A neighbour arrived at my door as the local knowledgeable about electrics clutching his some 4 month's old mitre saw. "Trips the rcd everytime I try it".
Down to my workshop where of course it performed perfectly OK - consistently! Get a new RCD!
However I was surpised at the amount of sparking at the brushes until I learnt he'd got it on offer from B n' Q. Ahhh - cheap brushes then.
But what did puzzle me was that when I released the ON switch, sparks continued from the brushes/commutator - why? Rob