Went to price up some bathroom work where the room had been gutted. Going up the centre of the wall (previously tiled) was some capping with a rawlplug right through the middle, behind the capping was 1 x 2.5 and 2 x 1.5 so it must have been a tight fit getting them all in there in the first place. Somehow the drill bit managed to find a way through just nicking the outer insulation of all 3.