Surge Protectors
in [Repair]
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From: Grant on 9 Jun 2010 18:13 On Wed, 09 Jun 2010 10:36:52 -0500, bud-- <remove.budnews(a)isp.com> wrote: >westom wrote: >> On Jun 7, 2:56 pm, bud-- <remove.budn...(a)isp.com> wrote: >>> Some equipment, like TVs are tested to fail safely - it is not practical >>> to test whether they work. >> >> Which is what UL testing does. It tests for human safety. Does a >> protector have to be working after all tests? No. > >westom (aka w_tom) is a well known internet nut on a religious crusade >to eliminate the scourge of plug-in suppressors. He is here because he >uses google groups to look for "surge". > >As I said previously (and westom conveniently did not include), UL >requires that suppressors - plug-in and service panel - be fully >functional after a series of 20 test surges. They can fail only during >later tests that determine they fail safely. Do they fail to known state? Open or short? App. note showed a test rig with individually fused varistors, so I'm thinking they fail shorted? Grant. -- http://bugs.id.au/
From: Jim Yanik on 9 Jun 2010 18:51 zekfrivo(a)zekfrivolous.com (GregS) wrote in news:huogl7$rhq$1(a)usenet01.srv.cis.pitt.edu: > In article <8b8a$4c0fb589$cde8d56a$17907(a)DIALUPUSA.NET>, bud-- > <remove.budnews(a)isp.com> wrote: >>westom wrote: >>> On Jun 7, 2:56 pm, bud-- <remove.budn...(a)isp.com> wrote: >>>> Some equipment, like TVs are tested to fail safely - it is not >>>> practical to test whether they work. >>> >>> Which is what UL testing does. It tests for human safety. Does a >>> protector have to be working after all tests? No. >> >>westom (aka w_tom) is a well known internet nut on a religious crusade >>to eliminate the scourge of plug-in suppressors. He is here because >>he uses google groups to look for "surge". >> >>As I said previously (and westom conveniently did not include), UL >>requires that suppressors - plug-in and service panel - be fully >>functional after a series of 20 test surges. They can fail only during >>later tests that determine they fail safely. > > > I have been thinking of putting a main surpressor in the breaker box. > When I moved in the power company said there was one > installed in the meter, and if I wanted to continue using > it it would cost so much per month. i didn't of course, but I wonder > if they really took it out. ?? > > I put a couple in in the old house on the telephone lines > to ground on the main wooden panel after I destroyed a modem. > Never had any know hits after that though. > > just last week guy here said his surge surpressor exploded as a hit > happened outside the house. His TV still works. > > > greg > I've had power supplies in TEK pro video equipment have the MOV blown apart and the line fuse blown after a lightning strike,and the PS work after replacing the fuse and MOV. I had one TSG-170A burn a hole in the PCB from the MOV failing,and after filling in the hole and a new MOV and fuse,the PS worked. Central Florida gets a lot of lightning strikes. We're the Capital of the US in that respect. -- Jim Yanik jyanik at localnet dot com
From: GregS on 10 Jun 2010 09:10 In article <73eee$4c100259$cde8d5ab$12056(a)DIALUPUSA.NET>, bud-- <remove.budnews(a)isp.com> wrote: >GregS wrote: >> In article <huon5i$sut$1(a)usenet01.srv.cis.pitt.edu>, > zekfrivo(a)zekfrivolous.com (GregS) wrote: >>> In article <98a90$4c0fd58a$cde8d56a$23427(a)DIALUPUSA.NET>, bud-- >>> <remove.budnews(a)isp.com> wrote: >>>> GregS wrote: >>>>> In article <8b8a$4c0fb589$cde8d56a$17907(a)DIALUPUSA.NET>, bud-- >>>> <remove.budnews(a)isp.com> wrote: >> >>>> As I said previously, if you use a plug-in suppressor all external wires >>>> to a set of protected equipment need to go through the suppressor - >>>> power, phone, cable, .... This prevents high voltage between the wires >>>> to the protected equipment. >>>> >>> I have to recheck my cable for ground. I still have a telephone to the house >>> unused, >>> and an old unused Comcast phone box unused. Also the battery power >>> supply backup which I am going to use for my house emergency >>> lighting. >>> >>> I just checked, and its difficult to find surpressors that are cheap. >>> I found one for $30 and might get a discounted price. >>> This is a basic model.................. >>> http://www.grainger.com/Grainger/items/1ECD1?Pid=search > >I wouldn't call $30 for a service panel suppressor expensive. The 2 >plug-in suppressors I am using cost about $30 each. You appear to be >looking for Cydrome's "cheap-o" suppressors. I said I found a cheap one. I found another model with a lot higher rating. Most surpressors sold are almost $200. It seems while searching, there is a trend to upgrade to higher current ratings. But, a little Tripplite portable laptop surpressor has a really high rating in Joules. ?? http://www.amazon.com/Tripp-Lite-TRAVELER-Suppressor-Transformers/dp/B00006B83F >The IEEE surge guide recommends - for homes - ratings of 20-70kA, or for >high lightning areas 40-120kA. All the MOVs in the 2 plug-in >suppressors I have are rated higher than the Grainger suppressor. I have >never heard of ICM. > >> >> I always thought local surpressors were good to protect from motorized > equipment >> and keep things common mode and to ground. > >Motors are not a particular surge threat in a home. The #1 hazard is >lighting. The #2 threat is normal and abnormal utility switching >operations, including switching power factor correction capacitors. >Equipment, in general, has somewhere over 600-800V immunity from surges >(from Martzloff). > >> >> I might have a lack of available breakers, and I am thinking I >> allready have an outlet near the box on one 120 side. i might put in another > outlet on the other >> 120 side and use plug in replacable MOV's. I don't see much difference in >> using separate breakers vs protecting lines allready in use. > >If I am reading you right, you want to protect the service with plug-in >suppressors. Bad idea. I wrote earlier that the impedance of wire at >surge frequencies greatly limits the current. There is a high voltage >drop along the wire. The clamp voltage at the panel will be far higher >than the voltage at the suppressor. This is also an issue for panel >mounted suppressors. See the section on lead length in the IEEE surge >guide starting pdf page 31. > >If plug-in suppressors have a very short branch circuit length to the >panel they should have high ratings. > >I believe at least some service panel suppressors say to wire them to >existing circuits/circuit breakers. >
From: bud-- on 10 Jun 2010 10:26 Grant wrote: > On Wed, 09 Jun 2010 10:36:52 -0500, bud-- <remove.budnews(a)isp.com> wrote: > >> As I said previously (and westom conveniently did not include), UL >> requires that suppressors - plug-in and service panel - be fully >> functional after a series of 20 test surges. They can fail only during >> later tests that determine they fail safely. > > Do they fail to known state? Open or short? App. note showed a test > rig with individually fused varistors, so I'm thinking they fail shorted? Normal failure mode is that as MOVs deteriorate (past the defined end of life) the voltage at which they start to conduct goes down until they conduct on 'normal' voltage. That produces heat and they go into thermal runaway and wind up as a low resistance or short. I would expect this is after (not during) a surge. The thermal disconnects required in UL1449 listed suppressors disconnect MOVs when they fail. If this is a fuse I would expect it is in close proximity to the MOV. The IEEE surge guide shows that for plug-in suppressors, the protected load can be connected across the MOVs, and be disconnected if MOVS fail. Or the protected load can be connected to the incoming line and remain powered if the MOVs are disconnected. I want the former. -- bud--
From: westom on 10 Jun 2010 11:19
On Jun 10, 9:10 am, zekfr...(a)zekfrivolous.com (GregS) wrote: >> But, a little Tripplite portable laptop surpressor has a really > high rating in Joules. ?? How many hundred joules? Destructive surges are hundreds of thousands of joules. How does that Tripplite magically make all that energy disappear? It doesn't. That $3 power strip with some ten cent protector parts is selling for how much? Appreciate its purpose. Go to Lowes. Ask him for the Cutler-Hammer 'whole house' protector that costs less than $50. That protector (model CHSPMICRO) is for 50,000 amp surges. Don't take my word for it. Read the numeric specs. It will connect a direct lightning strike harmless to earth if connected to a breaker box that connects 'less than 10 feet' to earth ground. Massive energy dissipates harmlessly in earth. That Cutler- Hammer protector is required to protect the Tripplite. It is always about where energy dissipates. Why does that Tripplite numeric specifications not list protection from each type of surge - in numbers? Because it only claims to protect from surges that are typically not destructive. How does its hundreds of joules absorb surges that are hundreds of thousands of joules? Ask bud for those specs that claim protection from each type of surge. He will never provide those specs. A protector is only as effective as its earth ground. Which is why the Cutler-Hammer protector - about $1 per protected appliance - is also the superior solution. |