Wylex and crabtree are essentially doing the same thing as I think you need,  both with Siemens designed guts in a single width unit.  Wylex compact DP RCBO for DIN rail  or   Crabtree Starbreaker compact RCBO  The Wylex ones are not a comfortable fit in the previous generation of boards without the use of a file, so spec the 'L' series of boards but I have used quite a few now, and they do exactly as you might hope.

I am told the Crabtree ones are also easy to use though had not yet had need to specify personally. Yet.

PS but too late for a quick edit.

  a link   where folk have spotted that these new RCBOs that are type A have the internal electronics in wired L-N, unsurprisingly.

So for anyone in the habit of installing MCBs onto a live board (wot me ? never.. no),  when fitting these RCBOs should wire in the neutral side first, as if not the flying blue tail will become semi-live as soon as the input is on the bus-bar. 

As I know you are posting from a rather less EAWR  and H & S dominated part of the planet than here in  the UK, and such practices as live working may be more common, I thought I ought to mention it, may save someone from getting a shock.

Or if you're not limited to the UK traditional single pole bus-bar Garo's offering might suit - https://www.meteorelectrical.com/distribution-control/consumer-units-accessories-1/rcd-s-rcbo-s-mcb-s-rcd-s/garo-1-mod-rcbo-s-type-b.html

 - Andy.

I love the Wylex DP RCBOs. Makes testing and fault-finding so much simpler.

You cannot use the Wylex DP RCBOs in three phase boards, they do not have phase barriers. 


I phoned and checked. 


Andy Betteridge