This is a Wylex REC main switch. 

They are both labelled as an AC22A, but the one with the the SPD is a WS102 which is a consumer unit main switch with a slot to accommodate a balcony busbar allowing it to to secured under output terminals screw heads, whereas the isolator in my photo is the “real” REC switch a WS102-TT with double screw terminals that tighten plates down onto the conductor rather than being a cage clamp terminal.


I presume the TT in the code refers to it being double pole and suitable for a TT earthed installation. If you pay particular attention you will note the main switch with the SPD is marked as a single pole isolator, despite being double pole, whereas the isolator I have posted a picture of is labelled as a double pole isolator. Though in both photos the switch is down, so that’s not obvious unless you look carefully.


I presume the SPD unit has been supplied with a consumer unit main switch rather than a REC isolator on purpose.


I would expect to see two short pig tail conductors with fork crimps on both ends allowing them to be secured in the balcony busbar slots under the terminal screw heads on the output, the bottom of the switch with the incoming supply connected feeding into the top terminals.


What I cannot see is how they the main switch can be connected to the SPD using busbar.


Andy Betteridge 

Single pole isolator double pole consumer unit switch with balcony busbar slot.

The double pole REC isolator without the balcony busbar slot.

Same with Hager.

https://electricalcontractingnews.com/news/hagers-ask-the-expert-understanding-surge-protection/

Because the Hager main switch has slots that allow fork crimps to be secured under the output terminal screw heads.

Like this RCD.

Very interesting Andy, all I can guess is that Wylex has updated the design of the rec2 and rec2spd and there are several version of both of them out there! The earlier version with busbar links and the newer with flexible links...I remember fitting a rec2 isolator a while back that had a single screw on each of the connections as opposed to 2 like in your photo! I've also just fitted a rec4 with two Allen screws per terminal (like the newer Henley blocks and cutouts) and instead of a red operating leaver it was brown with a blue section above the neutral. I guess manufacturers are constantly refining and changing their designs without any notice!

I installed a Wylex consumer unit with a preinstalled SPD several weeks ago, but didn’t take any photos.


As I remember it there is conductors linked between the balcony busbar terminals of the CU main switch and the SPD terminals.


It seems impossible to connect them with busbars unless the manufacturer supplies some bent busbars that I have not seen.


What is on the other end of the SPD conductors in the in the main switch SPD combi unit you have been supplied with?

Have you considered that the SPD conductors in the photo are the wrong way around if they have a ferrule on the other end or just the bare conductor?


The fork crimps in the balcony slots on the main switch outputs and the ferrules or bare conductors in the cage clamps of the SPD.


If you watch German YouTube videos of SPD installation you will see they put bare conductors into cage clamps as they are not damaged by the screws, whereas they use ferrules in screw terminals to avoid the screws damaging the conductors.