NA Family Joules NA

Jim Rosenow

Jim Rosenow

Line Up and Wait
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Jim Rosenow
Looking at new power strips to add USB plug-in functionality. Surge protection varies from 200 joules to over 4000 joules on otherwise functionally-equivalent units . I know it rates the degree of protection, but just how many joules does one guy need? :) Thanks!

Jim
 
There are three key parameters: speed of response (faster is better), clamping voltage (lower is better) and energy dissipation capacity (higher is better and this is measure in Joules).

Now, since I'm an engineer and this is POA: What's your mission? Meaning what are you trying to protect? Appliances? Computers?
 
laptops/phones/ipad/tablets....hey, we just went aviation-related!! Tablets are for FF/GP :)

Jim

PS- Just wondering what a reasonable range is....4000 joules are $25 each, 200 joules half that....
 
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Jim Rosenow said:
laptops/phones
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Those are pretty sensitive. I'd go more than 1000 Joules and look for something in the nanoseconds clamping time. Preferably clamping below 300V.

Also consider what else might be plugged in physically to the computer. If you use a wired network, get a surge suppressor on the network cable. If you've got a longer USB printer cord, make sure that's protected as well. Induced current in wires can fry a computer without ever hitting the power line.
 
Thanks for the info!..... Do they make something that would perform that function for the whole house? (Now I'm just getting lazy...should do my own research :)

Jim
 
Jim Rosenow said:
Thanks for the info!..... Do they make something that would perform that function for the whole house? (Now I'm just getting lazy...should do my own research :)

Jim
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Yes and no. Yes, they do (typically installed in the main panel), but for sensitive electronics there can be enough wire between the panel and the device to still zap things. The best approach is "defense in depth" where you have the one on the main panel (which will also help with appliances and air conditioners) and then a good one at the electronics as well.

I live in the lightning capitol of the world (central Florida) and I used to do the electrical work specified by a lightning consultant. Lightning does really strange things. But man is there a lot of energy in it!
 
I know whereof you speak! I lived in Stuart for awhile. Nice place, but glad (with no offense intended) I'm gone. Thanks again!

Jim
 
They by and large are junk if you don't have a way to see if the MOV has died for the cause. They'll fail open so it may be entirely useless after one surge.
 
MOV, Ron?..... and do I hear you saying they'll provide power without providing protection after a surge? Seems counter-productive!

Jim
 
Jim Rosenow said:
MOV, Ron?..... and do I hear you saying they'll provide power without providing protection after a surge? Seems counter-productive!

Jim
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The MOV (metal oxide varistor) is what lets the extra current/voltage go to ground. If they get hit to hard they fail (not uncommon) and tend to fail open-meaning no path to ground for the extra current/voltage. Good ones will have a light showing the failure. Better ones are made to stop working. Cheap ones have no indication.
 
It looks good.
 
If they're anything like the POS Tripplite UPS I had, you should toss them. Stupid thing caught fire.
 
flyingron said:
If they're anything like the POS Tripplite UPS I had, you should toss them. Stupid thing caught fire.
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I had a tripplite UPS shock the crap out of my coworker then catch fire. Garbage I tell you.
 
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