Thunder hammers are pretty kick ass against most monsters as long as you're careful about angles. I'm pretty sure you can calculate the path it's going to take. For example if you are "@" and the monster is "F" and the walls are "#"
You don't want to hit the monster because the bolt will bounce off of the corner of the walls right back at you. But in this scenario:
You're safe because it'll take a 90 degree angle off the wall.
I'm not entirely sure about that but it does seem to be somewhat predictable.
And anyways if you have sufficient electricity damage it probably won't hurt you (though it may still break your equipment)