Type 1 Surge Protective Devices are typically mounted on the line side of the main service entrance. They protect against external surges caused by lightning or utility capacitor bank switching.
Leviton Type 1 SPDs offer first line defense against external surges. They use the largest MOVs in the industry (40mm & 53mm) and are outdoor rated. Plus, some of Leviton’s Type 1 SPDs feature an audible alarm warning that the device is no longer providing the rated surge protection.