On Sat, 13 Jun 2009 16:48:34 +0700, Jeffrey Race wrote:
>Thanks to all for suggestions. AC power line is indeed likeliest
>ingress. I checked and there are no overvoltage clamps on the
>200 m power feed from the pole; we are at the end of the line.
>
>Grounding is excellent at our home (I did it myself, to ground
>rods and building's rebars) but I never got to put in the big varistor
>to clamp the feed; its a GE/Harris V275HE250 device rated at
>20,000 amperes. We'll do it next week and It will sacrifice itself
>during the next hit and blow the breakers. We'll also get after
> the state electricity monopoly to install spark-gap protectors or
>something. (Expected reply "If you're not happy with your
>service we can disconnect it for you.)
>
>Among other items damaged was the APC uninterruptible
>power supply. APC replaced it for us.
Jeffrey, while it may not apply to you, you may want to check out
"StrikeStop" - a surge protector device that fits between the service
entrance and the electric meter. This URL happens to be for my local
power company, but I suspect the product is available from most
utilities.
>http://www.duke-energy.com/energystore/strikestop-residential.asp
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