some pictures of my voltage, polarity & surge protector (its saved me from open ground & improperly wired pedestals twice)....of course i didn't install this until i had damaged my converter charger when i plugged into a bad outlet.
I used a Progressive Industries ems_lchw50 (50a Hardwire) mounted in the electrical bay -
I also added (although somewhat temporary) a 12v monitoring point.
I picked up some cheap ($10 inductive) panel meters from ebay - they work very well measuring the incoming voltage and current (amp) load on each of my 50a legs.
I also added a 12v outlet (haven't found a good 12v panel meter) - i pulled in a cheap little voltage meter so i can see the charge condition of my house batteries (or the output of the converter/charger)....seems to work well.
Moderator edit to re-size pictures to forum limit of 640px maximum width.
Don R.
'04 42' Haulmark Motor Coach - 450hp/1650tq / 12 spd SmartShift
'12 Jeep Wrangler Sport (manual trans)
'17 Platinum F350 (6.7L, SRW, CC, Long bed, 4x4)