A major pre-existing document of relevance is BS 7671 (IET Wiring Regulations). It specifies reaction to fire characteristics for cables in a number of places, most but not all of which are for installations in buildings and construction works and therefore fall under CPR.

The existing requirements of BS 7671 can be used to illustrate the most important determinant for cables and reaction to fire under CPR – namely the classification.

The classification splits cables into 7 classes in respect of their reaction to fire. They range from Class Aca, being essentially non-combustible, as for instance bare MICC, through to class Fca, which is for cables having no measurable resistance to the spread of flames.

From 1st July 2017, it will be compulsory for cables, with a reaction to fire performance and that are intended for permanent installation in buildings and construction works, to be accompanied by a Declaration of Performance (DoP) and have CE marking.