This International Standard applies to sound signalling devices with integral enclosures or to sound signalling devices intended to be fitted into or supplied with enclosures according to IEC 60670 intended for household and similar purposes with rated voltages not exceeding 250 V a.c. or 250 V d.c. and with rated power inputs not exceeding 100 VA. In these sound signalling devices an indicating light having a rated input power not exceeding 10 VA may also be incorporated.