I find it odd that the circuit panel is mounted directly over the entrance point of the conduit/cable. It should not be mounted that way, and there should be a drip loop in the cable before entering the panel. I’m not into elec, maybe an electrician will weigh in on this.

As far as the water, do you have high groundwater in your area (basement damp or dry, sump pumps alot or never)? Does it only leak in when it rains?