a companion discussion area for blog.codinghorror.com

Power, Surge Protection, PCs, and You


Simon: Yes, especially if it’s a surge due to a lightning strike.

I’m surprised that nobody’s mentioned the difference between “power conditioning” devices and “surge protectors.” Surge protectors (and most UPSes) do nothing to provide clean power. There’s a reason why musicians and hospitals don’t simply use tripp-lite or APC.

UL1449 is about the safety of the device, it’s acceptable for a tested device to fail, but it shouldn’t start a fire or create a shock hazard.


I got that isobar thing in the 90’s and paid about $80 from Ingram Micro after reading an article where they surged different protectors and the vast majority of them totally failed except for the Tripp Lites. It’s one of those instances of quality constrution with metal construction, a solid feeling switch and snug gripping receptacles. It’s supposed to condition the power as well. I still use it… wonder if it’s still good…better be I paid $80 for it.


Very enlightening stuff here.

I have been replacing circuit boards in my Raynor Flitestar garage door opener with regularity. I have replaced about 1 per year in 6 years, each time following a close lightning strike in the woods where I live.
I have always followed the directions from Raynor, and have the unti plugged into the “suppressor” they provided.

  1. I know why that rascal is worthless now. Thanks to you.
  2. I always felt that a UPS or similar equipment would help. (it would have to be screwed to the ceiling or in the panel)
  3. The last time I think it came in the ground circuit. A stereo and oscilloscope that were plugged into a GFCI outlet that tripped were both fine. The door opener is not on a GFCI.

So I suppose I will get a UPS and screw it to the ceiling, but I found a company called brickwall, that has info on how its equipment works. It sounds cool, but it’s pricey ($180 for a 15A 2-outlet)
My question is; with circuit boards at $85, do you think their “huge inductor and capacitors” filtering will help, or are my circuit boards the sacrificials here?

Mike Perry


That last sentence was poorly worded.
The Flitestar boards are $85 each,
The brickwall power surge suppressor is $180,
and the real question is whether they are blowing smoke to sell products and if I should just keep replacing boards.


Mike Perry


My firm is a specialized distributor of “Power Quality” products, ie we have leading technology for EVERY type of electrical disturbance. Rarely does one band-aid fix every problem.

UPS’s are strictly for outages, brown-outs and loss of power. UPS units have transient spike protection to protect themselves, not your critical load. I strongly suggest adding a surge bar to the load side of your UPS in every case.
Whether the UPS is “stand-by” or “always-on” it diverts surges to ground to protect the battery, charger and rectifier. NO UPS re-creates the neutral or ground circuits but merely uses them as diversion pathes for damaging spikes. Spikes are bi-directional and the neutral is the incursion highway for spikes to enter your computer bus.

Official terminology is: a transient is 8ms or one half cycle.

Static electricity is a transient spike capable of as much as 5000volts. How is your UPS going to protect your PC tower if your touch you keyboard or PC chassis?

According to IBM over 88% of all electrical disturbances are transient spike related. If money is limited, dollars are far better spent on transient spike protection.


I protect my server with a UPS. But I have lots of workstations that I’m not as worried about. After a UPS battery dies, would it make sense to use the serge protection side of the ups as just a surge protector?


Right - short of a $200 Brick Wall, a proven supressor made with quality components and a real “Working” light (like a $50 Ultra) with a $50 Tripp Lite 550VA will offer a boatload of real world protection and short-term backup power.

But the surge suppressor protects the UPS, you don’t want a SS after the UPS. Also nothing power hungry like a printer or lamp.


This is a little late, so I don’t know if know when you get comments on old entries. You can now by power panels for your home that have surge protection built in. This will protect your entire house. I haven’t looked into the specifics so I don’t know if there is a part that you need to replace every now and then or if they use a different method. You can check your local Home Depot or other home store for them.


Hi Jeff, I really appreciated your article about surge supressors.I think that I will buy one of the Tripp Lite Isobars that you suggested. My question is-does this unit have connections for coax in and out to PC? Can’t tell by pic. If not, what to do? My existing suppressor has these connections,but it surely not as good as what you are describing. Thanks much.GRM


One interesting note: voltage regulation in a UPS is largely unnecessary with PCs due to the ability of the switching power supply to accomodate voltage swings. UPS manufactures push this dubious feature.


Surge Protectors prevent spikes in power shorting out expensive equipment because they take the hit, not the eletronic device. The protector will not help you out against a lightning strike because of the amount of voltage coming in as the lighting will flow until it grounded. It will eaily jump through the surge protector if it is inline from the strike. A lightning strike has a much higher amount of voltage coming in than the power lines off the street. If your worried about lightning, the best defense is a lightning rod grounded into the earth away from the power coming off the street.

If you leave your computer on all the time, a UPS is much better solution, because it regulates the voltage coming in from the street, stepping down the highs (sometime a higher amount of voltage will come in off the street) and stepping up the lows (brown outs). It will give you a nice even voltage flow and prolong the life of eletronic equipment, and it also gives you a limited time of power during a blackout for graceful shutdowns etc. This is in addition to surge protection.


Also, has anyone ever had a power spike that the surge protector caught? Just wondering.

I never had, but I have had brown outs and over voltages occur on a regular basis that the UPS deals with.


@codinghorror can you check out the dead links on this article. Computer Power User is only available on webarchive https://web.archive.org/web/20090306035229/http://www.computerpoweruser.com:80/editorial/article.asp?article=articles/archive/c0305/07c05/07c05.asp