SPD (Surge Protection Device)

An SPD diverts lightning-induced and switching voltage surges safely to earth before they damage the inverter or panels. Solar installations use DC-rated SPDs in the DCDB and AC SPDs in the ACDB.

SPDs are sacrificial — indicator windows show when a cartridge is spent and needs replacement, which is a standard AMC checklist item. Effective surge protection depends on proper earthing.

Part of the HUM Solar Glossary — 75+ plain-language definitions for India’s solar ecosystem, maintained as a neutral reference. Browse all terms →