Yes, The surge arrester must be protected upstream by a disconnection circuit breaker.

The surge arrester is not intended to be exposed to a permanent overvoltage (phase/neutral inversion, or neutral rupture).
In this case, it would be short-circuited and may damage the switchboard.

A disconnection circuit breaker protecting the surge arrester against short circuits is therefore required to ensure the safety of the electrical installation.

Released for: Schneider Electric Thailand