I used to work for a company that liked to have their panels painted.
It caused us a lot of problems - Try to keep them from painting the Screw Slots and Hinges, or you'll have fun even opening the doors & covers.
Sometimes the paint they use doesn't adhere too well to the factory finish.
(Unless, of course, they use sandpaper or steel wool - please don't)
Electrical stuff is beautiful just the way it is.
I take a good pride in my work. The services and panels should stand out for what they are. When the painter tells me the HO wants them painted magenta, like the rest of the room, I can really pee somebody off
I paint them alot..I like to lay them out and paint them before I install them get a better job..I have painted them when I am done..I paint them so they don't use latex on them and the paint peals off..I use rustolem or other types of metal paint..I have even gutted them taken them to body shop had them painted and reassembled them and installed them..So if there is a code forbiding them to be painted..oops..:grin: my painting is an intentional act..
FWIW, the OP asked about painting the exterior of a panel, not an "exterior panel". Funny how quick the subject can go in the wrong direction/intention.
Pierre, neat picture. Wonder if they do Mossy Oak:grin: