I dont know if this is the right place to ask this question or not. Ive recently bought a surge protector(those small square ones) and im gonna connect it to my Computer. Now the thing is that im not sure if its really a surge protector or not. Its cause i bought the protector online and ive read some reviews on the website about the protector and some of the reviews were not good. One even claimed that it was nothing but a simple connector.So, is there a way to check if the surge protector is functional or not, like from a multimeter or something, cause i really don,t want my cpu to fry. TIA!

  • You bought it "online" and you didn't link the product, so I gather it's just a random cheap one. Yeah, you got ripped off. You have to be a more discerning buyer. Try Tripp-Lite. May 16, 2020 at 4:33

2 Answers 2


The first problem is you bought it online. Was it from a reputable company? The comments online will always vary from excellent to terrible so you can't go by those. Most will protect against overload but a surge or spike is a different story

There's no real way to check these unless you can convince the power company to up the regulator on your feeder and cause a spike. Check the company you purchased it from and ask about warranties and register your purchase.

  • One quick question, Im not worried about lightning or anything frying my pc. Im more worried about voltage ups and downs. So should i rather buy a voltage regulator or is a surge protector the way to go? May 15, 2020 at 23:43
  • 2
    I'd be purchasing a regulator before wasting money on a surge protector. Better yet, I'd get a continuous UPS and run my cpu off of it.
    – JACK
    May 15, 2020 at 23:51
  • Thanks for the advice!....appreciate it May 16, 2020 at 0:44

Can the supplier give you a specification sheet showing what it protects against and what the component technology is inside of it? There are industry standards for Surge Protective Devices, (SPDs) administered by UL under standard number 1449 that separates them into different usage categories (hard wired, plug in, large, small etc. etc. If this thing is not UL 1449 listed, it is likely junk. If it is, then you would need to know which class it was and compare that to how you are using it.


This UL site can direct you to a database they maintain on all of the different manufacturers and suppliers by plugging in the data you have on it and seeing if it is there.

Even if it is listed, that doesn't mean it is good, it basically just means it was tested to some minimum standard and will not start a fire (which is really what UL is about anyway). But the general rule is that the cheaper it is, the less likely it is to be of any real value. Most cheap SPDs are just what's called an MOV (Metal Oxide Varistor), a device that only conducts when the voltage rises above a certain threshold.

So what happens is that a "spike" of voltage comes in from the utility line, it exceeds the threshold of the MOV and the MOV conducts to ground, protecting your downstream equipment. That does work, except that when it works, the MOV is often sacrificed in the task, meaning it only works once or maybe a few times (if the spikes are low), then it is vaporized and no longer there. But you can't tell from the outside, so you don't know. So in my opinion if you are going to buy one at all, buy one with some sort of indicator, usually an LED, that tells you when it has done it's job and is gone. That way you at least know you need to buy another one.

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