If you assume magic is a "third force", it may well share an induction/propagation relationship with either or both magnetism and electricity, in much the same way that those two do -- so there may well be electromagical and magnetomagical waves generated by magical effects (much in the same way that calculators generate radio waves you can hear on an AM receiver), and these are what muck up electronics.
Or like Chris said, magic causes EMPs.
-- Bob
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For Jor-El so loved the Earth, he sent his only begotten son...
Or like Chris said, magic causes EMPs.
-- Bob
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For Jor-El so loved the Earth, he sent his only begotten son...