Is this Main Panel Safe?
First off, I am a lifetime DIYer, but am not formally trained in much except teaching high school math. I can usually figure things out, but I do not mess around with electricity. Saying that, I am trying to avoid having to call a licensed electrician unless I know I have a problem.
We are in the midst of planning a series of renovations to our house, so I'm in the planning and demoliton phase. Funny how you tear into something, and it will lead you to bigger problems.
The one room I am focused on right now (all drywall gone) had 12awg old 2 wire without ground. Pulled all of the old stuff and wired up with NM 14awg (outlets only for the moment). This got me into the main panel so I could complete the run. Found this (see picture).
Bottom of panel is rusty. A number of the neutral/ground bus bar screws are rusty. Upon closer inspection, I found a few of the breaker's hot lugs/screws were also rusty.
Undaunted, I wanted to make sure I was tying into the right breaker. Put tester on breaker's hot post and on the box. Nothing. Moved tester to the neutral bus bar, and I get 125V.
1. Should I be concerned/alarmed that the main breaker box is not grounded? I think so.
2. System is grounded to cold water pipe. I want to ground it to...well...the ground. Reason? Moving to PEX so metal water pipes will be going away. Suggestions please on proper ground rod and bonding technique (awg suggestion also appreciated). Under house? Away from house?
3. Since the box has rust in the bottom (still solid metal under rust) and on some breaker's hot posts and neutral bus bar screws, is this thing safe?
Specs: ITE 200A Main Breaker. UL-Listed, but no date. Model G4040MG1200
Service: 4/0 AL (2 hot/1 neutral) from Meter.
Ground: to a cold water pipe (going to change that).
Would more pictures be helpful?
FWIW, there is a 30amp breaker from Main feeding a subpanel upstairs. PO did this when they turned attic into living space. Aside from a bathroom fan/heater/light, it's mostly all lights and outlets.
There is also a 60 amp breaker from Main feeding a subpanel just next to this Main Breaker. Same PO.
Lastly, there once WAS an above ground pool (same PO) fed by a 100 amp breaker on the main. This breaker is taped OFF, but I would like to move this to the garage for another subpanel, but I'll leave that for another post.