The heating cable is applied inside the pipe in direct contact with the medium.
An easy way to frost protect existing and already insulated pipes and at new applications is to apply heating cables inside the pipes.
The advantage with this method is that the cable will get in direct contact with the medium that is to be heated, which gives a fast melting and less working expenses, as more difficult conditions are solved with a lower output.
A heating cable with higher output than 12 W/m should not be applied in direct contact with a plastic pipe as the cables sheath temperature might damage the pipe.
At a higher required power the heating cable can be applied in sand with a distance of some centimetres in order to produce a heat barrier between the cable and the pipe.