This is a true story that happened about 30 years ago.
Our boy scout troop was in a cabin in Blue Ridge mountains.
A few of us were hiking down the road. There were a few large
manholes on the side of the road.

We opened one. It was about 3 ft deep. As near as I can remember it
had only one cable inside. The cable was flexible and had a tee in
the middle with a removable rubber cap.

One of the guys thought it was a water valve. He stuck his thumb into
the "valve" thinking he was going to wet the rest of us and a blue
flame shot out. It cooked his thumb nail.

If I remember the details, it was only one conductor. The tee must
have been there to be able to plug in another line in the future. It
was almost like it was a quick connect plug.

Of course, we never told the scoutmaster. Anyone have more info on
what exactly we were messing with?