This Technical Handbook for Electricity Distribution fixes requirements for protection against transient and permanent overvoltages
The Spanish Electric Company Iberdrola has recently published its own Electricity Distribution Manual regulating the technical characteristics that new installations connected to its network have to comply to, in order to guarantee the quality of such installations.
According to this document, a Surge Protective Device (SPD) can be installed as close as possible to the all-pole circuit breaker. This SPD should be type 1 and able to withstand at least 25kA (10/350μs wave) impulse current per pole. This SPD is obligatory if there is an external lightning protection system on the structure or 50m around.
Besides, the document considers the installation of protection against transient and permanent overvoltages at each electrical panel. Protection against temporary (permanent) overvoltages is optional and it is recommended to be resettable.
Download here the solution of Aplicaciones Tecnológicas, S.A. for type 1 protection at the main board and our device provided with type 2 transient + resettable permanent protection for each electrical panel