I had some central AC installed in my attic recently, and a short circuit (or some event) occurred when one of the two 240V circuits were switched on. The circuit breaker did not trip; the installer had to manually switch the circuit off to stop the event. The lightbulbs dimmed in the house, my cable TV was fried, and I noticed what turned out to be a leak in my main water pipe under the foundation.
I have a boiler system for heating, and I'm thinking the short circuit leaked current across my boiler pipes and arced over to the water line and poked a hole in it.
I've been told that this is possible, but I'd like to know for sure.
It sounds to me like you have some grounding issues. Perhaps grounding rods and ther water pipe ground are not bonded together, or no grounding rods at all (older service). The cable blew due to the current flowing through the pipe going to the cable bonding nut and through the cable box (and back down the ground wire probabally).
I would say you have at least 2 problems:
1) High resistance gound (does not allow enough current to flow to trip the breaker.
2) Bonding problems. All grounds are supposed to be bonded together to create an equal potential. Improperly bonded grounds will easily destroy electronic equipment (cable sattilite system, computer networks etc) as they use and link grouns on different points in the electirical system.
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