John:
FWIW, you not doing anything further until you have the electrical permit 'in-your-hand' would be my first advice. You've been around here long enough to know the pitfalls of getting 'caught'.
Regarding the situation with 'your' customer; I had a similar disaster once. Long standing relationship with prop owner and mgt co of a lot of nice props. Had a 'triple net' bldg that the prop rep neglected to 'check-in on for over 18 months. An issue with HVAC arose, and I sent one of my men to check the power end. Turns out that the 3 phase power source was from a 1 phase panel. Idiot used the Neutral bar for 'c' phase, so....hot always, and no OCP except the feeder main.
Went to correct the mess; permit in hand the next day. Got a $$$$$ fine from the local bldg dept for 'previous unpermitted/uninspected work! The city had no clue who did what, so the guy doing it the right way gets a blast btwn the eyes. All turned out well after finding the right person to talk with. The 'tenant' fessed up and I had a man to man with the hack afterwards. 'My customer' wound up booting out the tenant for a lot of serious issues, and the prop rep went to the unemployement line.
Stay safe
