EN 50525-3-31 applies to non-sheathed single core cables insulated with halogen-free thermoplastic compound and having low emission of smoke and corrosive gases when exposed to fire.NOTE 1 Low emission of smoke is checked in accordance with EN 61034-2. Low emission of corrosive gases is checked as part of the check for absence of halogens (see Annex B of EN 50525-1).The cables are of rated voltages U0/U up to and including 450/750 V.NOTE 2 Cables rated 450/750 V may be used at 600/1 000 V when this cable is used in fixed installations with mechanical protection, within switchgear and control gear - see HD 516.For cables rated at 450/750 V there are two types, Type 1 and Type 2. Type 2 cables are required to meet a more severe test for resistance to flame propagation (EN 60332-3-24) than Type 1, and have particular suitability for installation in bunches (see also HD 516).The cables are intended for fixed wiring applications.The maximum conductor operating temperature for each of the cables in this standard is 70 °C.NOTE 3 HD 516 contains extensive guidance on the safe use of cables in this standard.This EN 50525-3-31 should be read in conjunction with EN 50525-1, which specifies general requirements.