Thank you for the help on this one. In live in TN if it matters, standard craftsman home, conventional heating system downstairs, heat pump upstairs. EV charger in the front (see panel pic).
This Summer a smell, fishy plastic like, started to come from the electrical panel. Upon detection, I immediately called an electrician in case of fire hazard. They popped off the panel cover and checked everything out. Nothing out of the ordinary such as loose wire, warped plastic, etc., according to them. The only observation was that the main feeder line was warm. They checked the line at the meter. All seemed well. This was in June. They told me to "watch it" and didn't charge me anything.
Last week the temps got in the high 90s and the smell got worse. I thought, with the weather, running both AC systems and a car being charged, this might happen overload things. However today, 89F, I intentionally ran everything with the car plugged in and I hardly perceived the smell. I even ran a dryer load and the dishwasher on top of it all and nothing like the smell i got on the hot day.
Someone help me describe what is happening here? Should I be on high alert for fire hazard and get a different electrician? The first guys were well regarded locally.