Surge Protectors
in [Repair]
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From: bud-- on 9 Jun 2010 13:53 GregS wrote: > 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. ?? The utility suppressors I have seen are between the meter and meter box - there is a spacer between them. I would rather have my own service panel suppressor. The IEEE surge guide has advice for ratings and installation. They solve many, but not all, surge problems. They are a particularly good idea in high lightning areas. > > 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. As I have said several times, the NIST surge guide suggests that most equipment damage is likely caused by high voltage between power and phone/cable wires. In the US, telephone companies are almost always very good about installing an entrance protector that clamps the voltage on the phone wires to a ground terminal. The ground terminal needs to connect with a short wire to the ground at the electrical service. With a large surge the house ground can rise thousands of volts above absolute ground. You want all wiring - power, phone, cable, satellite - to rise together. This is stressed in the IEEE surge protection guide - very good information. A cable entry ground block also has to connect with a short wire - cable companies are not nearly as good as phone companies doing this right. And satellite entry ground blocks also have to connect to the power grounding system. Satellite installations can be even worse. 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. -- bud--
From: GregS on 9 Jun 2010 14:40 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: >>> 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. ?? > >The utility suppressors I have seen are between the meter and meter box >- there is a spacer between them. > >I would rather have my own service panel suppressor. The IEEE surge >guide has advice for ratings and installation. > >They solve many, but not all, surge problems. They are a particularly >good idea in high lightning areas. > >> >> 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. > >As I have said several times, the NIST surge guide suggests that most >equipment damage is likely caused by high voltage between power and >phone/cable wires. > >In the US, telephone companies are almost always very good about >installing an entrance protector that clamps the voltage on the phone >wires to a ground terminal. The ground terminal needs to connect with a >short wire to the ground at the electrical service. With a large surge >the house ground can rise thousands of volts above absolute ground. You >want all wiring - power, phone, cable, satellite - to rise together. >This is stressed in the IEEE surge protection guide - very good >information. A cable entry ground block also has to connect with a short >wire - cable companies are not nearly as good as phone companies doing >this right. And satellite entry ground blocks also have to connect to >the power grounding system. Satellite installations can be even worse. > >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 $30 and might get a discounted price. This is a basic model.................. http://www.grainger.com/Grainger/items/1ECD1?Pid=search greg
From: GregS on 9 Jun 2010 15:05 In article <huon5i$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 always thought local surpressors were good to protect from motorized equipment and keep things common mode and to ground. 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. greg
From: Jeffrey D Angus on 9 Jun 2010 15:20 GregS wrote: > I just checked, and its difficult to find surpressors that > are cheap. I found one for $30 and might get a discounted > price. This is a basic model.................. > http://www.grainger.com/Grainger/items/1ECD1?Pid=search Well, you can't say inexpensive and Grainger in the same sentence. You'll find the exact same products elsewhere for 25-50% less. Jeff -- �Egotism is the anesthetic that dulls the pain of stupidity.� Frank Leahy, Head coach, Notre Dame 1941-1954 http://www.stay-connect.com
From: bud-- on 9 Jun 2010 17:04
GregS wrote: > In article <huon5i$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. 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. -- bud-- |