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Surge Protection Tools

SPD Calculator

Choose a starting surge protective device type for AC, DC, or PV systems based on exposure, installation point, and system earthing.

Inputs
Result
Type 2 SPD

Use Type 2 protection as the starting point for normal distribution-board surge protection.

Lightning exposureLower exposure
Installation pointMain
SystemTN
Selection modeRule-based type family
Next checks
  • Check Uc against the system voltage and earthing arrangement.
  • Coordinate upstream and downstream SPDs when multiple levels are installed.
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Formula and Method

The calculator uses a rule-based selection matrix: higher lightning exposure points to Type 1+2 protection, downstream distribution points normally start with Type 2, and sensitive equipment may need Type 3 coordination.

Assumptions

  • Low-voltage power system
  • Preliminary product family selection only
  • Final SPD rating must match system voltage, earthing, short-circuit conditions, and installation standard

Important Warnings

  • Do not use this output as proof of IEC 61643 compliance.
  • PV and DC SPDs must be DC-rated and selected against maximum array voltage.

FAQ

Is Type 1+2 always required for overhead supply?

Not always, but overhead supply increases lightning exposure. Use the result as a prompt to check the project risk assessment and local requirements.

Can this calculator choose Uc, Up, In, or Imax?

This first version chooses the SPD type family. Voltage and discharge-current ratings still need project and product datasheet verification.

Next calculators

Continue the selection workflow.