How do you design a coordinated surge protection system for a facility?

Coordinated surge protection uses cascaded SPDs at multiple levels: Type 1 at service entrance (high surge current capacity, 200kA+), Type 2 at distribution panels (50-100kA), and Type 3 at point of use for sensitive equipment. Coordination requires adequate impedance (typically 10m cable) between stages for let-through voltage limiting. Select SPDs with appropriate voltage protection rating (VPR) for equipment immunity levels. Consider separate SPDs for data/communication lines. Document installation requirements and specify replacement criteria based on surge exposure.