Surge / Ground / Lightning
in [Home Built PC]
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From: bud-- on 4 May 2008 21:38 w_tom wrote: > On May 3, 4:38 am, Franc Zabkar <fzab...(a)iinternode.on.net> wrote: >> Can you elaborate on this by showing us the path taken by the strike >> through the TV? > > See many posts that describe this same failure to a network of > powered off computers. Surge incoming on wires that typically carry > most surges into buildings: black (hot) AC wire. Surge arrived two > plug-in protectors - each adjacent to powered off computers. Often > that surge is trivial; does not overwhelm protection inside a > computer's power supply. Maybe - but irrelevant due to the adjacent > protector. > > Protector did its job - MOVs shunted (connected, diverted) surge > current into all other AC wires including the green safety ground > wire. Green wire connects directly to motherboard and network cards - > still seeking earth ground. > > Path to earth was through the network and into a third computer. > Through that third computer's motherboard, through modem, and to earth > via phone lines. Semiconductors in these paths were damaged. Any competent source (including the IEEE guide) along with any competent manufacturer will tell you all interconnected equipment needs to be connected to the same plug-in suppressor, or interconnecting wires need to go through the suppressor. External connections, like phone, also need to go through the suppressor. Connecting all wiring through the suppressor prevents damaging voltages between wires going to the protected equipment. This is apparently way to complicated for w_ to understand. For a more detailed explanation, read (starting pdf page 39) the IEEE guide titled "Ground potential rise" http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf The same section explains how plug-in suppressors work. > > Plug-in protector is not for and does not claim to protect from this > typically destructive type of surge. Complete nonsense. Just another of w_'s bizarre ideas. > But the same > ineffective protection is demonstrated in Bud's citation - 8000 volts > destructively on Page 42 Figure 8. That surge was permitted inside > the building. Plug-in protector did nothing to avert 8000 volts > destructively via the adjacent TV. The illustration in the IEEE guide has a surge coming in on a cable service. There are 2 TVs, one is on a plug-in suppressor. The plug-in suppressor protects TV1, connected to it. The point of the illustration for the IEEE is "to protect TV2, a second multiport protector located at TV2 is required." Apparently a radical idea for w_. w_ says suppressors must only be at the service panel. In this example a service panel protector would provide absolutely *NO* protection. The problem is the wire connecting the cable entry block to the power service 'ground' is too long. The IEEE guide says in that case "the only effective way of protecting the equipment is to use a multiport protector." > > What would have avoided above network damage? Homeowner later > installed and earthed a 'whole house' protector. A power service suppressor is a real good idea. It does not protect equipment connected to both power and signal wires if there is a high voltage between those wires as in the example above. There are other hazards that it also misses. For independent advice read the IEEE or NIST guides. (Both say plug-in suppressors are effective). -- bud--
From: bud-- on 4 May 2008 21:47 w_tom wrote: > On May 3, 6:40 am, phil-news-nos...(a)ipal.net wrote: > > Bud claims plug-in protectors provide a complete protection system - > can protect from all types of surges. A plug-in protector only > protects from surges that rarely damage appliances. Complete nonsense. > > If not using a 'whole house' protector, well, even 'scary pictures' > created by typically undersized protectors now creates a hazard. The lie resurrected. Still missing - a link to any source that says UL listed plug-in suppressors made after 1998 are a problem. And undersized is a red herring. UL requires at least a minimal size. Suppressors with much higher ratings are readily and cheaply available. > > Bud disputes this. Bud says if all wires connect to the same > protector, then surge energy somehow disappears. Poor w__ is unable to understand the IEEE guide. Clearly explained (starting pdf page 40) - plug-in suppressors work primarily by CLAMPING 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 stopping or absorbing). The guide also explains earthing occurs elsewhere, not through the plug-in suppressor. Still never seen - a source that agrees with w_ that plug-in suppressors are NOT effective. Still never seen - answers to simple questions: - Why do the only 2 examples of surge suppression in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why do all but one of w's "responsible manufacturers" make plug-in suppressors? - Why does SquareD say in addition to their "whole house" suppressors "electronic equipment may need additional protection" from plug-in suppressors. - Why aren't airplanes crashing daily when they get hit by lightning (or do they drag an earthing chain)? For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective. -- bud--
From: bud-- on 4 May 2008 21:57 phil-news-nospam(a)ipal.net wrote: > > Bud is focusing on the low frequency energy and > seems to think that is all there us because a lot of documents focus > on it because more energy is in the low frequencies. Also, surges > that come from a greater distance have the higher frequencies reduced. > > Bud either does not understand the high frequency energy or just does > not believe it can happen. All lightning strikes have it. Bud has provided 2 sources that directly contradict Phil. (Of course they are not as smart as Phil.) Phil has provided no sources to support Phil's Phantasy Physics. (But this is *Phil* - why should he need sources?) -- bud--
From: w_tom on 4 May 2008 22:03 On May 4, 2:55 pm, phil-news-nos...(a)ipal.net wrote: > I don't agree with that assessment of the plug-in protector. If the > appliance has its own MOVs to protect stuff, then this would be true. > Not all do. Some appliances are more sensitive than others. It just > depends on what kind of surge is arriving, and where from. If it is > differential mode on the power wires, the plug-in protector can do > some important protection. Even with whole house protection in place, > you can have some energy get past it, and the surge can be induced into > the building wiring. Usually the induced surge is common mode, which > by itself is less of a problem. In short, your post is saying what my post said. 120 volt electronics have long had protection up to 600 volts as defined by industry standards. This was always accomplished without MOVs. Notice all the dimmer switches replaced weekly due to surge damage? Not replaced because even those devices contain significant internal protection - without MOVs. The differential mode surge (what a plug-in protector can protect from) typically does no damage as indicated by the large numbers of appliances - even smoke detectors - that survive these trivial surges. Survive without MOV protectors because internal protetion is provided as part of the design - not an add on provided by MOVs. The typically destructive surge occurs maybe one every seven years. This is the surge that must be earthing before entering building. This is the surge that so easily overwhelms protection inside appliances. This is the surge that makes the properly earthing 'whole house' protector necessary and so effective. Yes, it is possible to make other protectors - absorption type. Industry benchmarks also provide other examples including bulkheads. Surges running through these bulkheads are further impeded. But each is supplementary protection. To be effective, typically quite large or expensive (Surgex, Brickwall, Zerosurge, etc). . How much is one willing to spend? Effective supplmentary protection is also quite expensive. Anything less is already found inside an appliance. Yes, a plug-in protector can provide protection. Does it increase protection by 80% or 95%. Protection so massive that the homeowner may never see another surge in his lifetime?. Even a simplest (properly installed) 'whole house' protector should provide protection that significant. Without that 'whole hosue' protector, then plug-in protectors may even contribute to appliance damage. To be effective - to not contribute to damage of an adjacent appliance, a plug-in protector needs a properly earthed 'whole house' system. Again, I have not talked pass Bud. Bud promotes supplemental protection as a complete solution. Defined by you and I are a surge a plug-in protector might protect from AND why a plug-in protector can also contribute to appliance damage. Yes, your TV antenna examples are also correct - including how either can be damaged. That being too complicated for most readers AND irrelevant if both antenna wires are properly installed. Before antenna wires enter a building, both antenna wires must first make a short connection to the single point earth ground - meaning protection standard in TV tuners should not be overwhelmed. Same protection also installed by the cable company. Only Bud is limiting himself to one aspect of the issue. You and I are both discussing the many types of surges including the other that typically causes most damage. Bud must ignore that typically destructive surge. Those surges also create Page 42 Figure 8 - 8000 volt earthed destructively through an adjacent TV. Those surges are why his other citation says: > The best surge protection in the world can > be useless if grounding is not done properly. Those surges that typically do damage AND that plug-in protectors do not claim to protect from - Bud ignores that entire discussion.
From: bud-- on 4 May 2008 22:15
phil-news-nospam(a)ipal.net wrote: > In alt.engineering.electrical Leonard Caillouet <nospam(a)noway.com> wrote: > | <phil-news-nospam(a)ipal.net> wrote in message > | news:fvjhvk016vr(a)news5.newsguy.com... > |> In alt.tv.tech.hdtv Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: > | > |> > |> The MOVs will act like conductors when they are clamping. The surge will > |> take both paths ... the path through the MOVs, and the path going past the > |> MOVs. In general, about 50% will go each way. That can vary at higher > |> frequencies. > | > | Why would you assume that 50% will go each way when you don't know the > | impedance of each direction? When conducting, or at failure, the MOV has a > | very low impedance. > > There is a distinction between "go each way" and "what comes back" due to > the impedance. It will be about 50% that goes each way _because_ the power > itself does not (yet) know the impedance (at a distance), until it gets > there. Another installment of Phil's Phantasy Physics using transmission line theory. Two sources directly contradict Phil. Phil has provided no sources to support phantasy physics. -- bud-- |