Quote:
Originally Posted by brainz01
I'm not sure what else to do for the low voltage stuff - - it was already on surge protectors and UPS.
|
Low voltage electronics, powered from AC mains, must withstand 600 volts without damage. That standard existed long before PCs existed. Today, most low voltage electronics are more robust.
UPS does not even claim protection equal or superior to what is already inside electronics. Again, read spec numbers. How many joules does it claim to absorb?
Plug-in protectors can even compromise superior protection inside appliances. Your example apparently demonstrates that.
Sometimes homeowners fail to grasp what does protection. The world's best protector in a main or sub panel can do nothing if a critically important device is not properly installed - earth ground. Sub panels must not even have an earth ground. So a protector there may be just as ineffective as a UPS or plug-in protector.
A glaring human mistake is apparent. Assumed: a protector does protection. No protector does. Effective protectors made a low impedance (ie less than 10 foot) connection to single point earth ground. Earth ground does protection. If that ground does not exist, a protector can even make appliance damage easier.
Wall receptacle safety ground obviously is not earth ground.
When damage happens, an investigation (to find that human mistake) starts with earth ground. We did this often.
For example, in one venue. The entire network of powered off computers were damaged. We traced each surge path by literally replacing every damaged integrated circuit. All hardware fully restored. (How many others can do that?) Some ICs even had the plastic case shattered on its ground pin.
They foolishly used plug-in protectors. All computers were powered off. Those plug-in protectors connected a surge incoming into computer motherboards (bypassing robust protection in its power supply). Outgoing via NICs. Then into other computers that had connections to a phone line and that 'telco installed for free' protection. Outgoing from those computers via a modem. And yes, we even restored all modems.
Damage because a 'whole house' protector did not connect that surge to earth BEFORE entering the house.
So, you had damage? From that post, your protectors do not make a low impedance connection to single point earth ground (all four words have electrical significance).
Induced surges are another urban myth exposed by so many EE facts - with numbers. Or demonstrate by example. (If not yet obvious, I have been doing this stuff for many generations.)
Lightning struck a lightning rod. So maybe 20,000 amps were connected to earth on a hardwire that was outside - only four feet away from an IBM PC. That is a maximum induced surge. That PC (and all other electronics) did not even blink. Because induced surges only do damage when wild speculation (that also promoted ESE device) exists.
If lightning does any damage, a human searches for his mistake that made that damage possible. That investigation always starts with the only item that defines a layer of protection - earth ground. Apparently you did not have and probably should still correct a missing or compromised earth ground.
That is your 'secondary' protection layer. Your 'primary' protection layer also should be inspected.