How to Choose a Surge Protector

Now that you are more aware of power problems and the various solutions, we recommend the following approach in choosing a surge protector. This approach eliminates the "technitalk" and confusion that the selection process could entail, and, hopefully, will demystify the selection process.

Step 1.
What are you protecting? How valuable are these products? With computers, also consider the value of your data; a surge can destroy it all, as well as causing significant equipment damage. Even home telephones, with telephone numbers in memory will lose the "programmed" telephone numbers to a surge. The same is true with programmable VCR's and TV's.

You should also consider power protection for other conduits of surges. Surges are not limited to AC lines. TV and telephone cables can also carry transient surges. Therefore, any equipment such as a VCR, TV and HiFi System connected to an exterior antenna or CATV cable deserves protection. The same can be said for telephone lines acting as a conduit for surges. Equipment connected to these lines; telephones, modems, faxes--; need telephone line protection as well as AC line protection.

Once you have reviewed the equipment to be protected, the cost of repair or replacement, loss of productivity, business or enjoyment, and the inconvenience to get the equipment repaired or replaced, you can then assess how much "insurance" you need. The more "insurance" you need, the better the protection and the greater the cost.  

Step 2.
Look at the UL 1449 Suppressed Voltage rating. This number reflects the amount of volt age the surge suppressor will let through to your connected equipment after "clamping". The lower the rating, the better.

500V - Good 400V - Better 330V - Best

Step 3.
Stages of Protection/Surge Current Rating. UL 1449 is great as far as it goes, but it does not tell you how much surge current (in amps) can be handled or how quickly the suppressor will clamp. With multiple stages of protection, different components are used to sup press a surge. The more stages, the more surge current can be handled.

1 stage - Good 2 stages - Better 3 stages - Best

The surge current rating in amps lets you know the maximum amount of surge current that can be safely handled by the suppressor. The higher the number, the better.

Step 4.
Clamping Response Time.

How quickly does the suppressor respond--the faster the better.
- Nanosecond (billionths of a second) - Better
- Picosecond (trillionths of a second) - Best

Step 5.
Incoming Lines Protected--The more, the better.
1 line (Hot to Neutral) - Good
2 lines (Hot to Neutral, Hot to Ground) - Better
3 lines (Hot to Neutral, Hot to Ground, Neutral to Ground) - Best

Step 6.
Warranty. A summation, of sorts, regarding the pluses" of a manufacturer's product. The longer the better. Especially look for products that feature lifetime warranties and equipment replacement guarantees.


What you Need to know about MOVs
And perhaps what you wish you never knew...
(Information supplied by Zero Surge)
The heart of many surge suppressors available today is a small electronic component called an MOV (Metal Oxide Varistor). Follow this link to find out more about MOVs. their serious shortcomings and performance limitations.
 
The role of the MOV is to divert surge current, however, MOVs wear out with use. As more surges are diverted, the MOVs life span shortens, and failure becomes imminent. How soon? How many surges can they handle? No one knows until failure occurs!
There is no forewarning or visual indications given - just failure. And while failing, they can reach very high temperatures, and actually start fires. See examples of catastrophic MOV failures in the photos below.
This MOV (the yellow disks) fractured cleanly. Surge protection is lost, and the "protected" computer was severely damaged, but there is no fire danger. This unit continues to deliver power, and all lights and switches operate without any indication of failure.
This model is an example of dangerous construction, where failed MOV is packed too tightly between adjacent components and cannot split open. This unit is still a live short circuit and sparks violently when plugged into a live receptacle.
Plastic cased MOV surge protectors below show identical burn failures. Left unit was found smoking under an office desk, nearly on fire. Both units continued to deliver power without indication of any problem.
You're betting your precious computer on this!!!
Circuit board removed from plastic case, showing all 6 MOVs (yellow disks). One leg of each MOV has been cut and there is therefore no protection, but "Protection Working" LED continues to glow green.
All 6 MOVs removed from circuit board, but "Protection Working" LED (immediately above large yellow capacitor) remains lit.
Industry experts estimate surge probabilities in terms of thousands of surge occurances. What do MOV manufacturers publish regarding their product's surge capability?
 
This table shows three manufacturer's surge ratings for two popular sizes of MOVs used in surge suppressors.
 
Metal-Oxide Varistor Endurance Ratings
Panasonic Siemens Components, Inc. Harris Semiconductor
14mm MOV 10 surges of 1,000 amps 10 surges of 1,000 amps 10 surges of 1,000 amps
20mm MOV 100 surges of 1,000 amps 100 surges of 1,000 amps 100 surges of 1,000 amps
A "best case" rating is 100 surges - far under the new commercial standard of 1000!