We have experienced a lot of blackouts and brownouts where voltage was once measured at 135V (nominal 240V). Computers and tablets were working and plugged in before we had a blackout and dead after the power came back on.

It happened on different occasions. I need to claim damage from insurance but the assessor cannot pick up any burn marks that proves damage, but all units are dead. how can I prove to my insurance that damage was due to blackout or brownout? Please help with some advice.

  • 1
    \$\begingroup\$ the assessor is looking for signs of surges, not signs of undercurrent leading to failure, yet I have trouble believing that the systems are actually physically damaged by said undercurrent. They won't turn back on until current returns to normal levels though. BTW, I'm in the US, where standard voltage is 120v. what it is where you operate? if for some reason I'm only getting 89v, most of my digital electronics won't power up, but analog stuff still works, but dimmer/slower. \$\endgroup\$
    – Frank Thomas
    Commented Jan 16, 2014 at 14:59
  • \$\begingroup\$ Our normal voltage is between 220V and 240V here in SA. The units have been assessed and all the units are dead. All I could gather is that the boards are blown, but no burn marks. they were working fine and were charging, then there was a blackout. When the electricity came back on they were just dead, nothing. \$\endgroup\$
    – Alzana
    Commented Jan 16, 2014 at 16:46
  • \$\begingroup\$ How do you look for signs of undercurrent? \$\endgroup\$
    – Alzana
    Commented Jan 16, 2014 at 17:18
  • \$\begingroup\$ I have no idea why undercurrent would have damaged your equipment at all. sorry. \$\endgroup\$
    – Frank Thomas
    Commented Jan 16, 2014 at 17:19
  • \$\begingroup\$ While this does not answer the question, here is how to save you some headaches in the future. Get a UPS (Uniterruptable power source) basically a big battery, many different firms like APC and others make them. What it does is when the voltage is too high or low it runs off of battery until the voltage levels are safe again. Of course, there are different size batteries based on model number 1000VA is only 2/3 of a 1500VA backup. When the battery is dead it just shuts off, but your replaced equipment will be safe from future damage. \$\endgroup\$
    – cybernard
    Commented Jan 17, 2014 at 1:56

1 Answer 1


First: Under-current shouldn't actually damage properly designed equipment -- most power regulators have under-voltage lock-out features. Is it possible that inductive transients have over-volted the equipment as part of the off- or recovery events?

Second: You will have to open up the equipment and start trouble-shooting. This may mean going into enclosed power supplies; if you are not experienced with mains electrical work, this would be dangerous! Once you troubleshoot the equipment, you should be able to trace the problem to some particular component -- there should be voltage, but isn't. That shows that such component is broken, and with luck you'll be able to see it physically (but not all breakage leaves physical marks -- some breakage just has to be measured.)

Also: Make sure it's not something simple like a blow fuse or circuit breaker :-)

  • \$\begingroup\$ As @Jon Watte says but also Some times the circuit breakers open at the brownout, but more often when the power is tuned on. \$\endgroup\$
    – Spoon
    Commented Jan 17, 2014 at 13:20

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