Surge protection help needed

Hi
We have an office with a spur, single-phase 240v 30A that feeds several computers etc.
Rather than buy an individual Belkin or similar surge protector trailing
socket for each item of equipment, I'd ideally like to put a single surge protector / voltage regulator in line to protect the lot. But, I'm confused about what is the best option to go for on the UK market. Various products can be found by Googling, but I'm concerned that they may not provide the right protection.
Any help would be much appreciated.
Cheers
Brian Abbott
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Plug-in UPS does not even claim to protect from the type of transient that damages computers. Any protection provided by that UPS is already inside a computer power supply. Furthermore, the plug-in UPS connects computer directly to AC mains when not in battery backup mode.
Do not assume a surge protector is going to stop, block, filter, or absorb a surge. Simply the urban myth used to promote ineffective protection such as the plug-in UPS. Concepts that will become obvious in newsgroup discussions cited below.
Computer already includes sufficient protection - without any UPS or power strip protector. But that internal protection assumes a destructive surge is earthed before entering a building. It's called 'whole house' protector. Every incoming wire must connect to earth ground - either by hardwire connection or via a 'whole house' protector - at the service entrance. Effective protector costs about 1 per protected appliance. Some examples: http://www.keison.co.uk/furse/furse06.htm Same is also required for other incoming utilities such as phone line: http://www.keison.co.uk/furse/furse08.htm http://www.one.co.uk/catalogue/telebyte/LightSurgeProtect/22PX.HTM
Fundamentals are explained in the newsgroup alt.certification.a-plus entitled "Opinions on Surge Protectors?" on 7 Jul 2003 or at http://tinyurl.com/l3m9
Critical to effective protection is single point earth ground located when those utilities enter building. Further technical information provided in discussions at: http://tinyurl.com/p1rk , http://tinyurl.com/ghgv , and http://tinyurl.com/ghgm
Bottom line - no earth ground (such as that recommend plug-in UPS) means no effective protection - which is why that UPS (and those who recommend it) does not discuss earthing and avoids mentioning the different types of transients. A surge protector is only as effective as its earth ground - which is why those above discussions should be read starting with "Opinions on Surge Protectors?".
Brian Abbott wrote:

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Thanks for that w_toml. Very interesting.
Around where we are lightning strikes are pretty rare, but we can count on a blackout 1 or 2 x per year. I've always unlpugged anything like a PC in these circumstances to avoid the surge when power is reconnected. How much of a concern is the reconnection surge? Does the same rule about effective earthing apply?

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Power restoration is a surge of current; not a voltage surge. With so many things taking full power simultaneously, load is just too large to create excessive voltage. Furthermore, appliances must withstand in excess of 600 volts transients. Computer power supplies typically withstand on the order of 1000 volts differential and 2000 volts common mode transients; without damage. If suffering voltages that large when power is restored, then every GFCI, electronic timer switch, clock radio, etc also requires replacement.
Have not observed it, but another possible source of serious common mode transients is said to occur when a utility main breaker trips. Therefore it would not be power restoration that was the problem; but a common mode transient during power loss.
Brian Abbott wrote:

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What I believe you are talking about is a spark gap device I believe. But let me clue people to one thing. We hear about using a common ground. But that is really wrong when designing electronic equipment. First each circuit, particularly input and output circuits should have their own wire to the common ground. Second in swithching power supplies and other devices that switch. the return wire should be to the switching device and then that loop should be returned to the common ground point with out carrying any other ground currents, so switching current generated voltages are not impressed on other circuitry. This is often a source of ripple and oscillations. I went through this when I had to teach a class at Kennedy space center on how to make measurements between points above ground.
In fact I suggested the use of Battery operated scopes as differntial scopes often did not have enough common mode rejection.
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confused
products
If your really worried about protecting them then your going to need 2 areas of protection. One at the panel and one at the unit itself. That is what the IEEE recommends for protection. I realize that you have slightly different standards but not that much different. OR Bite the bullet and put in a big UPS that has voltage regulation and surge protection.
Remember if you have Ethernet going out from where these machines are and going to a machine fed from another panel/source, you can get a difference in ground voltages. If you have this condition please consult a professional. It will be worth the money and time.
Sorry I do not know of a simple/cheap solution
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