A major home improvement company renovated the outside of our home. During the process the subcontractor jacked into our breaker box without permission and without the use of an electrician. After complaining we finally hired an electrician to review the breaker box and discovered the ground wire had been removed from the ground for almost a 12 week period. My question is what potential harm could of come of this event?
If you have not experienced any problems with equipment and have not gotten any shocks, then you dodged a bullet. No harm, no foul, sorta. Just glad you found the problem before anybody got hurt. I'm sure no damage to appliances.
I don't think you were in any immediate danger. Decades ago, houses didn't have grounding like we have today (if any at all), and while there were definitely some incidents, most people managed to live their lives just fine. You'll still find old houses in North America that are not properly grounded, and you can only imagine what third world countries are like.
That being said, it is a safety feature so you were at higher risk of electrocution should a short or fault have occurred.
If no harm came of it and no equipment was damaged, there are no lingering effects of the missing ground assuming it was properly corrected.
I assume you have neighbors that share the same transformer.
I would also assume that they have their main panels properly grounded.
That would mean that your neutral was grounded.
Just not as close as it should have been.
I also assume that your neutral, and ground wires were still connected together in your main panel.
If you loaded up on only one half of your panel, the voltage on your neutral would have not been zero.
The amount voltage would have been considered low-voltage. ( The highest it could go is half of the voltage of one leg. Which would require that you had a short between that leg and neutral, that wasn't through a breaker. )
So that means you could have gotten a shock, but it probably wouldn't have been life-threatening.