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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue May 25, 2010 5:02 pm Post subject: |
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| David_Web wrote: | And the times you can't unplug?
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Make sure your homeowners policy is paid to date.
Or keep your fingers crossed.
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Tue May 25, 2010 5:51 pm Post subject: |
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| David_Web wrote: | Ill have too look over the ground. Maybe add one if needed. Can't hurt. Otherwise the electrical should be fine as no dimmers or other equipment is broken yet. ...
How about the phone line? |
As you understand, unplugging is a least reliable solution. But when others 'feel' they are doing something, then it must be better. The effective solutions exist 24/7/52 every year. And destructive surges occur maybe once every seven years.
Three AC wires enter the building. Only one might be grounded. Other two AC wires carry a direct lightning strike (to utility wires down the street) directly into household appliances. Those other two create a direct lightning strike to appliances if not connected to earth ground via a 'whole house' protector. The world's best earth ground is useless if all three wires do not connect.
All phone lines already have a 'whole house' protector installed for free - as noted previously. But again - a protector is only as effective as its earth ground. If someone screwed up big time - if a phone enters the building somewhere else, then a best (installed for free) protector is compromised. It has no single point ground.
One utility demonstrates how to kludge a solution. See "Preventing Damage Due to Ground Potential Difference" to correct an ugly installation with an enlarged single point ground:
http://tinyurl.com/yefm8n9 or
http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-08.asp
Any wire that enters a building (even underground) without connecting to single point ground means energy will be inside the building. Energy will hunt for earth destructively via appliances. An application note entitled "The Need for Coordinated Protection" at:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf
demonstrates how single point ground for two structures are implemented. Any wire between two structures must connect to each single point ground. Otherwise one structure acts like a lightning rod connected directly to electronics in the other building.
There is not and never was another reliable solution. Because protection is always about where energy dissipates.
Moving on: inspecting your earth ground. That wire from breaker box 'whole house' protector to earth must be short (ie less than 10 feet). Separated from other wires. No sharp bends. No splices. If that quarter inch bare copper (6 AWG) wire goes up over the foundation and down to earth, then it is too long. Too many sharp bends. Adjacent to all other wires leaving the breaker box. It must go through the foundation and down to single point earth ground. Eliminate the sharp bends. Separated from other wires. And most critical - made every single one foot shorter.
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Cube
Joined: 06 Dec 2009
Posts: 77
Location: IL, USA
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| Posted: Wed May 26, 2010 5:15 pm Post subject: |
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You said that surges go out via a phone line. That's interesting because the only time I had something damaged by a surge, it was a MOV strip with phone jack. The equipment attached to it was unharmed.
Every time there's a lightning strike nearby (several miles), the DSL connection times out and resets. That's usually the only symptom. One time there was a strike very close and the connection dropped to half speed until I replaced the MOV strip. If the surge was seeking ground through the phone line and damaged the strip, that means it passed through my DSL modem (at least) first without causing any apparent damage. More evidence that power strips are pointless? Also, in 15 years of being plugged straight into the outlet, the fuse on the old projector never blew.
I checked my circuit breaker but I can't tell how it's grounded. There aren't any pipes in the room to attach to. Where would I look into having an earthing bar or something sunk in my lawn? How do you drill through the foundation wall to connect to the earth?
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Wed May 26, 2010 6:14 pm Post subject: |
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| Cube wrote: | You said that surges go out via a phone line. That's interesting because the only time I had something damaged by a surge, it was a MOV strip with phone jack. The equipment attached to it was unharmed.
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You completely missed the point. No ground inside a room is earth ground. If I did not say it enough - single point earth ground. Not digital ground in a computer. Not floating ground in a TV. Not the metal box called a refrigerator that is a ground. Not grounded to plumbing.
All homes must have another ground called the earth ground. Find a bare copper quarter inch (6 AWG) wire from breaker box to an earthing electrode just outside. If that does not exist, then your earthing does not meet post 1990 National Electrical code - essential for human safety. Human safety demands that ground exist. Previous posts were about earthing that must meet and exceed those NEC requirements - for transistor safety.
You cannot ground to any pipes. That is a human safety violation. And much too long to earth ground. Single point earth ground, short ('less than 10 foot') connection, no sharp wire bends (or pipe joints), separated from other non-grounding wires ... and other relevant factors. All are reasons why one 'whole house' protector is so effective. And why that is the solution in facilities that must never have damage.
Your DSL drop out is classic noise - not a surge. Maybe a few volts on the wire - not thousands of volts. Even the 'installed for free', 'whole house' protector on your phone lines ignores that noise. Did you know that protector exists?
Your examples are classic of bad science. Remember that claim of childhood leukemia from electric lines? He simply did what you are doing. He threw out all other facts to make his conclusion work. You did same.
Your examples are valid ONLY IF all other unprotected appliances are damage. You had many surges? Every dimmer switch (some of the least robust appliances in a house) were destroyed with each surge? Must be for your reasoning to be valid. Dishwasher was replaced every time? Why not? Is it on an invisible protector? According to your logic, it too was destroyed. Your "this was not damaged" reasoning is valid only when all other unprotected appliances (such as the furnace) were damaged. Did you now all appliances have internal surge protection?
So how often do destructive surges exist? Another problem with your reasoning. Typically once every seven years. But your projector was not damaged? How many air conditioners and smoke detectors did you replace during every surge that did not damage the projector? Or are they also on invisible protectors? Only way your logic can prove anything - all those other undamaged appliances must be on invisible protectors. A majority of appliances not on protectors also were not damaged. Because surges are that rare. And because all appliance already have significant surge protection internally. Some better than others. And due to other factors you also needed to know before making a conclusion.
Circuit breakers are not grounded. And no circuit breaker does surge protection - again for a very long list of reasons such as "A surge is done in microseconds. A circuit breaker takes milliseconds to trip."
Every wire inside every cable must connect to earth ground. Either connected directly - cable TV. Or earthed via a 'whole house' protector: telephone and AC mains. If you do not have a 'whole house' protector in the breaker box, then lightning down the street connects directly (ungrounded) to every appliance in the house. Once you permit that energy into the building, then it will hunt for earth destructively via appliances. It is that simple. Effective protection always means that energy does not enter the building. Protection is always about where that energy dissipates. Always.
Effective protector means a direct lightning strike is absorbed harmlessly outside the building. And that nothing inside a building is damaged. AND the protector that earthed the entire lightning strike remains functional. Nothing new. These 100 year old solutions were implemented throughout the world where damage must never happen - ie munitions dumps. Solutions that were well proven generations before computers even existed. Same knowledge that also says a protector adjacent to the DSL modem is ineffective.
Only ineffective (grossly undersized to maximize profits) protector fail with a surge. That failure gets the naive to promote the protector. Effective protection means nobody knew the surge existed. Even the protector remains functional after a direct lightning strike. It costs about $1 per protected appliance. How much was that power strip protector? $25 or $150 per …?
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Cube
Joined: 06 Dec 2009
Posts: 77
Location: IL, USA
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| Posted: Wed May 26, 2010 7:02 pm Post subject: |
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I think you misunderstood what I said. I'm not making some claim about the efficacy of MOVs, I'm pointing out that I have never actually had anything damaged by a surge (or what I thought was a surge) except a DSL line MOV strip that began to interfere with the connection after lightning struck nearby. I figured that caused a surge that damaged the strip, but I don't know. In any case, nothing else was damaged to my knowledge by a surge then or at any other time, and this house is more than 20 years old. Does this mean my AC line is probably well-grounded to earth already? Have I been lucky and there has never actually been a surge in my house?
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Wed May 26, 2010 7:12 pm Post subject: |
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| Cube wrote: | | I think you misunderstood what I said. I'm not making some claim about the efficacy of MOVs, I'm pointing out that I have never actually had anything damaged by a surge (or what I thought was a surge) except a DSL line MOV strip that began to interfere with the connection after lightning struck nearby. I figured that caused a surge that damaged the strip, but I don't know. In any case, nothing else was damaged to my knowledge by a surge then or at any other time, and this house is more than 20 years old. Does this mean my AC line is probably well-grounded to earth already? Have I been lucky and there has never actually been a surge in my house? |
If your house was built in the last 20 years then more then likely it was installed per NEC code at that time which is still valid other then minor alterations. Now this also depends on where you live and the requirement of the local authority. Which in some locations doesn't exist. But should matter if the main service was installed by a professional electrical or even by someone with code knowledge.
If your not sure and/or just want to make sure your service is up to current NEC code then just call a local electrician and ask then to come and check your service. It would be worth the service call fee just to set your mind at ease. Some states/counties have inspectors that come out and check for free.
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Wed May 26, 2010 11:51 pm Post subject: |
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| Cube wrote: | | ... this house is more than 20 years old. Does this mean my AC line is probably well-grounded to earth already? Have I been lucky and there has never actually been a surge in my house? |
Reply deleted by author - it was reposted below when the first post never appeared.
Last edited by westom on Thu May 27, 2010 12:03 am; edited 1 time in total
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Wed May 26, 2010 11:54 pm Post subject: |
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| westom wrote: | | Cube wrote: | | ... this house is more than 20 years old. Does this mean my AC line is probably well-grounded to earth already? Have I been lucky and there has never actually been a surge in my house? |
A house can be wired in the 1930s - and easily meet and exceed post 1990 code for earthing. Nothing inside need be upgraded. The concept is single point earth ground. Every wire that enters the building must connect short to that ground.
AC electric has three wires. Only one is connected directly to earth. Without a 'whole house' protector, then AC electric still is not earthed. Earthed for human safety. Not earthed for transistor safety.
Inspection: a bare copper 6 AWG wire is from the breaker box to an earthing electrode outside the building. At minimum, this should be an 8 foot copper clad steel rod. That ground wire from breaker box to that earthing electrode should be routes as short as possible. That means not over the foundation and down. That is acceptable to meet the 1990 National Electrical code - for human safety. But we must exceed code - for transistor safety. Better is to reroute that ground wire through the foundation and down to the earthing electrode.
Now that ground wire earths one of three incoming AC wires. More responsible companies (Siemens, Intermatic, Leviton, Square D, General Electric, etc) sell the 'whole house' protector. That one device connects those other two AC electric wires to that ground wire and earth.
Lightning most often strikes wires highest on utility poles. That is AC electric. Lightning seeks earth ground. If you have upgraded earthing and installed a 'whole house' protector, then lightning (and other surges) have no reason to hunt for earth inside your building; destructively via appliances.
Most typically do not understand anything posted here until they touch it. A minimally sized 'whole house' protector from Cutler Hammer sells in Lowes and Home Depot for less than $50. Ask the salesman to also show you ten foot long copper clad ground rods.
Now, this is a surge on AC electric. A surge can enter on phone lines. But all phone lines already have a 'whole house' protector install for free by the telco. Why? Because these protectors are so effective AND costs so little money. But that telco protector does nothing if you do not provide (upgrade) earth ground. Only you are responsible for earthing. Your earthing must also connect 'less than 10 feet' to that telco installed protector.
Cable TV needs no protector. What does a protector do? Connects a surge to protection. Cable TV gets connected only with a wire. Again, the wire from cable TV must meet all grounding wires at the earthing electrode - the single point earth ground.
Any 1930, 1950, or 2010 home can easily implement this well proven solution. Protection is always about where energy dissipates - harmlessly in the single point earth ground. Every protector is only as effective as the earth ground it connects to. Your AC electric is only properly grounded when all three AC wires (not just one) connect short to earth. If you do not have a 'whole house' protector, then your AC electric is still not earthed.
macgyver655's suggestion is strongly encouraged. If you still don't get it, then get that electrician to show you what you should learn. Only you are responsible for that earthing. In one rare case, a house literally exploded because that earth ground was somehow missing. House used a gas meter to obtain earth - explosively. Fortunately nobody was home. Did his suggestion get your attention? Only a homeowner is responsible for getting it right. Only the homeowner can get himself informed.
How often do destructive surges occur? All appliances contain serious protection. Your concern is the rare surge that can overwhelm that protection - typically once every seven years. How frequent is the risk. A neighborhood history of at least then years might better answer that question. Some locations may suffer surges every two or four years. Some may not see one in 20 years. Only you can determine the risk. |
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David_Web
Joined: 02 May 2007
Posts: 418
Location: Sweden
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| Posted: Thu May 27, 2010 10:25 am Post subject: |
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"All phone lines already have a 'whole house' protector installed for free - as noted previously."
Not sure that I have seen one, who should I contact to get one installed for free here in Sweden?
You mention it is cheap, where can I find one and install it myself if that is the case? What does it look like?
If there was one then it did a very poor job the last time lightning hit.
Same for several people on the street. Only things attached to phone line got damaged.
Would this be an issue caused by badly protected distribution by the tele company?
You are right that it does not happen very often, probably 10 years since last time.
_________________
SNR of people are ridiculously low.
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westom
Joined: 14 Dec 2009
Posts: 56
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jun 01, 2010 9:04 am Post subject: |
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Reading through this, and being in the electrical trade, i am not quite sure how these items are allowed to make it to the store shelves. That is just piss poor standards. Really piss poor. Where the standards are letting you down i cant say without reading your standards book, but if that passes, i cant see it taking me long to read.
Im not sure what your socket outlets are rated, what size cable is run, or what the load limit for each circuit is required to be, but in those cases i cant see how that could be of a low enough resistance to get so hot and not blow the circuit protection fuse or the circuit breaker in your switch board.
While on the subject of surge protection, the BEST way to protect against surges is to use an MOV that diverts excess energy to earth, and have that said circuit protected by an RCD ( residual current device ), when the MOV diverts anything to earth, the RCD will cut power as soon as it reaches the specified delta. It does so by measuring the magnetic field around active and neutral, which should be zero unless there is earth leakage. The current flow should be the same through the active and the neutral, which will cancel any magnetic field, so as soon as some current tries to return through earth, the active is then passing more current than the neutral, and the RCD will break the circuit in around 30ms when the rated delta is reached.
Sure in doing that youll have to walk out to the box and reset the RCD, but you wont have a fire, and your gear wont be shot to sh*t either. If the stuff has to run, put a UPS AFTER the MOV protection device.
I dont know what your electrical instalation standards are like over there, but here in Australia and also in NZ which is pretty much the same standards, they are quite high in most respects. Im aware that over there you can wire your house or make alterations to wiring without an electrical licence, which i think is sheer lunacy. But that is just me.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jun 01, 2010 9:38 am Post subject: |
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Just to further elaborate on the RCD issue, here is a link: http://en.wikipedia.org/wiki/Residual-current_device which explains the device and how it works.
The regulations part does not indicate that there is a requirement for these in the USA, and also incorrectly indicates their requirement in Australia, where they say some states require their use on all power and lighting circuits, it should say ALL states require them on all domestic power and lighting circuits in NEW installations, and have done since about 1995 or 96, pre-existing installations do not require their installation unless modified. All states in Australia are bound by the same standard, which is also the same standard in almost every case for New Zealand, and is the AS/NZ 3000:2007 wiring rules.
Ill also add that an RCD on its own wont protect against over current, there is a combined device for that called an RCBO, however an RCD downstream from a suitable over current protection device will do the same job combined.
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Tue Jun 01, 2010 3:34 pm Post subject: |
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| CasetheCorvetteman wrote: | Reading through this, and being in the electrical trade, i am not quite sure how these items are allowed to make it to the store shelves. That is just piss poor standards. ...
While on the subject of surge protection, the BEST way to protect against surges is to use an MOV that diverts excess energy to earth, and have that said circuit protected by an RCD ( residual current device ), when the MOV diverts anything to earth, the RCD will cut power as soon as it reaches the specified delta. |
Those devices work safe as power strips. Meet UL standards (similar to Australian) in an attempt to avoid those scary pictures. Power strip protectors in Australia have same safety problems.
Using an RCD will not solve the problem. Surges are done in microseconds. Your RCD takes forever – 30 milliseconds. If an RCD trips due to excessive current (an MOV failure), then nobody wants that RCD reset. MOVs first must be removed.
Protectors contain a thermal fuse so that MOVs are permanently disconnected during a larger surge. So a protector circuit remains disconnected. A protector should be sufficiently sized so that it does not fail catastrophically. The associated thermal fuse is only an emergency backup system; should not be primary protection of human life.
North America has numerous RCD type devices. The basic type required in the 1970s is called a GFCI. Another type to protect from arcing (fire) was first required by code in 2002; called AFGI.
An RCD would not respond fast enough to avert the overcurrent known as a surge. And if it did, surge voltage increases as necessary to blow through an RCD. RCDs do not stop surges.
UPS has the same protector circuit used in power strip protectors – just smaller. Near zero surge protection so that a sale brochure can claim 100% protection. No adjacent UPS provides effective protection. One reason makes that obvious. That protector circuit is too far – more than 3 meters – from earth ground.
For effective protection, an earthing wire must be separated from other non-grounding wires, not in metallic conduit, no sharp wire bends (that are found in every electrical box), no splices, and short (ie ‘less than 3 meters’) to single point earth ground. Safety ground (in wall receptacles) is not earth ground for these and other reasons. Wire to earth a surge must meet requirements for human safety grounds due to wire impedance.
A short distance to single point earthing is critical for surge protection which is why Telstra locates their protector adjacent to earth ground - and up to 50 meters distant from electronics.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Jun 01, 2010 3:51 pm Post subject: |
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We had a very severe lightning storm here last night. Upon seeing the first flash in the sky I walked around the house unplugging anything of extra value. Took me a whole 2 or 3 minutes...if that........... Nothing was lost..... 
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Tue Jun 01, 2010 5:04 pm Post subject: |
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| macgyver655 wrote: | | We had a very severe lightning storm here last night. Upon seeing the first flash in the sky I walked around the house unplugging anything of extra value. Took me a whole 2 or 3 minutes...if that........... Nothing was lost..... |
I totally agree with the un-plugging thing but.......................What if you're not home when the time is right 
I still swear by my solution, even more so if it were a digital. Nothing worse for a lamp machine than to pull the plug with a smoking hot lamp. With a UPS. you have time to shut it down and let the post purge fan do it's thing.
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A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Jun 01, 2010 5:14 pm Post subject: |
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| stefuel wrote: |
I totally agree with the un-plugging thing but.......................What if you're not home when the time is right
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If I am leaving the house and know their might be a storm coming (watched the weather report) I go around unplugging before I leave. Again, 2 or 3 minutes, tops. And if I'm leaving for an extended period of time (traveling), all is unplugged.
And whats funny is, I do this when I could really just fix the stuff myself if it did get hit. Maybe its because I have seen so much stuff that has been hit.
And before anyone throws a side comment in here, yes, I also disconnect my roof antenna and internet line.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jun 01, 2010 10:01 pm Post subject: |
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| westom wrote: |
Those devices work safe as power strips. Meet UL standards (similar to Australian) in an attempt to avoid those scary pictures. Power strip protectors in Australia have same safety problems.
Using an RCD will not solve the problem. Surges are done in microseconds. Your RCD takes forever – 30 milliseconds. If an RCD trips due to excessive current (an MOV failure), then nobody wants that RCD reset. MOVs first must be removed.
Protectors contain a thermal fuse so that MOVs are permanently disconnected during a larger surge. So a protector circuit remains disconnected. A protector should be sufficiently sized so that it does not fail catastrophically. The associated thermal fuse is only an emergency backup system; should not be primary protection of human life.
North America has numerous RCD type devices. The basic type required in the 1970s is called a GFCI. Another type to protect from arcing (fire) was first required by code in 2002; called AFGI.
An RCD would not respond fast enough to avert the overcurrent known as a surge. And if it did, surge voltage increases as necessary to blow through an RCD. RCDs do not stop surges.
UPS has the same protector circuit used in power strip protectors – just smaller. Near zero surge protection so that a sale brochure can claim 100% protection. No adjacent UPS provides effective protection. One reason makes that obvious. That protector circuit is too far – more than 3 meters – from earth ground.
For effective protection, an earthing wire must be separated from other non-grounding wires, not in metallic conduit, no sharp wire bends (that are found in every electrical box), no splices, and short (ie ‘less than 3 meters’) to single point earth ground. Safety ground (in wall receptacles) is not earth ground for these and other reasons. Wire to earth a surge must meet requirements for human safety grounds due to wire impedance.
A short distance to single point earthing is critical for surge protection which is why Telstra locates their protector adjacent to earth ground - and up to 50 meters distant from electronics. |
Never at any point did i say an RCD will trip for over current, cause it will not, that is not how an RCD works. And RCBO will do the job of an RCD as well as a circuit breaker.
Never at any point did i say an RCD will PREVENT or STOP a surge, what i said was it will DISCONNECT the supply in the event of over voltage being diverted to earth, which it most certainly will. The MOV is still in the line to clip the surge and divert it to earth ( which most do not, they divert to neutral ), which gives the RCD its order to drop out, no power connected, no chance of fire, and no chance of further surges.
If a surge is going to be so big itll jump the gap inside a circuit breaker / RCD / RCBO, then the voltage and resulting current flow is far more substantial than any MOV is going to contain. How many ohms between the open contacts on a circuit breaker / RCD / RCBO? Lots. Massive resistance, way up in the megaohms range, lots of volts required to overcome that resistance.
Never at any point did i say to use a UPS to prevent surges either, i said use one to continue supply of power after a cut out of any kind.
And what is this all about? "If an RCD trips due to excessive current (an MOV failure), then nobody wants that RCD reset." Ofcourse they want it reset, and the RCD wont trip due to over current. The circuit breaker or RCBO does the over current protection, NOT the RCD. No harm in reseting it, if the fault still exsists, itll trip before you can even get it latched in.
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Wed Jun 02, 2010 12:53 am Post subject: |
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| CasetheCorvetteman wrote: | If a surge is going to be so big itll jump the gap inside a circuit breaker / RCD / RCBO, then the voltage and resulting current flow is far more substantial than any MOV is going to contain. ...
Never at any point did i say to use a UPS to prevent surges either, i said use one to continue supply of power after a cut out of any kind. |
'Whole house' (MOV) protector is for surges that will jump the gap in a circuit breaker / RCD / RDBO etc. If a circuit breaker etc opens to disconnect during a surge, 300 consecutive surges would flow through that circuit breakers, RCDs, etc. Those devices still will not disconnect fast enough due to a surge.
Circuit breakers, etc are not for protecting appliances or disconnecting a protector. Its only purpose to protect human life after damage has happened. That 30 millisecond number says that.
In a discussion of surge protection; RCD, RCBO, circuit breaker, and UPS have no relevance. UPS is to provide temporary power during blackouts and extreme brownouts for data protection. Not for hardware protection. Breaker etc is for human safety. Ie to stop what would cause a fire. Functions that are completely different from surge protection.
Surge protection is about current. Voltage only increases, as necessary, to blow through any blocking device (ie circuit breaker, fuse, filter). High voltage indicates effective protection does not exist. High voltage indicates a surge is inside the building hunting for earth destructively via appliances. Effective protection means that current is not inside the building.
Surges that can damage undersized power strip protectors often do not overwhelm protection inside appliances. Primary reason for earthing a surge protector. So that a surge does not overwhelm appliance internal protection. Same surge that can jump millimeter gaps in circuit breakers, power switches, UPS relays, and other disconnecting devices. That is the surge that an effective protector connects short (ie 'less than 3 meters') to earth. Only then is a current mode transient diverted harmlessly to earth so that no high voltage exists.
I'm not sure which electrical anomaly you are addressing. Devices for overcurrent, to detect current leakage, or to protect data from power loss do not address another anomaly called a surge.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Jun 02, 2010 8:09 am Post subject: |
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Im not going to argue the point with you any further, ive stated pretty clearly what i meant, and that was in relation to small surges that are more commonly occuring. I didnt say the whole house MOV is not a good idea, i simply stated what is a very effective means of small surge protection.
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westom
Joined: 14 Dec 2009
Posts: 56
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| Posted: Wed Jun 02, 2010 10:39 pm Post subject: |
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| CasetheCorvetteman wrote: | | ... ive stated pretty clearly what i meant, and that was in relation to small surges that are more commonly occuring. I didnt say the whole house MOV is not a good idea, i simply stated what is a very effective means of small surge protection. |
View what most fire departments have seen when a plug-in protector is not protected by a 'whole house' protector. Scary pictures when a protector attempts to absorb hundreds of thousands of joules when that protector circuit did not disconnect fast enough:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol
http://www3.cw56.com/news/articles/local/BO63312/
http://www.nmsu.edu/~safety/news/lesson-learned/surgeprotectorfire.htm
http://www.pennsburgfireco.com/fullstory.php?58339
Discussion is about how spending hundreds for plug-in protectors that are not just ineffective - that do not claim to protect that home theater. Sometimes it can contribute to appliance damage. Sometimes it create a human safety problem - especially if located in the ceiling. Must be protected by a ‘whole house’ protector.
Meanwhile, one 'whole house' protectors makes the plug-in protector unnecessary.
A protector that fails during a surge (disconnects leaving the appliance connected to that surge) is ineffective. Scary pictures are just another reason why we waste no money on plug-in protectors. If a protector fails, then it does not provide effective protection. Sometimes that failure creates those scary pictures. But failure gets the naive to recommend that protector for 'small surges'.
So that energy dissipates harmlessly outside a building, an informed consumer earths one 'whole house' protector for about $1 per protected appliance. And does not spend $25 or $150 per for protectors that do not even claim protection from typically destructive surges. How to quickly identify more popular and ineffective protectors. It has no short and dedicates wire to earth ground. A protector is only as effective as its earth ground.
One whole house protector also means the homeowner unplugs nothing. Uses electronics during thunderstorms. And does not come home to a surge damaged refrigerator, digital clocks, furnace or air conditioner, and dishwasher, dimmer switches, RCD (or GFCI), and smoke detectors. The only effective solution is to earth only one 'whole house' protector so that human failure does not result in appliance damage.
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