# How many joules is recommended for computer protection?



## annamaria (Nov 25, 2014)

I came across these questions on a forum and would like to know what some of your opinions are. I am looking to purchase several surge protectors for the small school I work at. Wanting something for a decent price. 

From what I have gathered there are several factors to look into for a surge protector.
1. Clamping voltage. Anything 350 volts and below is preferred. I have seen items with clamping voltages of 400-500 which can be too high for certain electronic devices.
2. Response time - < 1 nanosecond. Just the other day, I saw a surge protector with a response time of 1 second! Absolutely unacceptable! These spikes/surges and strikes of lighting happen almost instantly which means you need a device capable of near instantaneous action. It's really important otherwise those surges can damage your gear by the time your surge suppressor reacts.
3. Joule rating - I've read that a rating of 600 joules and above is what to look for.....and that's all I've found. What is 600 joules? How effective is 600 joules? A small spike? A long lasting surge?


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## Rick50 (Nov 25, 2014)

The joule is a reference for a unit of energy.
Joule - Wikipedia, the free encyclopedia

For computer protection what your asking is "What amount of energy am I trying to protect against?" All of the small plug -in the wall protection devices are just minimal protection. They will not prevent against serious energy like a lighting strike. Here is a list of recommended devices I found by search.
Top Rated Surge Protectors: Compare Reviews & Ratings from our list of Best Surge Protectors

A step up from this would be Transformer Isolation and battery backup.
An even higher level of protection involves a complete metal screen room designed to prevent energy transfer through the air. And of course all this just gets more and more expensive.

Here is a list of orders of magnitude of energy:
Orders of magnitude (energy) - Wikipedia, the free encyclopedia

So for me I wouldn't worry too much. At one point in my career I used transformer / battery backup protection but it never paid off. The idea was to protect against power loss so I wouldn't lose data I was working on when the computer crashed.

So my opinion is not to worry. If something serious happens you probably won't be adequately protected anyway.


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## annamaria (Nov 25, 2014)

Rick50 said:


> The joule is a reference for a unit of energy.
> Joule - Wikipedia, the free encyclopedia
> 
> For computer protection what your asking is "What amount of energy am I trying to protect against?" All of the small plug -in the wall protection devices are just minimal protection. They will not prevent against serious energy like a lighting strike. Here is a list of recommended devices I found by search.
> ...



Thank you so much Rick I appreciate it.  A few of our older XP computers were fried recently, they were not connected to surge protectors, so that is why I was worried.  We have just purchased 3 Computers that were upgraded to Win7 and don't want them fried


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## pgriz (Nov 25, 2014)

I have one of these at each computer:  Buy APC Back-UPS 450 - Technical Specifications and Information | APC

They've kept the computers (and network) running through multiple power outages, brown-outs, voltage spikes, etc.  When the AC power goes down for more than 10 minutes, it still gives me enough time to save everything, and do a graceful shutdown.  Since I've used these UPS units, we have not lost any computer, printer, or device, going on 5 years now.  Whereas before, I'd lose a computer (fried motherboard, or hard drive) or modem, or other device, about once a year.


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## Rick50 (Nov 25, 2014)

pgriz said:


> I have one of these at each computer:  Buy APC Back-UPS 450 - Technical Specifications and Information | APC
> 
> They've kept the computers (and network) running through multiple power outages, brown-outs, voltage spikes, etc.  When the AC power goes down for more than 10 minutes, it still gives me enough time to save everything, and do a graceful shutdown.  Since I've used these UPS units, we have not lost any computer, printer, or device, going on 5 years now.  Whereas before, I'd lose a computer (fried motherboard, or hard drive) or modem, or other device, about once a year.


In an area where "stuff" happens this is the best idea I think. The neighborhood I'm in now has not had any crazy events outside of a few power outages.


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## Rick50 (Nov 25, 2014)

annamaria said:


> Thank you so much Rick I appreciate it.  A few of our older XP computers were fried recently, they were not connected to surge protectors, so that is why I was worried.  We have just purchased 3 Computers that were upgraded to Win7 and don't want them fried


It's very possible that something pgriz has done is what you will need as well. If you have had computers get fried something is happening and just the small plug in protection devices may not be adequate. In thinking about it a bit I don't live in an area where we have severe weather, thunderstorms, etc. and so that may be why I'm doing OK.


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## annamaria (Nov 26, 2014)

pgriz said:


> I have one of these at each computer:  Buy APC Back-UPS 450 - Technical Specifications and Information | APC
> 
> They've kept the computers (and network) running through multiple power outages, brown-outs, voltage spikes, etc.  When the AC power goes down for more than 10 minutes, it still gives me enough time to save everything, and do a graceful shutdown.  Since I've used these UPS units, we have not lost any computer, printer, or device, going on 5 years now.  Whereas before, I'd lose a computer (fried motherboard, or hard drive) or modem, or other device, about once a year.



Thanks pgriz for your info and link I will give it a look. Let's see what the school decides to do, since we are on a limited budget.


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## annamaria (Nov 26, 2014)

Rick50 said:


> annamaria said:
> 
> 
> > Thank you so much Rick I appreciate it.  A few of our older XP computers were fried recently, they were not connected to surge protectors, so that is why I was worried.  We have just purchased 3 Computers that were upgraded to Win7 and don't want them fried
> ...



Yea we get surges quite a bit around the school area so definitely got to get something for protection.


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