This clause of part 1 is replaced by:This standard deals with the safety of fixed immersion heaters for household and similar purposes intended for installation in a water tank for heating water to a temperature below its boiling-point. The rated voltage is not more than 250 V for single-phase immersion heaters and 480 V for other immersion heaters.NOTES1 The water tank may have alternative means for heating water such as the circulation of hot water supplied from a separate boiler.2 Immersion heaters having a rated power input up to 25 kW for incorporation as an alternative heating source in central heating boilers are also within the scope of this standard.Appliances not intended for normal household use but which nevertheless may be a source of danger to the public, such as appliances intended to be used by laymen in shops, in light industry and on farms, are within the scope of this standard.So far as is practicable, this standard deals with the common hazards presented by appliances which are encountered by all persons in and around the home.This standard does not in general take into account:û the use of appliances by young children or infirm persons without supervision;û playing with the appliance by young childrenNOTES3 Attention is drawn to the fact thatû for appliances intended to be used in vehicles or on board ships or aircraft, additional requirements may be necessary;û for appliances intended to be used in tropical countries special requirements may be necessary;û in many countries additional requirements are specified by the national health authorities, the national authorities responsible for the protection of labour, the national water supply authorities and similar authorities.4 This standard does not apply to- appliances intended exclusively for industrial purposes,û appliances intended to be used in locations where special conditions prevail, such as the presence of a corrosive or explosive atmosphere (dust, vapour or gas);û aquarium heaters (IEC 335-2-55);û portable immersion heaters (IEC 335-2-74):û engine preheaters such as those for cars and buses;û heating elements incorporated in appliances such as appliances for heating liquids (IEC 335-2-15); storage water heaters (IEC 335-2-21); instantaneous water heaters (IEC 335-2-35).