"John Rumm" wrote in message
...

A standard masonry drill will do for most cases. If there is loads of
rebar reinforcement in there, then you could try one of the specialist
rebar drill bits, or one of the Bosch multimaterial drill bits (these will
drill concrete and metal without being damaged - note that you don't want
hammer action on the metal though)

It can be quite dangerous drilling rebar.
Some panels are pre-stressed and odd things happen if you fracture the
rebar.
Ever seen concrete explode before?