Multicore loop

      Multicore cable loop

Use this alternative loop method to set a reliable road loop after the road surface has been completed.




Author  :    Huw Jones

Builder management

Lets face it, if you could trust the groundworkers to put the loop in the driveway, you would bite his hand off. It is an extra half day on site for a messy job.

You have known the installation needs a road loop. You have told the main contractor you will need to lay it before they lay the driveway wearing surface is laid. Yet, they go ahead and complete the drive without a call.

But even if you supply the materials, he wiil want you to stand there and tell him what to do.

The multicore technique only requires the ground worker to run 2 more ducts in addition to the cross drive at the pier. Ideally, the ducts are put in the hogging at the same time the curb stones are laid.

Shouldn't be a problem ......... should it?

NYY cable


An induction loop is a number of turns of a single core cable set in the road surface. The area enclosed by the loop is the detection area. Detection sensitivity is proportional to the detection area and the number of loops of cable.

Loops set directly in the road surface are at risk when the road surface quality is poor. Cracks in bitumen or concrete roads are likely to cause loop damage. Road repairs often cause more stress to buried loops.

Running the cable

This alternative method to setting a loop requires two ducts across the road. The cable runs through one duct, loops around, and back through the other duct. Both ends terminate in the control box. The detection area is the distance between ducts by the road width.

The cable can be run directly in the road foundations (not in ducts) or in the sand course below paving blocks. But the road may be laid months before the automation is completed, and by different contractors.

Laying ducts is easy to specify to road contractors. The same ducts can also be used for other power and control cables.


The 5 way terminal block can be located in a control panel, or in a separate box with the loop module. It needs to be accessible.

The right hand connection to the loop module is shown in terminal 3. In this case only the first three turns around the loop are used. By selecting the number of loops.

Connect inside the control box as shown. Connect the loop module to position 1 for loops over 16m2 area, position 2 for loops over 8m2 area, position 3 for loops over 4m2 area, and position 4 for smaller loops. Use a direct burial NNY cable Connect the loop module

Interconnections made in the control panel