Late 70s or early 80s horror movie about high school class reunion where a couple having sex get electrocuted and fried

I rented this in the late 80s and have been wondering what the title is. It MIGHT be Slaughter High, but I don't know.

It's a high school class reunion. In one scene, a couple is having sex in a bed. The killer electrocutes the couple as they have sex, ending with them being totally fried, all burnt up. Lots of smoke.