Аннотация
The mechanism and conditions of the beginnings of breakdown in insulators included the clusters of the point defects was determined using the model of the charged sphere invested into homogeneous electric field. The dependence of the critical field Екр was obtained, when on the clusters of the point defects (CPD) micro plasmas arise. From this dependence follow that Екр proportional to radius of CPD and the density of the ionized impurity in them.