On 29/12/2017 13:00, Huge wrote:

Can you get RCBOs that are a straight swap for MCBs? We have a Legrand
CU that was installed in the late 1990s.




Yes FSVO, we used NOS MK 6936S which are a straight swap in our older MK
CU.

https://uk.rs-online.com/web/p/resid...rcbos/4253719/

The jury is out on whether the current MK 7936S RCBOs are are straight
swap or not.

https://uk.rs-online.com/web/p/resid...rcbos/7116001/


I believe they are the same same electrically but they are different
mechanically.
Some people have said they can be made to fit, others have said they
will not.