Hi,

Seeking some clarification on Part P. 

Existing 6mm cable protected by a 25A RCBO in main CU. Is an upgrade to a 40A RCBO, notifiable under Part P? It isn’t a new circuit, only a modification which after modification, complies with BS7671. Thoughts? 

The current 6mm cable is sized down to a 4mm cable in a junction box and then goes off to feed 2 socket radials.

Would adding 2x OCPD (for example 16A MCBs) at this junction point, be seen as a “new circuit” or would this also be a modification? At present, these OCPD don’t exist, so would need adding from a new DB. 

I am no longer Part P registered to self notify, and albeit I want to do this myself, I also want to do it properly so if I need to outsource any of this I can (but would much rather not!). 

Thanks.