Am I Taking Too Much of a Risk?

[tjaymadison]

Someone I know -- who could be the poster boy for "A Little Knowledge Is Dangerous", if the job's open -- told me something I haven't been able to verify after some investigating and searching on the Web. He said that it's not good to plug one of the common, garden-variety, off-the-shelf surge strips into an outlet on another surge strip, making a two-piece extension cord, so to speak. He said that doing this defeats or negates any surge protection because the MOV's/varistors undergo some kind of "destructive interference" or "impedance feedback", but that it's OK if the second strip in the chain is just a power strip with no surge protection. Of course when I asked him where he heard/read this, he couldn't remember. Not being that well-grounded (pun intended) http://www.PCGuide.com/ubb/rolleyes.gif in theoretical electrical principles beyond Ohm's Law, I was sort of concerned, because my setup does have a surge strip plugged into an under-monitor power center. His claim has just enough of a ring of truth to it that I tried to track down some info, but had no luck unless I could wade through equations filled with a fraternity of lambdas, rho's, sigma's, delta's and omega's that was all Greek (again intended, sorry) to me anyway. So, to make a long story short (too late for that now), are there any EE's or physicists out there who can shed some light on this for me? Am I taking a chance by doing this? Thanks.

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"When I nod my head, hit it with the hammer."
-- (Moe, holding nail, to Curly, holding hammer)



[This message has been edited by tjaymadison (edited 05-03-2001).]

[mjc]

Without getting technical, yes two surge protectors in series (essentially what you're doing), besides being unecessary, can cause one or both of them to burn out. There is a similar post in one of the other categories, about a month or so ago......

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

[sea69]

hey http://www.PCGuide.com/ubb/smile.gif

well I can stand to be corrected here, as I'm not an electrician... but I was told nothing like this when I asked the same question.

What I was told was that with TWO surge protectors (one plugged into another) that the only thing to be aware of was that I would not have double the protection, ... that I would have the protection of the ONE that had the HIGHEST jouels (spelled wrong?).. not the added/combined protection of BOTH.

after that I never gave it a second thought (until now) http://www.PCGuide.com/ubb/eek.gif

both of mine are / have been plugged in since day one on this machine.. and both lights (green and Red) are still lit on both, so I assume that both are still in correct working order.

http://www.PCGuide.com/ubb/smile.gif

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sea1_69@hotmail.com

homepage (http://www.seanweb1.homestead.com/3.html)

[This message has been edited by sea69 (edited 05-04-2001).]

[mjc]

Generally what'll happen is one of the surge protectors will just quit, adding a plain (non-protected) power strip shouldn't be a problem unless you have so many things plugged in that it goes over the power rating of the protector, also if you take and plug two surge protectors into the same outlet (or plain power strip), no problems.

I don't know about all the different manufacturers, but the instruction sheet for mine said don't, that there is risk of damage to the protector.

My basic thoughts are: If it increases the chance of the surge proctector failing, probably when you need most, then why do it.

Also a couple of colleges turned up on Google prohibting the "piggy-backing" of surge protectors for safety reasons.....

And from Belkin Tech Support "It doesn't comply with our warranty, but there is no risk of damaging our protectors by doing so, but the risk of overloading the protector is greater and the risk of damage from that is greater. There is no advantage to doing it and it compromises the warranty." (tech support guy I talked to said that Belkin's protectors wouldn't be damaged but he didn't know about other manufacturers....)

So I would say that there is some risk of damage (how much probably depends upon the quality of construction) or the maufacturers wouldn't say that it goes against the warranty.

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

[This message has been edited by mjc (edited 05-04-2001).]

[sea69]

"Doh"...... now what do I do with the box of surge protectors from Hopkins??

I was going to throw a 'Surge Protector' mixer...and invite the nieghboors.. you know ??... but now........... http://www.PCGuide.com/ubb/frown.gif

hehe http://www.PCGuide.com/ubb/wink.gif

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sea1_69@hotmail.com

homepage (http://www.seanweb1.homestead.com/3.html)

[kayofcircles]

We live in boonies where power outage is daily..or at best, weekly..so we bought UPS backups for both our puters. Elton plugged his into a surge protector because couldn't reach the outlet. I asked APC about it, and they said that we had absolutely NO warranty if the UPS was not plugged directly into the wall. So, Elton had to install another electrical outlet in that room.

We have surge protectors on practically everything in the house, but I'll bet you that if they failed and something got blown, I wouldn't be able to find those warranty cards anyway.

[Neil_MO]

I was having problems with my cable modem recently and one time when I called (I called tons of times to get this fixed to no prevail) the technical support person asked me if I had my cable modem plugged into a surge protector. He said that the cable modem had its own surge protector and that if I plugged my modem into a surge protector then then they can cancel each other out (or something to that effect). I didn't really know if I should believe him or not (many of those techs seem to have no idea what they are talking about). Anyway, I plugged my cable modem directly into the wall and my problem still continued.

[damfino]

WELL , my brotherinlaw (a journeyman electrian)
says NO WAY ! One defeats the purpose of the
other. My UPS says : Never ever , Warranty VOID!!!
A short power strip W/15amp breaker OK .
BOB