OK, so my son had a little Christmas light up snowman- and the frame ferrous iron (allows magnets to attach) The wiring is 50 incandescent Christmas lights on three strand polarized 110v plug... And he had some of those 'magic rocks' (hematite or more likely hematine) ... And when I went in to check on it all of the light bulbs had blown black and the fuse in the plug was still 'good' (not tripped) and the house wiring did not trip. On the wire before the first lights (between the wall outlet and the first lights) on the frame were these cussed magnets... No burn holes in the wiring casing, no melting as I expected and the wires are still testing good... Now every light bulb must be replaced with an exact equivalent bulb - but how did this happen. A standard short at that point even on three wire should have closed the circuit before light bulbs then tripped the fuse- this is not what happened. Suggestions?