Perhaps a rather rudimentary question but what is “full mode” protection? I assume that it is a combination of common and differential modes but it seems to me that it is generally common mode that is provided.
An SPD configuration based on connection type 2 (CT2) is required on a TT earth arrangement if the SPD is upstream of the RCD. The RCD being downstream of the SPD would not operate should the SPD become defective.
An SPD configuration based on connection type 2 (CT2) is required on a TT earth arrangement if the SPD is upstream of the RCD. The RCD being downstream of the SPD would not operate should the SPD become defective.