EN 50525-2-21 applies to flexible cables, insulated with crosslinked elastomeric compound, and sheathed with either crosslinked elastomeric compound or thermoplastic polyurethane (TPU). The cables are of rated voltages U0/U up to and including 450/750 V. The cables are intended for a variety of applications where appliances or equipment, including heavy industrial equipment, require a flexible connection to the power supply. The maximum conductor operating temperatures for the cables in this standard are 60 °C (R types), 90 °C (B types) and 110 °C (G types). The following particular cable types are included: -General purpose cables (RR and RN types); -Water-resistant cables (RN8 types); -General purpose cables (BB and BN4 types); -TPU sheathed cables (BQ types); -Heat resistant cables (GG types) NOTE HD 516 contains extensive guidance on the safe use of cables in this standard. This EN 50525-2-21 should be read in conjunction with EN 50525-1, which specifies general requirements.