Why SPD
Lightning nearby and switching surges damage electronics. Per IEC 60364-4-44, SPD is mandatory where the risk assessment requires it; for rural houses with overhead lines it is always recommended.
Type 1
For buildings with external LPS (lightning rod) — at the input. Discharges the lightning current.
Type 2
In every main panel: protects against switching surges. Required in TN systems per IEC 61643.
Type 3
Near sensitive devices: TV, server, Hi-Fi. Short connection cables — less than 0.5 m.
Wiring rules
SPD is installed in parallel, the connection is as short as possible, the PE conductor is the shortest. The grounding of the object must be working — check ≤4 Ω.
How GorkyCAD helps
The program places SPD in the SLD, checks the protection level against the building category and includes the SPD in the BOM.