When sourcing isolators, the price is primarily driven by voltage ratings (kV) and current capacity (A). High-voltage disconnectors (e.g., 110kV to 550kV) require advanced ceramic or composite silicone insulation and robust mechanical structures, significantly increasing costs. You must verify the Short-Time Withstand Current (STWC) and Peak Withstand Current to ensure the device can handle fault conditions without failure. Additionally, the mechanical endurance class (M1 or M2) affects the price, as higher cycle ratings require more durable linkage systems.