Contrary to common belief, with Thermonet Underfloor Heating a separate mat is not required to be installed in the shower area. The same mat that is installed in the bathroom can run into the shower space without any issues at all providing you have a tiled shower floor and not a shower base.
The cable has an IP (Ingress Protection) rating of IP68 and a continuous earth braid the full length of the cable. This ensures it is safe should the cable come in contact with water and gives you the assurance of safety in the unlikely event of install damage. For further protection we recommend that you do not end the heating system in the shower area.
There are other heating systems on the market that do require a separate heating mat in the shower area. This is due to the fact that the IP rating on these underfloor heating systems is not high enough to be safe to use in the shower area. Often, a separate conduit will need to be run up the wall in the shower and the cold tail extended to allow the mat to be connected to the thermostat. This means that the waterproof membrane in the shower will need to be broken and this does not comply with electrical standards. Having one mat that can be installed in the bathroom and shower is certainly easier and safer for all parties.