In-screed Heating: Installation

Installing Safe-t-SCREED wiring through screed in Australia can be performed in 11 steps:

1.    TCP17 Coax Screened Dual Core Cables are suitable for attaching to a light weight galvanized 50-100mm square mesh laid flat on the existing concrete sub-floor. The dual Core Cable has only one cold tail at one end, simplifying the installation.
The Heating Cable must not be cut or shortened and must be RCD protected. A licensed electrical contractor must provide connections in accordance with Australian standards paragraph 4.22 of AS 3000.

2.    Cables are calibrated to provide 160w/m2 density rating at a spacing of 100 mm. (This coincides with every second row of the 50 x 50mm mesh. Plastic cable ties can be used by clipping every 500-600mm along the mesh.
Cables must not cross or touch each other or contact thermal insulation.

3.    Cables are selected by measuring the area to be heated in m2. This is multiplied by 1000 and then divided by 100. This calculates the cable length required at 100mm spacing. Select the cable with the closest length that matches the calculated size. Where two cables are used for a large area, the connections can be connected in parallel at the thermostat or junction box.

4.    Position cables to avoid water pipes, baths and permanent fixtures that will be installed on the finished floor with nails or similar fixings. Perimeter cables should be run with 50mm minimum distance from walls and fixtures.

5,    Sketch the location of: cables, remote sensor conduit, cold tail joint to heating cable and the junction box with neutral and active connections. Provide an installation copy for any future modifications/ renovations etc.

6.    The single cold tail screen goes to household "Earth". Being a Dual Core Cable, the cold tail also has twin cores for the neutral and active connections. 30ma ELCB or Residual Current Device protection is required.

7.    Where total wattage loads are 3500w or less, the supplied 16a AE-Y310 Insbud Control can be connected direct to the cable cold tail. For loads exceeding 3500w, contactors are used with the cable cold tail terminations housed in a wall junction box positioned approx. 300mm above floor level.

8.    Always follow the guide of the contactor supplier when sizing.

9.    Remote Probe: A 10-20mm ID conduit sealed at both ends, should run down the wall from the controller and a radius bend applied to run 1-2 meters out on the existing floor surface from the wall, midway between two cable runs. This facilitates future replacement of the probe if required.

10.    Provide a conduit for each cold tail to be taken to the wall location of the controller.

11.    Allow 8 weeks minimum from concrete pour before applying heat to the slab. This should be done gradually over 2 weeks.

For more detailed information about installing our underfloor / under tile heating, you can download the installation guide in pdf format from our downloads section.

Inscreed Heating: Safe-t-SCREED Installation #1

Side view of how the Safe-t-SCREED heating cable is placed in the screed

Inscreed Heating: Safe-t-SCREED Installation #2

Safe-t-screed in-screed heating cables laid on mesh to be embedded in screed