Principles of positioning and wiring of surge protections and lightning current arresters
Surge protections and lightning current arresters cannot be installed in the distributor at random. You must be aware of the fact that protection should be placed in closest proximity to the input feed cable in the distributor in order to minimize the inductive loop area
Another important condition for the wiring of protections is to minimize the impedance of interconnecting conductors. Since the fault current flowing through the protection has a frequency at which the current does not flow through the whole cross section but pushes towards the conductor surface (skin effect), it is necessary to use a stranded conductor or a strip conductor for the wiring of protections. Furthermore, the length of the interconnecting conductors must be as short as possible (the total length of interconnecting conductors must not exceed 0.5 m). The cross section of the interconnecting conductors should be as large as possible - maximum up to the cross section according to the terminal type.
The cross section of interconnecting conductors is recommended to be larger by at least one sequence number than the PEN (PE) conductor diameter (e.g. if the PEN conductor diameter is 10 mm2, the cross section of the interconnecting conductor should be 16 mm2).
If protections are placed in a circuit fitted with residual current devices (RCD), the protection must be set before the RCD (not in the RCD circuit) to avoid
spontaneous RCD availability due to surge protections or lightning current arresters.
If the RC is placed before the protection, it is necessary to use the delayed RCD type, e.g. S-type or G-type.