Joules and surge protectors

considering i'm electronics / electrically illiterate, i figured i'd ask this question here.

Just had a surge protector burn out during a lighting strike - nothing plugged into it was fried but it was. So i was looking at replacement strips and noticed the cheaper ones are showing like "40 joule protection" and the more expensive ones 400-700 joule protection.

THen out of curiousty i looked at the specs on my CyberPower UPS, and it lists 2800 joules

so, am i correct in assuming that the more joules, the stronger a spike in current the strip can handle without frying? If that's the case, it would seem to be half dozen of one and 6 of the other in terms of which to buy - if the surge protector fries at 40 joules but in frying saves the equipment plugged into it, what's a higher rated (and more expensive) surge protector strip doing but saving me the inconvenience of having to buy a replacement surge strip?
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  1. Best answer
    More joules is required for higher power equipment. Higher joules also last longer. If that ups was plugged in during that lightning strike, it's not at 2800 joules anymore. They also decrease over time. You should worry of those that are that low joules (40 joules) or cheap. They tend to not actually do any protecting.
  2. thanks - the UPS didn't suffer any damage nor the items plugged into it (computer, unmanaged TrendNet PoE switch & monitor) and it's plugged directly into the wall receptacle. The surge protector was carrying all the other peripheral equipment (cordless phone, external BD player, credit card machine, a couple of desk lamps - items like that.

    Is there a recommended "minimum" joule protection? When this one went, we had a number of "booms" coming from the transformer at the back of our property, during the windstorm that came thru last week (i'm on the east coast) and power went out and came back on a number of times - the 3rd time it went out, it was out for 9 hours before power was restored.
  3. There's not much of a minimum but the cheaper ones are in the 700 area. You can even find some around $10 from good ol' apc. I'd rather have something decent that I can trust and will last awhile. It'll save in the long run and that doesn't apply just to surge protectors.
  4. thanks
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