1 can cover's how much area? an is it safe to use around electrical conduit an meter base area?

It is important to know this used directly on each nest you find. By the question that was asked (how much coverage does it have), it made me assume you were asking because you thought it was for treating a large area similar to a pesticide used on a whole garden. It does not repel anything. It kills on contact only and pretreating an area has no effect, and if the spot is attractive to them, they can and will move back in once the chemicals dissipate. If you have a spot that keeps getting infested like a electric service panel...put a bag of mothballs in the panel and nothing will want to be around that chemical. Mothballs do evaporate over time however so it will need replacement every few months.

The foam has low conductivity and can be use around electricity. When you put it in an entrance it will block that entrance and keep wasps from coming out that entrance. If there is a second entrance and you don't treat it they will come out there.

The amount of area it covers really varies on how many wasps/hornets you are trying to kill. It usually last a good while though. As far as it being safe to use around electrical conduit, as long as you are using the Commercial product then yes, it is fine to use around electrical boxes, etc.

One acre, it is safe to use outdoor only, conduit near by should be OK. However, it does not attract wasp or hornet from our experience.