Cables from halogen-free materials with adjusted fire-safety properties

The present state of development of halogen-free power cables exhibiting improved fire characteristics, as is under way in Europe and in Czechoslovakia, is briefly dealt with, and requirements put on such cables are given. Methods for cable testing are mostly taken over from IEC international recommendations. The cables which have been so far developed in Czechoslovakia include low-voltage and signal cables with retarded fire propagation and reduced smoke evolution, whose combustion is associated with the release of virtually noncorrosive products. These cables comply with the IEC 332-3 regulation, Category A or AF. Under development are cables possessing these properties for nominal voltage of 6 kV and cables that will perform during fire for 30 minutes. (Z.M.)