Solar DC SPD

In an electrical systems, Solar DC SPDs are usually installed in tap-off configuration (in parallel) between the live conductors and the earth. The operating principle of Solar DC SPD can be similar to that of a circuit breaker.
In normal use (no overvoltage): the Solar DC SPD is similar to an open circuit breaker. When there is an overvoltage: the Solar DC SPD becomes active and discharges the lightning current to earth. It can be likened to the closing of a circuit breaker which would short-circuit the electrical network with the earth via the equipotential earthing system and the exposed conductive parts for a very brief instant, limited to the duration of the overvoltage.
For the user, the operation of the Solar DC SPD is totally transparent as it only lasts a tiny fraction of a second.
When the overvoltage has been discharged, the Solar DC SPD automatically returns to its normal state (circuit breaker open).