Various international standards have specified the requirements and applications of low voltage protection devices. This paper aims to study those requirements and application guidelines for the purpose of designing and constructing suitable protective equipment of Class A category. In this case, Surge Protector Category A is focussed because the service entrance Surge Protection Device (SPD) provides the first line of defence against electrical transients for a facility by diverting high energy, outside surges to ground and it also lowers the energy to a level that can be handled by downstream devices closer to the load. A surge protector is a device that keeps power levels constant against power line fluctuations which cause by lightning mainly and if is not used, fluctuations in the power line can potentially have drastic effects on the equipment such as computer. Therefore the proper coordination of surge protective device specified for Class A category is required to avoid damaging SPDs installed on distribution panels or locally at vulnerable equipment. Class A protection is a protection between the outlets and the long branch circuits and equipment.
