In message <17F4541E55F74F6AACBF9107A0A2A9B7@Pete97219Compaq>, Pete Perkins <[email protected]> writes > In the North American distribution system the short circuit current >that can be expected from the usual 115V domestic & commercial outlet >is on the order of 7000A. ... which is why you don't have the problems with mains harmonic currents that we do in Europe - your typical mains impedance is far lower. Ours is about half an ohm at the point where the utility wiring meets the house wiring. So the prospective short-circuit current is only about 460 A. Even so, ordinary fuses are inadequate (breaking capacity around 100 A - they explode with a real short-circuit), so we use 'enhanced breaking capacity' or 'high breaking capacity' types. -- This is my travelling signature, adding no superfluous mass. John M Woodgate
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