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Associate

Join Date: Jul 2006
Location: Northern Canada
Posts: 53

Power Bars

12/13/2006 2:06 PM

Here's what you electrical guys may think is a "dumb" question from a mechanical engineer. Does a power bar offer any protection for my TV, computer, PLC, etc. from a power surge, such as a lightning strike?

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Guru
Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: El Lago, Texas, USA
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#1

Re: power bars

12/13/2006 2:25 PM

If your "power bar" is one that's been designed as a surge suppressor, and if it's got a high enough suppression rating, then yes. If it's just a box with plugs connected to an extension cord, then no.

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Guru
United States - Member - New Member Engineering Fields - Power Engineering - New Member

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#2

Re: Power Bars

12/13/2006 3:53 PM

Just so you know, most of the ones that are inexpensive and widely available which say they have surge protection in them are very weak on the protection. They use components that work only until the first big surge, then they are no longer protecting and you don't know it. Look for the more expensive ones that have an indicator (usually a light or fuse) to tell you when the protective device has been sacrificed, and also one where the protective device is replaceable or the manufacturer will replace it when damaged. I like this one for that reason.

http://www.apc.com/products/family/index.cfm?id=131&tab=features#anchor1

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Guru
Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: El Lago, Texas, USA
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#3
In reply to #2

Re: Power Bars

12/13/2006 3:57 PM

You can also check the ratings. Best Buy used to sell a line of surge suppressors rated at 10,000J, 20,000J, etc., indicating the amount of energy they were capable of absorbing.

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Power-User
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#7
In reply to #3

Re: Power Bars

12/15/2006 3:00 PM

Just one thing to add:

Any surge suppressor is only as good as the ground
in your outlet. If you're worried, check that.

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Anonymous Poster
#4

Re: Power Bars

12/13/2006 11:44 PM

More importantly, a surge is only part of the answer as a brownout or momnentary outage may cause as much damage to equipment or loss of programing and data as the surge! A beter solution is a Battery back up or UPS that is not much more in cost but more than double the protection!

http://www.powerfactorinc.com/ups/powerware/pw3110.htm

or http://www.powerfactorinc.com/ups/powerware/pw3110.htm

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Anonymous Poster
#5

Re: Power Bars

12/14/2006 9:13 AM

Throw that piece of garbage away and buy a decent UPS. They can be had for a reasonable price and will protect against surges as well as brown outs and momentary power outages. Mine will run my computer for 15 minutes or so which is ample to shutdown with out data loss. It will even run my desk lamp while doing so. There are others big enough to go for several hours but I made an economic decision and went with the lower priced model. The biggest problem with the "power bars" is that the "protection" is Metal Oxide Varistor (MOV) based. MOVs are now stable with time or temperature and can actually degrade to the point where they conduct continuously leading to a kind of thermal run away and fire. Read up on the problem on the net then, get rid of it...

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Guru
Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: El Lago, Texas, USA
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#6
In reply to #5

Re: Power Bars

12/14/2006 10:22 AM

I've been using MOVs for years, and never had a problem.

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Power-User

Join Date: Dec 2006
Location: Buffalo, New York
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#8

Re: Power Bars

12/15/2006 4:17 PM

I agree that most "power bar" are cheap, and some even trip out when something is plug into it ( the REAL CHEAP kind.) I like the UPS with surge built in, like the kind APC make. As a note, during black friday (the day after Thanksgiving in USA), you can get a real bargin. I bought my APC UPS with 500VA for $20. It normally retail for about $60 where I live.

MidniteFighter

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