigger.
Cable gauge [mm
0.75 mm²
1.50 mm
2
2.50 mm
2
The following rules must be followed to ensure reliable detection:
• The feeder cable should not run in parallel with other electrical wires. A minimum distance of 10 cm
between feeder wire and other cables is required.
• Excess feeder wire should be cut off to suitable length. It must never be coiled up or stuffed inside the
control cabinet.
• The feeder cable must be fixated all the way from the corner of the loop to the Loop Detector.
Movement of the feeder cable during operation can lead to false detections.
• Feeder wires from adjacent Loop Detectors, should not be placed in close proximity of each other.

7.5 Ground Installation

The loop wire can be installed in most road surfaces, but it is important to ensure a stable foundation.
Installation in asphalt or concrete are the most common and will give the most stable performance. It is
important that the loop wire does not move when the surface layer is under stress from vehicles. If this
happens the Loop Detector can create false detections. A stable wire installation is especially critical
when the Loop Detector is operating at high sensitivity settings or with ASB enabled. Wire movement
can for example be created by following the conditions:
• If the surface layer is too thin to support vehicle load
• If the groove is cut all the way through the surface layer
• If the foundation beneath the surface layer is not stable e.g. soil, sand or uncompressed gravel
The loop can be installed together with rebar (reinforced concrete) as long as the loop is placed on
top of the iron bars. If electrical heating of the road surface is needed, it is recommended to use 2-wire
cable types.
] Cable gauge [AWG]
2
Maximum recommended length
18 AWG
15 AWG
13 AWG
Rev.00 - 09.2021 | A1H-U Single Loop Detector | © 2021 | Allmatic
20 meter (66 feet)
40 meter (131 feet)
50 meter (164 feet)
17