HOLE SAW TECHNIQUE
Determine the position of the outlet on the panel and mark the centre. Now mark 20mm either side of the centre mark.
Drill each hole with a 65mm hole saw.
JIG SAW TECHNIQUE
Determine the position of the outlet on the panel and mark the perimeter of the cut-out. Drill a 10mm hole inside each corner.
Insert jigsaw blade and cut along the lines, leaving the radiused corners intact (this prevents stress in the panel).