computer Surge Suppressor-protector question

Page 5 of 5  
wrote:

Well, a big flaw in that thinking of mine. The pdf file someone posted says
"These outlet protectors usually have an LED which informs the user that the protector is no longer working and must be replaced. Unfortunately, nature does not always cooperate with this approach."
THIS IS THE IMPORTANT PART:
"Most lightning strokes are not just singular, but consist of several strokes spaced milliseconds apart. The electronic equipment is likely to be damaged before the homeowner replaces the protector."
I shoudl have bought a better one, although I don't know if the Intermatic for 130 or 160 is really better.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/13/2011 11:30 PM, mm wrote:

Not always as bad as it sounds, many MOV's just become a dead short and blow the breaker. I've also opened up some protectors and added a couple more MOV's parallel. Radio Little Run Down Building used to have two kinds of 130V MOV's, of course get the bigger ones if you have the space.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tony Miklos wrote:

UL1449 (since 1998) requires a disconnect for overheating MOVs. The protected load can be connected across the MOVs, so it is disconnected with the MOVs. That way the protected load does not loose protection (although it will loose power). Some suppressors have warranties for protected equipment. Plug-in suppressors with a warranty are likely wired this way. (Obviously you can't do this with service panel suppressors.)
Or the protected load can be connected ahead of the MOV protection. The protected load would then stay powered without protection. According to the IEEE surge guide, plug-in suppressors wired this way now are required by UL to be identified.

Anything with a UL label built since 1998 has built in disconnects for failing MOVs.
IMHO changing a suppressor violates the design and is a safety hazard. There are a lot of things I would fix or change. A suppressor is not one of them.
--
bud--

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/14/2011 12:39 PM, bud-- wrote:

I did see a change inside some equipment where they put a fuse before the MOV. Would this have anything to do with new code? (It is inside the equipment) If I were to make one extra safe, I'd put a few fuses in series with a MOV parallel after each fuse.

A MOV parralell across the hot and neutral is pretty basic stuff and doesn't get much simpler. But yes, if you don't know basic electronics maybe you shouldn't do it. Putting in a larger rated MOV or several MOV's in parallell is like what many people do by plugging a surge suppressor into another surge protector for better protection. Or plugging in a multi outlet strip with surge protection into a surge protector and then to the outlet. Any dangers with those idea's too?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tony Miklos wrote:

The disconnects, specifically in surge suppressors (not 'equipment'), are to prevent the suppressor from being a fire hazard. The disconnects are likely near the MOVs to respond at least partly to MOV heat. A normal fuse may work. But the whole thing, in a competent design, provides overheating protection while not disconnecting until the MOVs are failing. It is an engineered product.
I used to use a homemade plug-in surge suppressor. It included a fuse. I decided it was not as safe as I wanted.

For best device life you want the surge shared by the parallel MOVs. Since MOVs are not precision devices that is not likely to happen unless the MOVs are matched, as from the same batch. If one MOV takes most of the surge hit (likely in a random pairing) you may not get much advantage from the second MOV. The first MOV can die (shorted) while the second MOV has much of its life left. It is basic electronics.

UL does not intend for them to be daisy chained. You are not likely to find a manufacturer that would say it is OK (and it is probably explicitly prohibited in the manufacturer instructions).
As above, daisy chaining does not necessarily work the way you expect.
You can get plug-in suppressors with high ratings for not much money. I don't really see a reason to take chances on compromising surge protection or fire protection.
--
bud--

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Yes, they got pretty mad at me in sci.electronics.repair when I suggested that I would repair my whole-house suppressover if the MOVs blew.
My theory was that would justify my buying an expensive one, if I knew I coudl keep it running, but they didnt' like that and no one defended my position.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Exactly what would that "sophisticated electronics" be? AFAIK, most surge protectors use MOVs because they are the device best suited to handle surges.

I can show you surge protectors from major manufacturers that cost hundreds of dollars that use MOVs.

And guess what they use? MOVs
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 13 Mar 2011 04:50:11 -0700 (PDT), " snipped-for-privacy@optonline.net"

You're right. I didn't buy the wrong thing!
Accordign to http://www.apsllc.net/Cooper%20Power/Line/Aug97.pdf
To eliminate this problem (the one I quoted in my preivous post), a utility grade surge arrester mounted at the service entrance absorbs the bulk of the energy from lightning surges, allowing the local surge suppressor to work properly. A durable, high-energy service entrance arrester helps ensure that other protective devices within the house continue to work for years.
The service entrance surge arrester also protects the wiring and electromechanical loads (washers, dryers,etc.) in the home from lightning damage.
Well my cheap one is whole house, so maybe it's somewhere in the middle?
If BGE has a utility grade surge arrestor for my house, I don't know how much they would charge.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I forgot. I don't know what it's like but the only one they have is 8 dollars a month, no installation charge. That's 100 dollars a year, every year.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
marco polo wrote:

It's at least as well protected with the switched turned off as with the switch turned on because the surge protection components are still connected to the AC lines.
But if a storm is pending or you'll be leaving your home, unplug everything connected to the computer, even the monitor, printer, modem, and TV cable.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Turning them off doesn't do much for lightning/surge suppression if anything. Ive never lost a 'puter to lightning but I have lost a TV and several piece of test equipment I left plugged into my work bench..... They were turned off . As an electronics repairman over the years I have repaired many lightning damaged devices where all I had to do was replace the MOV. While I cant say with absolute certainty that this protected the device as I also have may crispy fried circuit s that had lightning protection I would say that the evidence I have seen leans in that direction.
Jimmie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.