Will I find an arc-welder connected to the other side of those wires?
Seems like what the tenant in my grandmother's house in Colombia was doing to power the arc welders in his shop.
He had banged a couple of nails to the old wooden pattress that held the whole-house disconnect knife switch (this was a house built in 1949 so you can imagine the type of wiring). These were somehow connected to the switch.
Did you need to use an arc welder? Just hook the wires over the appropriate nails in the pattress!