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DIY surge protection...
Awl --
On the main breaker box, for the whole house. First Q: Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? Holy ****..... Isn't surge protection just some capacitors?? Connected to where? Each hot to ground? Between hots? Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? And which wires go thru it? Hot? Hot+return? -- EA |
DIY surge protection...
On Mar 20, 8:47*am, "Existential Angst"
wrote: Awl -- On the main breaker box, for the whole house. First Q: *Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? * * * Holy ****..... Isn't surge protection just some capacitors?? *Connected to where? *Each hot to ground? Between hots? *Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? *And which wires go thru it? *Hot? *Hot+return? -- EA Surge protectors are not capacitors. They are made from material that will conduct electricity when the voltage exceeds some particular design value. That excess electric power is converted to heat in the surge protector. If the "surge" or spike is too long lasting or occurs so often that the surge protector does not have time to cool, it will eventually produce smoke and stop working. At that time any and all surges and spikes will continue on to the rest of your house. Usually the surge protector will die without you knowing about the death. There is no way to test them without a spike generator and an oscilloscope. The power spikes can come from anywhere. I personally experienced equipment destroying spikes that came from the telephone wires. A construction company was excavating very deeply for a sewer pumping station near my office. Somehow they connected 220 volts to the buried telephone cable. The power went through the local phone company junction box and into our phone system and fax machine. The surge protectors immediately absorbed all the power they could and produced smoke. Then the power continued on to burn out circuit boards in the equipment. We only discovered the source of the problem when a few days later I discovered a telephone guy installing a new junction box near our office. He told me about the construction company problem and how they were paying for the damage. They also paid us. So, bottom line is the protectors are probably a one-time only protection. There is no easy way to test. The surge may come from an unprotected source. This applies to all protectors, including all- house protectors. All lines coming to a house must be protected, Not just the "hot" lines. The "iron rings" you refer to are ferrite RF supressors. They reduce the electronic noise generated by switching power supplies. Paul |
DIY surge protection...
On Mar 20, 10:47*am, "Existential Angst"
wrote: Awl -- On the main breaker box, for the whole house. First Q: *Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? * * * Holy ****..... Isn't surge protection just some capacitors?? *Connected to where? *Each hot to ground? Between hots? *Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? *And which wires go thru it? *Hot? *Hot+return? -- EA They are not capacitors. They are electronic-semiconductor devices that are open circuit until some voltage threshold is exceeded, then they act like a very low resistance to try to limit the voltage. The limiting factor is the amount of power the devices can withstand before exploding due to the heat they generate when acting as s short circuit. I don't know a lot more than that, except that they are usually rated in Joules of energy they can dissipate before blowing up. They certainly cannot handle a direct strike to the power line, but induced voltage spikes due to nearby lightning can be handled if the joule rating is high enough. |
DIY surge protection...
In article ,
"Existential Angst" wrote: Awl -- On the main breaker box, for the whole house. First Q: Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? Holy ****..... I have a few whole-house (well, whole branch circuit) UL-rated surge arrestors. They are big (4" long by 2.25" diameter) plastic cans that attach to the main breaker box, and are wired into the branch circuits that they protect. The cans cost something like $50 each from the local electrical supply house, and are made by an outfit in Texas. I have a pair of their Model 302 arrestors. http://www.deltala.com/prod02.htm The website doesn't work right for Safari or Firefox in MacOS, so it's probably MSIE only. But you can make it work anyway, with fiddling and indirection. Isn't surge protection just some capacitors?? Connected to where? Each hot to ground? Between hots? Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. They are not just capacitors, they are industrial-size metal-oxide varistors plus capacitors. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? No. Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? And which wires go thru it? Hot? Hot+return? Probably ferrite EMI-supression "beads", which have no effect on computer-smoking surges. Yes, it's hot+return. Joe Gwinn |
DIY surge protection...
Existential Angst wrote:
So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. A little more dramatic/intrusive in its action than surge protector, in that power is removed, but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
DIY surge protection...
"cavelamb" wrote in message
m... Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. A little more dramatic/intrusive in its action than surge protector, in that power is removed, but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. What do fast-acting UPS's use? Use the same thing? Mebbe solid state relays? They're proly cheaper than mechanicals, by now, and I would assume pretty fast. There's an A/C supply outfit that sells, iirc, a 2 pole 50 A jobby for under $20. The neat thing is, the "coil" is good for, like, 100-300 V!!! -- EA -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
DIY surge protection...
Paul sez::
""The power spikes can come from anywhere. I personally experienced equipment destroying spikes that came from the telephone wires. ASo, bottom line is the protectors are probably a one-time only protection. There is no easy way to test. The surge may come from an unprotected source. This applies to all protectors, including all- house protectors. All lines coming to a house must be protected, Not just the "hot" lines."" Yep! Call them, "Fail dead and burned open" with usu. no visible way of determining when failure occurrs. Yeah, I know some have a pilot light but it is easy to ignore. Bob Swinney |
DIY surge protection...
Existential Angst wrote:
"cavelamb" wrote in message m... Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. A little more dramatic/intrusive in its action than surge protector, in that power is removed, but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. What do fast-acting UPS's use? Use the same thing? Mebbe solid state relays? MOVs = Metal Oxide Varisters They're proly cheaper than mechanicals, by now, and I would assume pretty fast. There's an A/C supply outfit that sells, iirc, a 2 pole 50 A jobby for under $20. The neat thing is, the "coil" is good for, like, 100-300 V!!! Spikes can go WAY bigger than a paltry 300 v And the unsuppressed arc across a relay contact - 30KV? -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
DIY surge protection...
On Mar 20, 10:31*am, "Existential Angst"
wrote: "cavelamb" wrote in message m... Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. *Proly a NO relay. A little more dramatic/intrusive *in its action than surge protector, in that power is removed, *but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. *Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. What do fast-acting UPS's use? *Use the same thing? *Mebbe solid state relays? They're proly cheaper than mechanicals, by now, and I would assume pretty fast. There's an A/C supply outfit that sells, iirc, a 2 pole 50 A jobby for under $20. *The neat thing is, the "coil" is good for, like, 100-300 V!!! -- EA -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ You were probably still a baby when the whole thing about power protection got started. There was a HUGE argument between marketing people and engineers relating to "UPS". Marketing called them uninterruptable power sources (UPS) and engineers demanded they be called Stand-By power sources(SPS). All the things you buy today are really stand-by power sources. They have a real mechanical relay that switches from the power line to battery source. A real UPS will cost many hundreds to many thousands of dollars. They continually supply power from batteries and the AC just keeps the batteries charged. An electronic circuit keeps the internally generated AC synchronized to the external power frequency. The marketing people finally won the battle. Guess it was the money, not the truth. All computers and associated equipment, today, used switching power supplies which can continue to operate during the 2-4 cycles it takes the mechanical relay to switch and the time to start the electronics to begin supplying AC power. Paul |
DIY surge protection...
On Mar 20, 1:27*pm, cavelamb wrote:
Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. *Proly a NO relay. ......... If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. *Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. Richard Lambhttp://www.home.earthlink.net/~cavelamb/ http://en.wikipedia.org/wiki/Varistor Note the microseconds. Relays take thousands of microseconds to operate. Here's a traditional answer: http://www.solahd.com/products/power...ioning/cvs.htm TV repairmen used them to make hot-chassis sets safer to work on. I have one but use a UPS instead. jsw |
DIY surge protection...
wrote:
You talkin' to ME, kid??? You were probably still a baby when the whole thing about power protection got started. There was a HUGE argument between marketing people and engineers relating to "UPS". Marketing called them uninterruptable power sources (UPS) and engineers demanded they be called Stand-By power sources(SPS). All the things you buy today are really stand-by power sources. They have a real mechanical relay that switches from the power line to battery source. A real UPS will cost many hundreds to many thousands of dollars. They continually supply power from batteries and the AC just keeps the batteries charged. An electronic circuit keeps the internally generated AC synchronized to the external power frequency. The marketing people finally won the battle. Guess it was the money, not the truth. All computers and associated equipment, today, used switching power supplies which can continue to operate during the 2-4 cycles it takes the mechanical relay to switch and the time to start the electronics to begin supplying AC power. Paul -- Richard Lamb http://www.home.earthlink.net/~cavelamb/ |
DIY surge protection...
Existential Angst wrote:
Awl -- On the main breaker box, for the whole house. First Q: Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? Holy ****..... Isn't surge protection just some capacitors?? Connected to where? Each hot to ground? Between hots? Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? And which wires go thru it? Hot? Hot+return? Hi, Whoa! At last EA is showing his true intelligence exposing his level of ignorance. 'nuff said. |
DIY surge protection...
Paul sez:
"There was a HUGE argument between marketing people and engineers relating to "UPS". Marketing called them uninterruptable power sources (UPS) and engineers demanded they be called Stand-By power sources(SPS). All the things you buy today are really stand-by power sources. They have a real mechanical relay that switches from the power line to battery source. A real UPS will cost many hundreds to many thousands of dollars. They continually supply power from batteries and the AC just keeps the batteries charged. An electronic circuit keeps the internally generated AC synchronized to the external power frequency. The marketing people finally won the battle. Guess it was the money, not the truth." One very knowledgeable cohort of mine used to speak of them as real UPS's and "chicken UPS's" During that time, I was project manager on a couple of large UPS installations, both on PBX plants. One was a 4000 line PBX and the other was 2000 line. They were Lorraine Electric units, uninterruptible in every sense of the word, with huge lead-acid batterys. As I recall the batts in the 4000 line unit were sized for nominally 24 hours. Bob Swinney |
DIY surge protection...
Robert Swinney wrote:
Paul sez: "There was a HUGE argument between marketing people and engineers relating to "UPS". Marketing called them uninterruptable power sources (UPS) and engineers demanded they be called Stand-By power sources(SPS). All the things you buy today are really stand-by power sources. They have a real mechanical relay that switches from the power line to battery source. A real UPS will cost many hundreds to many thousands of dollars. They continually supply power from batteries and the AC just keeps the batteries charged. An electronic circuit keeps the internally generated AC synchronized to the external power frequency. The marketing people finally won the battle. Guess it was the money, not the truth." One very knowledgeable cohort of mine used to speak of them as real UPS's and "chicken UPS's" During that time, I was project manager on a couple of large UPS installations, both on PBX plants. One was a 4000 line PBX and the other was 2000 line. They were Lorraine Electric units, uninterruptible in every sense of the word, with huge lead-acid batterys. As I recall the batts in the 4000 line unit were sized for nominally 24 hours. Bob Swinney Hi, In my working days in radio telcomm. UPS was composed of battery bank, motor-generator set and control(switching) unit. I don't recall we ever suffered radio link outage. This is true UPS. |
DIY surge protection...
On Sat, 20 Mar 2010 11:47:51 -0400, "Existential Angst"
wrote: Awl -- On the main breaker box, for the whole house. First Q: Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? Holy ****..... Isn't surge protection just some capacitors?? Connected to where? Each hot to ground? Between hots? Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? And which wires go thru it? Hot? Hot+return? Here's a very good document on home protection written for the non-electrically inclined- http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf Pay particular attention to the section on GPR, there's a lot of people in the industry who, while they may know about it "intellectually", don't really think about it enough. :( Suppressors don't just protect against lightening but also against transient spikes on the power lines induced by heavy equipment etc. How much protection you get depends on how much money you spend. The cheaper MOV "little black box" units that Mr. Holme's electrician is so in love with (he does do neat wiring, though :)) are good for the occasional spike, if you live in an area prone to lightening & you own a lot of $$$ electronics you might want fork out for an industrial strength unit- http://www.transtector.com/ProductData?class=acph but figure on ~$1000 for a top of the line one with SASD devices that will stand up to the abuse. H.. |
DIY surge protection...
cavelamb wrote in
m: Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. A little more dramatic/intrusive in its action than surge protector, in that power is removed, but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. often,the "protected" parts are faster to blow than the protection device. there are specs on how fast such protection has to operate. It's a few nanoseconds. also,how much energy)in joules) that it must be able to shunt or absorb. Often,the strike is way more than the device can tolerate. I've seen MOVs that has absorbed a lightning strike and blew apart,yet the power supply itself survived.All it needed was a new fuse and cleaning the blown MOV's metal deposits off the PCB. -- Jim Yanik jyanik at localnet dot com |
DIY surge protection...
cavelamb wrote in
: Existential Angst wrote: "cavelamb" wrote in message m... Existential Angst wrote: So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. A little more dramatic/intrusive in its action than surge protector, in that power is removed, but it should do the job, protection-wise. AND this would have the advantage of being re-usable essentially forever, and also testable. If you wanted to get fancy, you could have this coordinated with a UPS and generator, so that no perceptible power interruption occurs. Much more $$, of course. Relays are mechanical devices and, as such, operate in slo-mo compared to electricity. What do fast-acting UPS's use? Use the same thing? Mebbe solid state relays? MOVs = Metal Oxide Varisters also Transzorbs,gas discharge tubes,in-series inductors to slow down the strike's rise-time,even back-to-back zeners(not good). They're proly cheaper than mechanicals, WAY cheaper. Most of your commercial surge protectors use them,along with a fast blow fuse and maybe a line filter if you're lucky. DAGS. -- Jim Yanik jyanik at localnet dot com |
DIY surge protection...
No, it isn't. A "true" GPS, be it motor-gen or otherwise, is not the genuine animal unless it's
output is being generated constantly whether commercial power is present or not. A motor-gen UPS would not be fit the true GPS definition unless the generator ran constantly from its source of power, battery or commercial. In the "true" GPS, switching is implemented only in the event of primary power failure; and then only to interrupt or restore primary power to the batteries charging component. Bob Swinney "Tony Hwang" wrote in message ... Robert Swinney wrote: Paul sez: "There was a HUGE argument between marketing people and engineers relating to "UPS". Marketing called them uninterruptable power sources (UPS) and engineers demanded they be called Stand-By power sources(SPS). All the things you buy today are really stand-by power sources. They have a real mechanical relay that switches from the power line to battery source. A real UPS will cost many hundreds to many thousands of dollars. They continually supply power from batteries and the AC just keeps the batteries charged. An electronic circuit keeps the internally generated AC synchronized to the external power frequency. The marketing people finally won the battle. Guess it was the money, not the truth." One very knowledgeable cohort of mine used to speak of them as real UPS's and "chicken UPS's" During that time, I was project manager on a couple of large UPS installations, both on PBX plants. One was a 4000 line PBX and the other was 2000 line. They were Lorraine Electric units, uninterruptible in every sense of the word, with huge lead-acid batterys. As I recall the batts in the 4000 line unit were sized for nominally 24 hours. Bob Swinney Hi, In my working days in radio telcomm. UPS was composed of battery bank, motor-generator set and control(switching) unit. I don't recall we ever suffered radio link outage. This is true UPS. |
DIY surge protection...
On Mar 20, 12:26 pm, "hr(bob) "
wrote: They are not capacitors. They are electronic-semiconductor devices that are open circuit until some voltage threshold is exceeded, then they act like a very low resistance to try to limit the voltage. The limiting factor is the amount of power the devices can withstand before exploding due to the heat they generate when acting as s short circuit. I don't know a lot more than that, except that they are usually rated in Joules of energy they can dissipate before blowing up. Either you buy a protector that will somehow absorb all that energy. Or you buy protectors based upon how it was done even 100 years ago. Protection is always about where energy dissipated. Either that energy remains outside the building. Or that energy is inside hunting for earth ground destructively via appliances. Adjacent protectors simply give surges even more potentially destructive paths through adjacent appliances. An effective surge protector means even the protector remains functional. A minimal 'whole house' protector starts at 50,000 amps. Direct lightning strikes are typically 20,000 amps. Yes, the protector must be sized to even earth direct lightning strikes and remain functional. And that means the connection to earth must be additional requirements - short ('less than 10 feet) to earth, no sharp wire bends, no splices. all protectors meet at (again 'less than 10 feet to') the single point earth ground, ground wires separated from other non-ground wires, not inside metallic conduit, etc. Protection is always about where energy dissipates. If those hundreds of thousands of joules dissipate in earth, then no damage. This is how it was done even 100 years ago. But somehow a magic box next to the appliance will absorb all those joules? Always view the tech specs. Plug-in protectors rates at hundreds of joules will somehow make hundreds of thousands just disappear? That is what they claim. In analysis, we even traced surges earthed destructive through a network of powered off computers because the surge was permitted inside the building. And because a surge on the black (hot) wire was connected directly to the motherboard by the protector. The protector bypassed protection inside the computer's power supply. Telcos do not waste money on protectors adjacent to electronics. That switching center must never suffer damage. A switching center, connected to overhead wires all over town, may suffer 100 surges with each thunderstorm - and no damage. Why? Each protector connects short to the single point earth ground. And the protector is up to 50 meters separated from electronics. That separation increases protection. No protector is protection. None. The only effective protectors make that short connection to single point earth ground. Ineffective protectors (a $3 power strip with some ten cent protector parts selling for $25 or $150) are profit centers. The NIST (US government research agency) discusses those ineffective protectors by describing what every protector must do: A very important point to keep in mind is that your surge protector will work by diverting the surges to ground. The best surge protection in the world can be useless if grounding is not done properly. The NIST describes plug-in protectors as "useless". Obviously. It does not even claim protection in its numeric specs. Find those spec numbers that list each type of surge and protection from that surge? No plug-in protector makes protection claims. They are a profit center. Protection is always about where energy dissipates. IOW why facilities with effective protection both meet and exceed post 1990 National Electrical code. Where does energy dissipate? A protector is only as effective as its earth ground - which no plug-in protector has and therefore will not discuss. Effective 'whole house' protectors come from General Electric, Keison, Intermatic, Siemens, Square D, and Leviton. An effective Cutler-Hammer solution sells in Lowes and Home Depot for less than $50. |
DIY surge protection...
On Sat, 20 Mar 2010 11:47:51 -0400, "Existential Angst"
wrote: First Q: Is surge protection strictly lightning-related? A surge protecter/surge suppressor is one thing. http://en.wikipedia.org/wiki/Surge_protector http://www.elect-spec.com/faqspike.htm Spikes might be another. Beware induced spikes on phone & data lines. -- Cliff |
DIY surge protection...
On Sat, 20 Mar 2010 15:27:58 -0500, "Robert Swinney" wrote:
One very knowledgeable cohort of mine used to speak of them as real UPS's and "chicken UPS's" During that time, I was project manager on a couple of large UPS installations, both on PBX plants. One was a 4000 line PBX and the other was 2000 line. They were Lorraine Electric units, uninterruptible in every sense of the word, with huge lead-acid batterys. As I recall the batts in the 4000 line unit were sized for nominally 24 hours. The land-line phones usually work. 40 VDC IIRC. -- Cliff |
DIY surge protection...
On Mar 20, 7:09*pm, westom wrote:
On Mar 20, 12:26 pm, "hr(bob) " wrote: They are not capacitors. *They are electronic-semiconductor devices that are open circuit until some voltage threshold is exceeded, then they act like a very low resistance to try to limit the voltage. *The limiting factor is the amount of power the devices can withstand before exploding due to the heat they generate when acting as s short circuit. *I don't know a lot more than that, except that they are usually rated in Joules of energy they can dissipate before blowing up. * Either you buy a protector that will somehow absorb all that energy. *Or you buy protectors based upon how it was done even 100 years ago. *Protection is always about where energy dissipated. Either that energy remains outside the building. *Or that energy is inside hunting for earth ground destructively via appliances. Adjacent protectors simply give surges even more potentially destructive paths through adjacent appliances. * An effective surge protector means even the protector remains functional. *A minimal 'whole house' protector starts at 50,000 amps. Direct lightning strikes are typically 20,000 amps. *Yes, the protector must be sized to even earth direct lightning strikes and remain functional. *And that means the connection to earth must be additional requirements - short ('less than 10 feet) to earth, no sharp wire bends, no splices. all protectors meet at (again 'less than 10 feet to') the single point earth ground, ground wires separated from other non-ground wires, not inside metallic conduit, etc. * Protection is always about where energy dissipates. *If those hundreds of thousands of joules dissipate in earth, then no damage. This is how it was done even 100 years ago. * But somehow a magic box next to the appliance will absorb all those joules? *Always view the tech specs. *Plug-in protectors rates at hundreds of joules will somehow make hundreds of thousands just disappear? *That is what they claim. *In analysis, we even traced surges earthed destructive through a network of powered off computers because the surge was permitted inside the building. *And because a surge on the black (hot) wire was connected directly to the motherboard by the protector. *The protector bypassed protection inside the computer's power supply. * Telcos do not waste money on protectors adjacent to electronics. That switching center must never suffer damage. *A switching center, connected to overhead wires all over town, may suffer 100 surges with each thunderstorm - and no damage. *Why? *Each protector connects short to the single point earth ground. *And the protector is up to 50 meters separated from electronics. *That separation increases protection. * No protector is protection. *None. *The only effective protectors make that short connection to single point earth ground. *Ineffective protectors (a $3 power strip with some ten cent protector parts selling for $25 or $150) are profit centers. *The NIST (US government research agency) discusses those ineffective protectors by describing what every protector must do: A very important point to keep in mind is that your *surge protector will work by diverting the surges to *ground. *The best surge protection in the world can *be useless if grounding is not done properly. * The NIST describes plug-in protectors as "useless". *Obviously. *It does not even claim protection in its numeric specs. *Find those spec numbers that list each type of surge and protection from that surge? No plug-in protector makes protection claims. *They are a profit center. * Protection is always about where energy dissipates. *IOW why facilities with effective protection both meet and exceed post 1990 National Electrical code. *Where does energy dissipate? *A protector is only as effective as its earth ground - which no plug-in protector has and therefore will not discuss. Effective 'whole house' protectors come from General Electric, Keison, Intermatic, Siemens, Square D, and Leviton. *An effective Cutler-Hammer solution sells in Lowes and Home Depot for less than $50. How bout a surge from downed power lines? Ours got knocked down from ice on trees falling on the main lines into the house 4am Christmas eve. Started a fire (12" flames) on the Belkin UL approved spike/ surge protector right next to the christmas tree & plasma TV! Could never get an answer as to why this happened. Knocked out a couple other surge strips including a plug in CO2 detector. Thank god thats all that happened. http://users.cin.net/~milgil/Belkin_burned1.JPG http://users.cin.net/~milgil/Belkin_burned2.JPG http://users.cin.net/~milgil/Belkin_burned3.JPG http://users.cin.net/~milgil/Belkin_burned4.JPG http://users.cin.net/~milgil/Belkin_burned5.JPG Must be something to do with the end of the power- where it dissipates ? -- BB;s #9 The older you get The more you suspect Ideas long set Are just all wet ©¿© ~gil~ |
DIY surge protection...
On Mar 20, 12:22*pm, " wrote:
On Mar 20, 8:47*am, "Existential Angst" wrote: Awl -- On the main breaker box, for the whole house. First Q: *Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? * * * Holy ****..... Isn't surge protection just some capacitors?? *Connected to where? *Each hot to ground? Between hots? *Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? *And which wires go thru it? *Hot? *Hot+return? -- EA Surge protectors are not capacitors. They are made from material that will conduct electricity when the voltage exceeds some particular design value. That excess electric power is converted to heat in the surge protector. That isn't correct. The main function of a surge protector is to shunt the current to ground. In doing so, SOME of the power is converted to heat as it passes through because the MOVs are not perfect conductors and do have some small resistance. If the "surge" or spike is too long lasting or occurs so often that the surge protector does not have time to cool, it will eventually produce smoke and stop working. At that time any and all surges and spikes will continue on to the rest of your house. Usually the surge protector will die without you knowing about the death. There is no way to test them without a spike generator and an oscilloscope. All of the good whole house surge protectors that I have seen have indicator lights that show if they are still functioning or not. Some also have audible alarms to signal that they have failed, or relay contacts that can be sent to a remote alarm system, etc. The power spikes can come from anywhere. I personally experienced equipment destroying spikes that came from the telephone wires. A construction company was excavating very deeply for a sewer pumping station near my office. Somehow they connected 220 volts to the buried telephone cable. The power went through the local phone company junction box and into our phone system and fax machine. The surge protectors immediately absorbed all the power they could and produced smoke. Then the power continued on to burn out circuit boards in the equipment. We only discovered the source of the problem when a few days later I discovered a telephone guy installing a new junction box near our office. He told me about the construction company problem and how they were paying for the damage. They also paid us. So, bottom line is the protectors are probably a one-time only protection. There is no easy way to test. The surge may come from an unprotected source. This applies to all protectors, including all- house protectors. All lines coming to a house must be protected, Not just the "hot" lines. The "iron rings" you refer to are ferrite RF supressors. They reduce the electronic noise generated by switching power supplies. Paul- Hide quoted text - - Show quoted text - |
DIY surge protection...
On Mar 20, 9:09*pm, westom wrote:
On Mar 20, 12:26 pm, "hr(bob) " wrote: They are not capacitors. *They are electronic-semiconductor devices that are open circuit until some voltage threshold is exceeded, then they act like a very low resistance to try to limit the voltage. *The limiting factor is the amount of power the devices can withstand before exploding due to the heat they generate when acting as s short circuit. *I don't know a lot more than that, except that they are usually rated in Joules of energy they can dissipate before blowing up. Well, we all knew this was coming. Mention surge protector, and like a bolt of lightning from the sky, here comes WTom. * Either you buy a protector that will somehow absorb all that energy. *Or you buy protectors based upon how it was done even 100 years ago. *Protection is always about where energy dissipated. Either that energy remains outside the building. *Or that energy is inside hunting for earth ground destructively via appliances. Adjacent protectors simply give surges even more potentially destructive paths through adjacent appliances. * An effective surge protector means even the protector remains functional. *A minimal 'whole house' protector starts at 50,000 amps. Direct lightning strikes are typically 20,000 amps. *Yes, the protector must be sized to even earth direct lightning strikes and remain functional. *And that means the connection to earth must be additional requirements - short ('less than 10 feet) to earth, no sharp wire bends, no splices. all protectors meet at (again 'less than 10 feet to') the single point earth ground, ground wires separated from other non-ground wires, not inside metallic conduit, etc. * Protection is always about where energy dissipates. *If those hundreds of thousands of joules dissipate in earth, then no damage. This is how it was done even 100 years ago. So far, I would mostly agree. Except the part about a direct lightning strike. A direct lightning strike is mostly a red herring, because even if the lightning bolt hit the service cable near the building, it's highly unlikely that the path of all or even most of the lightning is going to be through the service wire and into the surge protector. Far more likely, it will arc with most of the energy finding ground outside the building before it ever gets to the surge protector at the panel or meter. * But somehow a magic box next to the appliance will absorb all those joules? Here;s where Tom likes to start arguing against strawmans and the rant about plug-in surge protectors begins. The actual question was about a whole house surge protector. *Always view the tech specs. *Plug-in protectors rates at hundreds of joules will somehow make hundreds of thousands just disappear? *That is what they claim. *In analysis, we even traced surges earthed destructive through a network of powered off computers because the surge was permitted inside the building. *And because a surge on the black (hot) wire was connected directly to the motherboard by the protector. *The protector bypassed protection inside the computer's power supply. * Telcos do not waste money on protectors adjacent to electronics. Total nonsense. Every line card on a telco switch has surge protection right on the card where it connects to the incoming line. Much like if you take apart an analog modem, you will almost always find MOVs or similar components there. That switching center must never suffer damage. *A switching center, connected to overhead wires all over town, may suffer 100 surges with each thunderstorm - and no damage. *Why? *Each protector connects short to the single point earth ground. *And the protector is up to 50 meters separated from electronics. *That separation increases protection. In fact, just like the IEEE recommends, the telco uses a tiered approach. Yes, they have surge protection where the line enters the building. But they also have it on the line cards. Months ago I even found you semiconductors designed and marketed for telcos that go on the linecards, complete with the application notes. Yet, here we go again. * No protector is protection. *None. *The only effective protectors make that short connection to single point earth ground. *Ineffective protectors (a $3 power strip with some ten cent protector parts selling for $25 or $150) are profit centers. *The NIST (US government research agency) discusses those ineffective protectors by describing what every protector must do: Please provide us a link to NIST or any other credible source that says plug-in protectors are ineffective as part of a protection plan. You've been asked that here for years and we have yet to see the link. A very important point to keep in mind is that your *surge protector will work by diverting the surges to *ground. *The best surge protection in the world can *be useless if grounding is not done properly. * The NIST describes plug-in protectors as "useless". *Obviously. *It does not even claim protection in its numeric specs. *Find those spec numbers that list each type of surge and protection from that surge? No plug-in protector makes protection claims. *They are a profit center. * Protection is always about where energy dissipates. *IOW why facilities with effective protection both meet and exceed post 1990 National Electrical code. *Where does energy dissipate? *A protector is only as effective as its earth ground - which no plug-in protector has and therefore will not discuss. Effective 'whole house' protectors come from General Electric, Keison, Intermatic, Siemens, Square D, and Leviton. *An effective Cutler-Hammer solution sells in Lowes and Home Depot for less than $50. And here comes the list again. What Tom won't tell you is that of those companies on his list of real effective and responsible manufacturers, most of them also sell plug-in surge protectors. They recommend using them as part of a tiered strategy. As for the HD solution for less than $50, that doesn't square with your criteria of needing a minimum of 50,000 amps, because they have no such product available at HD. The best advice was already provided. That was the link to the IEEE guide on surge protection. http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf Everyone can read what respected peer-reviewed engineers recommend. And I can tell you this. They don't say plug-ins are ineffective. Read chapters 5 and 6. Instead, they show them being used as part of a tiered strategy. You put whole house protection at the meter or panel. Then you use plug-ins that route all power and signal through them, to further protect key equipment, eg, TVs, PCs, etc. |
DIY surge protection...
On Mar 20, 9:47*am, "Existential Angst"
wrote: Awl -- On the main breaker box, for the whole house. First Q: *Is surge protection strictly lightning-related? Holmes on Homes was emphasizing this, saying $500 wasn't much for the protection it affords. $500?????????????? * * * Holy ****..... Isn't surge protection just some capacitors?? *Connected to where? *Each hot to ground? Between hots? *Values? I have a ton of run/start caps, 20 to 100 uF, 370 V. If you have surge protection on the mains, do you then need those itty-bitty surge protectors fer yer pyooters? Also, sometimes equipment will have an iron-like ring around a wire -- I think in power supplies, mebbe surge protectors. What is that ring doing? *And which wires go thru it? *Hot? *Hot+return? -- EA Ferrite rings are for EMI, so the buzz in the box stays there and not in your radio or stereo. Switching power supplies can generate a whole lot of hash and that's the type that's gradually replacing the old-syle wall warts. The ring is acting as a choke for RF, also generated by the computer itself. Different deal than surge protection, but also needed these days. Look up "surgistor" or MOV, that's what's in those surge protectors. They're rated in joules, the amount of energy they can pass. The higher, the better, and more costly they get. The better surge protector strips will say how much energy they can handle on the package. I assume the panel versions do the same. What none of the ad copy says is that MOVs have a distinct lifespan. They WILL wear out after snubbing "x" number of spikes and become useless. Some of the power strip units tie the neon switch light to the MOVs. If no light when switched on, the MOVs have expired and it's time for a new strip. But nobody tells the consumer about it. So there's a whole lot of dead protectors out there that are just power strips now. Usually there's MOVs between ground and each supply wire and between the supply wires. Not rocket science. As far as lightning protection, they'll do part of that, up to the energy rating. Which is why you need the tiered approach. Arrestors on the line in, surge protectors on the panel and on each high-value electronic item. My sister is always getting hits, they blow the phones off the walls, but since she's gotten decent surge protectors, those get fried instead of the computer or video equipment. They have to be replaced, but she gets the sort with insurance attached, so not that costly. There are other approaches to surge and spike protection, an MG set is pretty much immune to any such up to direct lightning strikes. A ferro-resonant transformer used to be a big part of the innards of one line of power conditioners, pretty much immune to spikes, but the transformer itself was noisier than a whole switch yard. Had one in a corner of the shop for a mini-computer, had to go outside to talk to anyone. None of those will snub spikes on LAN, phone or video cables, for that you have to go to power strips with built-in protection or stand-alones. Stan |
DIY surge protection...
Jim Yanik wrote:
What do fast-acting UPS's use? Use the same thing? Mebbe solid state relays? MOVs = Metal Oxide Varisters also Transzorbs,gas discharge tubes,in-series inductors to slow down the strike's rise-time,even back-to-back zeners(not good). Can Gas discharge tubes be wired in series to increase the trigger voltage. I have a bunch of 70V ones I could use in my panel if so. |
DIY surge protection...
cncmillgil wrote:
How bout a surge from downed power lines? Ours got knocked down from ice on trees falling on the main lines into the house 4am Christmas eve. Started a fire (12" flames) on the Belkin UL approved spike/ surge protector right next to the christmas tree & plasma TV! Could never get an answer as to why this happened. Knocked out a couple other surge strips including a plug in CO2 detector. Thank god thats all that happened. http://users.cin.net/~milgil/Belkin_burned1.JPG http://users.cin.net/~milgil/Belkin_burned2.JPG http://users.cin.net/~milgil/Belkin_burned3.JPG http://users.cin.net/~milgil/Belkin_burned4.JPG http://users.cin.net/~milgil/Belkin_burned5.JPG Must be something to do with the end of the power- where it dissipates ? Looks like a pretty good case for metal enclosed surge protectors. |
DIY surge protection...
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DIY surge protection...
Cliff wrote:
On Sat, 20 Mar 2010 15:27:58 -0500, "Robert Swinney" wrote: One very knowledgeable cohort of mine used to speak of them as real UPS's and "chicken UPS's" During that time, I was project manager on a couple of large UPS installations, both on PBX plants. One was a 4000 line PBX and the other was 2000 line. They were Lorraine Electric units, uninterruptible in every sense of the word, with huge lead-acid batterys. As I recall the batts in the 4000 line unit were sized for nominally 24 hours. The land-line phones usually work. 40 VDC IIRC. 48 volts DC standard at the central office. I've seen all sorts of variations on POTS lines but the standard is 48 VDC. TDD |
DIY surge protection...
On Sun, 21 Mar 2010 04:05:11 -0700 (PDT), cncmillgil wrote:
Could never get an answer as to why this happened. Knocked out a couple other surge strips including a plug in CO2 detector. While I was staying in a motel in Southington, CT an empty room burned. Smoke detector started the fire. Melted & dripped flaming plastic on the bed .... (Had central wiring back to the office & was poorly installed.) -- Cliff |
DIY surge protection...
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DIY surge protection...
westom wrote:
An effective surge protector means even the protector remains functional. A minimal 'whole house' protector starts at 50,000 amps. Direct lightning strikes are typically 20,000 amps. Yes, the protector must be sized to even earth direct lightning strikes and remain functional. Lightning strikes can be far larger than 50,000A (but low percentage). But a strike to a power line has multiple paths to earth. Investigations have shown the largest lightning-caused surge with any reasonable probability of occurring is 10,000A on an incoming power wire. The 50,000A suppressor rating can handle that. High ratings give long life. The best information on surges and surge protection is in a guide from the IEEE at: http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf (also posted by Howard and trader) and a simpler guide from the NIST at: http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf Neither service panel or plug-in suppressors can reliably handle crossed power lines. MOVs which can handle 10,000A for maybe 100 microseconds are rapidly burned out by longer duration events. (These events are probably the major cause of catastrophic MOV failures.) I would not make my own suppressor attached to power lines (other than fuse protected MOVs in equipment). But somehow a magic box next to the appliance will absorb all those joules? Always view the tech specs. Plug-in protectors rates at hundreds of joules will somehow make hundreds of thousands just disappear? Poor w has to warp a thread about service panel suppressors to his favorite topic - plug-in suppressors. Trying to not repeat traders nice reply.... François Martzloff was the surge guru at the NIST and wrote the NIST guide. He also wrote numerous published technical papers. One paper looked at the energy absorbed in a MOV on a branch circuit. It was surprisingly small - 35 Joules max. In 13 of 15 cases it was 1 Joule or less. That was with up to 10,000A coming in on the service wire. There are a couple of reasons for that - I could elaborate if anyone is interested. Plug-in suppressors are only a "magic box" to w because he refuses to understand how they work - clearly explained in the IEEE guide starting pdf page 40. They work by CLAMPING (limiting) the voltage on all wires (signal and power) to the common ground at the suppressor. Plug-in suppressors do not work primarily by earthing (or absorbing). The guide explains earthing occurs elsewhere. According to NIST guide, US insurance information indicates equipment most frequently damaged by lightning is computers with a modem connection TVs, VCRs and similar equipment (presumably with cable TV connections). It is likely that much of equipment damage is from high voltages between power and signal wires. This is illustrated in the IEEE guide example starting pdf page 40. A service panel suppressor can not limit the voltage between power and signal wires. To do that, there has to be a *short* ground wire from the telephone entrance protector to the earthing system near the power service. Also for the cable entrance ground block (and dish....) With a large surge current to earth, the "ground" at the building can rise thousands of volts above "absolute ground". Much of the protection is that power and phone and cable wires rise together. If short ground wires can not be used (as in the IEEE guide example) the guide says "the only effective way of protecting the equipment is to use a multiport [plug-in] protector." For similar reasons, all protected equipment that is interconnected needs to be connected to the same plug-in suppressor. External connections, like phone, also need to go through the suppressor. Connecting all wiring through the suppressor prevents damaging voltages between power and signal wires. The NIST describes plug-in protectors as "useless". What does the NIST guide really say about plug-in suppressors? They are "the easiest solution". And "one effective solution is to have the consumer install" a multiport plug-in suppressor. A protector is only as effective as its earth ground The required statement of religious belief in earthing. Why aren't airplanes crashing daily when they get hit by lightning (or do they drag an earthing chain)? Often asked and never answered - simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why does the NIST guide say "One effective solution is to have the consumer install" a multiport plug-in suppressor? - Why does the IEEE guide say for distant service points "the only effective way of protecting the equipment is to use a multiport [plug-in] protector"? - Why do your favorite manufacturers make plug-in suppressors? - Why does favorite manufacturer SquareD say (for their service panel suppressor) "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use"? And why can't you find a source that agrees with you that plug-in suppressors are not effective? For real science read the IEEE and NIST guides . Both say plug-in suppressors are effective. -- bud-- |
DIY surge protection...
wrote:
On Sat, 20 Mar 2010 10:57:42 -0700 (PDT), Jim Wilkins Here's a traditional answer: http://www.solahd.com/products/power...ioning/cvs.htm TV repairmen used them to make hot-chassis sets safer to work on. I have one but use a UPS instead. jsw What you need to make working on a hot chassis safer is an isolation transformer. Many power conditioners use one, but electronic service technicians usually use a Variac, which is an isolation transformer that has a variable output control. Useful for "bringing up" voltage gradually for various purposes, in addition to the safety it provides. http://variac.com/ or as an alternative: http://www.fotronic.com/bk-precision...lies/1653a.htm The Variac is available with higher current capability than the B&K, so it is preferred by people who work on big TV's and commercial sound reinforcement. All Variacs I have seen are transformer (or autotransformer) windings on a toroid core with the windings available to a brush that sweeps around. They provide nice variable voltage but no isolation. -- bud-- |
DIY surge protection...
I have designed EMP protection for missile silos.
I have designed lightning protection for aircraft. I have designed surge protection for aircraft. I have not designed surge protection for households. But once in a start up, I was testing the upper limit of the input Voltage range for the switching powers supply I had designed for an ultrasound cart. I used a surge protector power strip as an extension chord. I dialed up up the 60Hz AC to a couple hundred VAC. If the surge protector worked for a while, I don't know. But the stink of the smoke that came out of that surge protector had to be smelled to be believed. |
DIY surge protection...
On Mar 22, 11:28*am, "
wrote: *I have designed EMP protection for missile silos. I have designed lightning protection for aircraft. I have designed surge protection for aircraft. I have not designed surge protection for households. But once in a start up, I was testing the upper limit of the input Voltage range for the switching powers supply I had designed for an ultrasound cart. I used a surge protector power strip as an extension chord. I dialed up up the 60Hz AC to a couple hundred VAC. If the surge protector worked for a while, I don't know. But the stink of the smoke that came out of that surge protector had to be smelled to be believed. You needed a protector with larger smoke packets. Yours ran out too soon! Paul |
DIY surge protection...
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DIY surge protection...
Existential Angst wrote:
So the surge protector is a kind of crude voltage regulator? Well, how about this: Why not put a 100 A relay in the service, with the coil connected to a fast-acting voltage-sensing amplifier. If the voltage goes up by more than, say, 10%, the relay is activated (or deactivated, if NO), all power to the house is broken, with the relay latching out, requiring a manual re-start. Proly a NO relay. The standard protectors are tested against is the so-called 8/20 surge, the 8 means an 8 MICROSECOND rise time. So, the current rises to it's peak value in 8 us, then decays in 20 us after that. Relays take many milliseconds to react, and a lightning surge will just jump right over the open contacts, anyway. So, totally FORGET anything using relays. Jon |
DIY surge protection...
Existential Angst wrote:
What do fast-acting UPS's use? Use the same thing? Mebbe solid state relays? SSR's generally use SCR's, which have the property that they don't turn off until the current is interrupted. Normal 60 Hz power turns off 120 times a second. But, when you tell the thing to turn off during a surge, it will totally ignore the command because the current is still flowing. Really high-end UPS's do use fancy devices like back-to-back giant IGBT's, but most probably just use an electro-mechanical relay, and are designed to supplement dropped line power, not protect the load. There are "on line" UPS's that only use electromechanical relays to bypass a failed inverter, and otherwise all connection from input to output is through the DC battery bank. These are usually pretty expensive (thousands of $ for a small one) noisy and waste a lot of power, too. Jon |
DIY surge protection...
On Mon, 22 Mar 2010 17:33:25 -0500, Jon Elson
wrote: wrote: The power spikes can come from anywhere. I personally experienced equipment destroying spikes that came from the telephone wires. A construction company was excavating very deeply for a sewer pumping station near my office. Somehow they connected 220 volts to the buried telephone cable. The power went through the local phone company junction box and into our phone system and fax machine. The surge protectors immediately absorbed all the power they could and produced smoke. Then the power continued on to burn out circuit boards in the equipment. I have a fairly expensive business phone system in my house, central control box and stations here and there. So, I made my own protector. I used a 10 Ohm 1 Watt film resistor in series with each incoming phone wire, and then connected to a 3-terminal gas tube arrestor. The idea is the film resistors blow like ultra-fast fuses during a severe surge, allowing the gas tube to handle what got through before. This has worked well, I've never had any damage to the phone system, but the DSL modems I used to use got blitzed a couple times. The resistors did get popped a couple times, too. I don't think you can get this kind of phone wire arrestor anywhere as a complete unit, except maybe from a telephone physical plant supplier. The gas tubes can be bought from Digi-Key and similar electronics distributors. I have had some other gear damaged, but due to the nature of the equipment, I am pretty sure it was NOT from anything coming in the power lines. Wires running from one end of your house to the other can develop thousands of Volts when there is a nearby lightning strike, due to magnetic induction. I've had some stuff in my home burglar alarm damaged, as well as an ethernet port on a computer. (Most of this damage all happened in one incident, nearby lightning strike.) So, I'm not so sure that power line protectors will actually prevent a whole lot of damage. Jon I remember at work in the early '80's (before PC) getting a whole bunch of modems and a PDP/11-23+ comm board smoked due to a near miss. The modems all turned into maracas. IT said it was induced surge on the phone lines. I saw a lot of lightning arrestor stuff going up on our feeders after that. We were about 5 miles of wire away from our nearest plant power house. After that, didn't have a problem. Coastal Texas gets a LOT of lightning. |
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