Your are going to not only run yourself ragged but, confuse yourself at the same time?
There are many reasons you would not come off the RCD protected side or unprotected side of a conumer unit, due to the RCD type allready installed, MCB suitability and whether you can match one to the board etc etc.
Most installers I know and that includes myself, typically stay away from the main house consumer unit and install a dedicated CU for the charger. The reg’s don’t say you can’t come off the main house CU but, you can run into inherent problems doing so. It is therfore preferable and a better job done overall better to install a dedicated CU for the charger and keep things seperate. You will find your Ohme installer will also adopt this method.
You will find this video runs over somemore of the issues faced connecting the charger to the main house CU. (Notice its a new home and same Zappi charger)
“The guy in the video you posted also wrongly assumed, that the black label on the side of the cut-out fuse denoted a 100A fuse is fitted. The black label denotes the the actual carrier rating, in a similar way a 13A plug is only rated at 13A but might have a 5A fuse inside. If cut-out carrier didn’t have the label on front stating the size he wouldn’t know and must assume its 60A fitted!”
Sec 722 of the regs, requires a RCD protects an EV charger and shall discount all live conductors, both live and neutral.
Most charger’s today including Ohme, come with whats known as a Residual Direct Current Detecting Device (RDC-DD). This is often built within the charger PCB, rather than an actual physical device. Its purpose is to monitor and disconnect if any DC issues arise on the AC side, which could interfer with the operation of the RCD.
If the charger does not have any form of RDC-DD a Type B RCD would be installed to supply the charger upstream of the charger. If the charger has RDC-DD protection a main switch can be used – However many I know inc myself will install a Type A RCD upstream of the charger, they only cost a few quid and add an additional elemant of safety, so its daft not to, however this might be pushing it for Motability installers, given MO would have wanted a charger plus installation for pittance!
Type A and B RCD’s won’t affect DC up up to 6mA and are the most used in domestic installations.
Surge Protection devices (SPD) are an important factor in amendant 2 of the regs and will go into them in another post, as I’m not sure if installers are automatically opting MO customers out without asking!
Hope this helps 🙂