To measure a floor heating mat, you need a meter with a low-voltage resistance measurement function and an insulation resistance measurement function.
- In the first measurement, we measure the insulation resistance. Insulation resistance measurements are performed to test the actual insulation condition of the heating cable. The minimum test voltage of the test is 500 V, the recommended voltage is 1000 V. To perform the measurement, we connect the power wires which we connect under one terminal of the meter, under the other terminal we connect the protective wire. We make a measurement lasting a minimum of 60 seconds. The result obtained should be greater than 100 or 1000 MΩ – depends on the manufacturer’s requirements.
- In the second measurement, we make a low-voltage resistance measurement between the power wires. To perform the measurement, connect the terminals of the meter under the power wires. Record the result in the installation protocol. Then compare the measured value with the table, which can be found in the installation instructions of the product. Resistance values are also located on the label stuck to the product. If the values match, it means that the product is operational and we can start the heating system.
Many manufacturers of floor heating mats and cables require that measurements be taken three times during installation. After removing the mat from the box, after laying the mat on the floor and before taping, and a third time after tiling and before connecting the thermostat. The results of all three tests should be entered into the installation protocol.