10-way split consumer unit; is there a preferred siting for the SPD?

Question:

In a 10-way split consumer unit with two RCDs, is there any preferred siting for a type 2 SPD to cover the whole installation?

Answer:

Typically a type 2 SPD installed in a consumer unit will be installed next to the main switch so that it protects all the final circuits within the unit.

Should an SPD be installed on the load side of an RCD, regulation 534.4.7 would need to be taken into consideration.

Some other the regulations to consider include:
Regulation 534.1.1.1 requires type 2 to be installed at or near the origin.
Regulation 534.4.8 requires consideration for the limit of the total wiring of the length of conductors between the connection point of the SPD and the assembly which should preferably not exceed 0.5 m and in no case 1.0 m.
Appendix 16 which gives typical installation methods for SPDs.

Technical expert - NICEIC