Power Surges & Protection


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Old 06-11-18, 11:10 PM
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Power Surges & Protection

Saturday afternoon and evening, we had some pretty bad storms pass through NJ. When I got home from work about 10pm, I saw the clock on the range blinking, and figured we had lost power. I reset the clock on the range, and went to do the same to the microwave.

I distinctly remember hitting the “CLOCK” button then “1-0-0-3” and the display read “Press 1 – AM, Press 2 – PM”. I then pressed 2.

I turned and took 2 steps away, and heard a clicking noise coming from behind me. I was alone, so I turned around quickly, but didn’t see anything. As I turned to walk away again, I heard a loud POP. I opened up the door of the microwave, and smoke was coming out of the vent.

Being that the microwave is only 2.5yrs old, and cost $450, I said a few choice words I can’t repeat here. Whatever exploded in the MW, it didn’t trip the breaker.

Of course, my wife later wanted to know what could have done that. My guess was a power surge, but I was confused about why it sat there for who knows how long, patiently awaiting someone to set the clock, and as soon as someone did, it decided to kick the bucket. What kind of component inside the MW would sit there and not be used until the clock was set?

That is a question that is only extra-credit. That’s not my main question.

Sunday morning, when I went to turn on the Keurig to make coffee, I found out that that, too, had traversed to the great appliance store in the sky. I checked the GFCI, switched to a different outlet, and nothing. The Keurig is NOT on the same circuit as the MW.

So here’s my main concern: When we had electrical work done, we had a whole-home Surge Protector installed on the box. Even now, the black cube reading “SYCOM” is sitting there smiling at me from under the box, shining its little green light.

My questions are:
1) Why didn’t the WHSP do its job? Is it possible that the surge was small enough that it went undetected but was large enough to damage two devices?
2) Is it possible to test the WHSP? Should I be filing a claim with the mfg or electrician who installed it?
3) While I’m sure the MW is dead, because I was there when it exploded like one of those cigars in a magic shop, what about the Keurig? Possible it’s just a fuse? Worth trying to take apart to check?
4) I suppose I should consider myself lucky we lost the $450 microwave and not the $2,400 fridge. Is this the type of situation where I should justify replacing the normal breaker with a breaker/surge protector, just for extra protection?

Thanks for the help!
 
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Old 06-12-18, 06:30 AM
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Yes it is possible that the surge was small enough to go undetected but large enough to damage some devices.

Do you have any incandescent plug in lights? You might want to test for a bad neutral, by trying the light in one receptacle while turning on a hair dryer in a receptacle in a different room. Try severl combinations and watch for unnatural brightening of the light. A bad neutral can cause random frequent everyday power surges that a whole house surge suppressor might not pick up.

A surge suppressor is a device that under normal conditions and normal voltages will draw negligible current itself but if voltage goes above a certain threshold value the surge suppressor acts like a short circuit that draws enough power to cause a voltage drop. Should the surge be of a high enough voltage or last a long enough time the surge suppressor will burn out sacrificially at that moment.

There are no easy and safe ways to test a surge suppressor nondestructively, namely not have it sacrifice itself during the test. What you would do is turn off your main breaker and also unplug or disconnect every light, appliance, and other device. Then using a separate 120 or 240 volt AC power source such as a generator together with a variable autotransformer, and, yes, a suicide cord, energize the system. With a voltmeter connected, raise the voltage a tad above 120 or 240 whichever you were testing with just for a moment (less than a second) and quickly turn it back. Observe whether the voltmeter reading followed what you did. Repeat the momentary burst (or artificial surge) going a little higher, then a little higher. At some point, probably around 140 volts or 280 volts respectively, if you see the voltmeter not going higher even though you turned the autotransformer up higher, that is an indication of the surge suppressor doing its job.
 

Last edited by AllanJ; 06-12-18 at 06:55 AM.
  #3  
Old 06-12-18, 07:02 AM
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Whole house surge protectors are mainly for protection from power company line voltage surges not lighting strikes. Lighting strike voltage can be induced through the ground wire and not even pass through a whole house protector and zap something. The whole house surge protector can help in some case for lighting strikes but is not full proof.
 
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Old 06-12-18, 08:06 AM
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If the microwave oven does not allow even simple manual start-stop operation without the clock having been set or reset then some failed components might not show symptoms until just after the clock is reset.
 
 

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