Using a MULTIMETER follow these two pictorials on what to measure for for both the 50A Service and the 30A Service if you decide to add that as well...
50AMP 220VAC SERVICE
NO SHOCK ZONE Image
30A and 20/15A 120VAC SERVICE
NO SHOCK ZONE Image
I like the typical drawings shown at the beginning by someone here on how the PEDESTAL wiring should look...
Google image
Make sure your electrician is licensed and has Insurance. This will pay for couple of thousand dollars needed to replace a few of your appliances if wired wrong... If you use your father-in-law or good friend then guess who pays...
Roy Ken
