It has two parallel bus wires which carry electricity but do not create heat. They are encased
in a semi- conductive polymer, this polymer is loaded with carbon and when an electrical
current is applied will vibrate on a molecular level, generating heat, as these molecules heat up
they will move apart and stop conducting electricity, hence they will self limit themselves, on
cooling back down the molecule will then start to vibrate again.
The benefits of this cable are the ability to cut to length in the field, It is more rugged but not
necessarily more reliable than series or zone heaters, it cannot over-heat itself so in theory it
can be crossed, but it is bad practice to install tape in this way.