High Headroom or How to Prevent Premature SPD Death

Low headroom can be uncomfortable in a vehicle, but in a surge protection device (SPD), it can result in the destruction of the protector. Knowing where to set headroom in terms of a protector's turn-on point is the first step in protecting one's investment. The specified clamping voltage of SPDs should be as close to the value of the AC input power as possible.