I came across this first timer yesterday and was wondering about its setup. The main disconnect (P1) is in it’s own box, making the others “subs”. The older sub (P2) is the original two-wire box and the newer one (P3) handles all the newer three-wire circuits. In P2 there is a 220 circuit in the lower right corner with the ground wire attached to the neutral buss, is this kosher? Don’t the neutrals and grounds need to be isolated in P3? There are plenty of other issues that an electrician will be called in so I’m covered, but I would like to explain it in my report in an intelligent way that covers the bases. Many thanks in advance from a long time fan.