We are working on a project where the main LV panel had two incomers, one from a transformer and one from a generator. The supplies are interlocked so only one will be used at a time (not in parallel operation).
The LV switchgear manufacturer advised that they would install the SPD on the load side in order to cover both supplies (if they installed it prior to the incomer of the TX then we wouldnt have surge protection when the generator would be operating).
Can anyone confirm if this is correct? Or maybe I need two SPDs (one for each incomer)?
I am not sure whether connecting the SPD on the load side would be protecting the system.