10 kA distribution arresters: The adequate choice for medium voltage networks

10 kA metal oxide arresters are widely used in medium voltage network to reduce the number of outages and transformer´s damages due to lightning surges. Studies show that 5 kA arresters are fit for most cases of application in these networks, although they are rarely used, being passed over by 10 kA ones. This is justified by the arguments that the costs differences and logistic questions make it more convenient. The purpose of the paper is presenting some technical characteristics, besides the costs, that recommend more careful studies to select arresters, indicating characteristics for the choice of the more adequate equipment is to a considered network.