Here was my protocol when I performed extensive chassis and structural mods to my coach.
I disconnected all battery leads.
I then pulled all fuses and switched breakers to off.
I unplugged all electronic devices including the auto level jack leads and plugs, anything electrical was unplugged.
As mentioned before, ground lead was as close to work as possible and assured of good contact.
I had spent months adding a frame extension for torsion axles, a very sturdy 2x8Ē steel bumper, a genny tray, and support for other equipment.
Upon reconnecting all electrics I had no gremlins to overcome. All work was performed in 2018 without any consequential damage.