Post by thread:[EE:] Relocating house earth ground

Charles Craft said: > Am I gonna get popped when I take the clamp loose? > Should I trip the main breaker for the house to reduce the > current flowing out or is it the potential between the pole > and the earth ground that's gonna get me? Of course the official line is to take out a building permit and hire a licensed electrician to do the work, which is what I'm suggesting. However if this is purely hypothetical and we're talking about an alternate universe where lawsuits and local building codes take second priority under common sense and homeowner's rights... Unless you are the only house using your transformer (unlikely but easy to check if the wires are overhead) then if everything is working the way it should (and you better hope it is) then you have little to fear. The ground stakes of all your neighbors will keep things under control while you do your dirty work. There might even be a ground stake on the transformer at the pole. You could put a clamp-on ammeter on the ground right now and see if there's current. Cheers, Bob -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

At 02:45 PM 8/27/03 -0400, you wrote: >Charles Craft said: > >> Am I gonna get popped when I take the clamp loose? Funny story about a house without a ground. I came home one day for lunch and turned on a lamp: FLASH! burned out. Not unusual at all. Turned on another lamp: FLASH! burned out. Hmmm.... tried lamp number 3 as a test: FLASH! burned out. Suspected something was up with the power to the house. I went out the back where the service was connected and while looking around heard voices in the back alley. Looking over the fence, I saw a couple of local utility company trucks and 6 or 8 linemen having lunch and a few beers. I got the attention of the foreman and told him what just happened. Long story short, they had been working on the transformer that fed my house and left the ground disconnected. Stuff in my house was now getting powered by 220VAC instead of 110VAC. "Get off your asses and fix that line! And dump those beers!" he suggested to the crew. Other than the 3 lamps, nothing else was destroyed. The only other things on were the refridgerator and one or two clocks. If I had to move the ground on *my* house, I would leave the existing one in place until I had installed the new one. And then have some meters ready to test the result when I removed the original one. Have my beer *after* I'm done. But that's just a guess.... Good luck! Tom -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Recycling the old rod is not normally recommenced. I'd pound the new one in, hook it up (maybe an licensed electrician could help you out. They work for Beer sometimes...:) and then disconnect the old one. A bit more pounding and the old one will disappear :) Now if you house is old and your not sure if everything was done correctly.....I'd go the "Official line" too. Tim >>> .....bobblickKILLspam@spam@COVAD.NET 08/27/03 01:45PM >>> Charles Craft said: > Am I gonna get popped when I take the clamp loose? > Should I trip the main breaker for the house to reduce the > current flowing out or is it the potential between the pole > and the earth ground that's gonna get me? Of course the official line is to take out a building permit and hire a licensed electrician to do the work, which is what I'm suggesting. However if this is purely hypothetical and we're talking about an alternate universe where lawsuits and local building codes take second priority under common sense and homeowner's rights... Unless you are the only house using your transformer (unlikely but easy to check if the wires are overhead) then if everything is working the way it should (and you better hope it is) then you have little to fear. The ground stakes of all your neighbors will keep things under control while you do your dirty work. There might even be a ground stake on the transformer at the pole. You could put a clamp-on ammeter on the ground right now and see if there's current. Cheers, Bob -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

In my NEW house, if I ever get started building it anyway, there will be a piece of rebar sticking out of the floor under the panelboard. This rebar will be tied to the other rebar in the slab, not just stuck into the concrete. Yeah, I will put a silly wire to a ridiculous rod in the ground to make the inspector happy, but the real ground will be to the rebar. When I used to specify commercial panelboards, the prefferred ground was either a rebar sticking out of a concrete slab, or a cadweld onto a handy steel beam. Or both. I would usually specify at least 3 different connections to steel and concrete all coming to a single point at the main panelboard. Rebar in concrete has a far lower resistance than a copper rod driven into dry ground. BTW these methods are all recognized by NEC code. -- Lawrence Lile Tim Hart <.....Tim.HartKILLspam.....HAWORTH.COM> Sent by: pic microcontroller discussion list <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> 08/27/2003 02:19 PM Please respond to pic microcontroller discussion list To: PICLISTspam_OUTMITVMA.MIT.EDU cc: Subject: Re: [EE:] Relocating house earth ground Recycling the old rod is not normally recommenced. I'd pound the new one in, hook it up (maybe an licensed electrician could help you out. They work for Beer sometimes...:) and then disconnect the old one. A bit more pounding and the old one will disappear :) Now if you house is old and your not sure if everything was done correctly.....I'd go the "Official line" too. Tim >>> @spam@bobblickKILLspamCOVAD.NET 08/27/03 01:45PM >>> Charles Craft said: > Am I gonna get popped when I take the clamp loose? > Should I trip the main breaker for the house to reduce the > current flowing out or is it the potential between the pole > and the earth ground that's gonna get me? Of course the official line is to take out a building permit and hire a licensed electrician to do the work, which is what I'm suggesting. However if this is purely hypothetical and we're talking about an alternate universe where lawsuits and local building codes take second priority under common sense and homeowner's rights... Unless you are the only house using your transformer (unlikely but easy to check if the wires are overhead) then if everything is working the way it should (and you better hope it is) then you have little to fear. The ground stakes of all your neighbors will keep things under control while you do your dirty work. There might even be a ground stake on the transformer at the pole. You could put a clamp-on ammeter on the ground right now and see if there's current. Cheers, Bob -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

If you've never sunk a ground rod, then let me tell you a little hint. Don't pound it. Jab it into the ground and pull it out. Then pour some water in the hole. Jab it back in and watch it sink much further. Pull it out, its not that hard...really. Then pour more water in the hole, now jab it back in the hole. Keep doing this and you can sink an 8foot ground rod in about 1 or 2 minutes. Be careful, FJ From: Tim Hart <KILLspamTim.HartKILLspamHAWORTH.COM> I'd pound the new one in, _________________________________________________________________ MSN 8: Get 6 months for $9.95/month. http://join.msn.com/?page=dept/dialup -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> There was a thread last year (or 2 years ago?) about a bad earth > ground causing problems in peoples homes. > I'm trying to finish some landscaping before the snow gets here > and am at the end of the house with all the utilities. I would > like to relocate the ground rod for the house. > Am I gonna get popped when I take the clamp loose? > Should I trip the main breaker for the house to reduce the > current flowing out or is it the potential between the pole > and the earth ground that's gonna get me? There are two types of "ground" connections to your house. The first is the "common" or "center-tap" from the secondary of the pole transformer. Disconnect this wire at great risk to the appliances in your house. Without a center-tap connection, the total 220 volts from the secondary of the pole transformer has no definite way to divide. There are two branches from that transformer. The first is between one end of the secondary and the tap, and the second is between the tap and the other end of the winding. As long as the tap connection is in place, each branch sees 120 volts; remove the tap connection, and the load(s) across each branch are now in series with each other. The voltage divides according the the total impedance in each branch. The lower impedance side wins (it doesn't burn out); the higher impedance side sees more than 120 volts and bulbs, clocks, VCRs, etc burn up. The tap connection is connected to earth ground at the service entrance for your house, but that connection is not the important aspect of the situation. As long as the tap wire from the pole is continuous to your house, you won't have the above mentioned problem. The earth ground is not needed to prevent this. The earth ground exists for a different reason. The pole transformer has capacitive coupling between the primary and secondary (as all transformers do), and if the secondary is left floating, it will develop a common-mode voltage equal to the primary voltage. Since this is in the kilovolt range, there will be sparking from the internal wiring in your house. Before grounding the neutral wire at the service entrance was required, there were cases of people drawing sparks from outlets by merely passing their hands near the outlet cover plate. In some cases, fires may have been caused by sparking inside the walls of the house. If you (or someone) is going to replace the ground connection, you should guarantee that an alternate connection is in place at all times. If other houses share your drop from the pole, they may provide this for you. John Power -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

here is a link to an excellent article from Steve Ciarcia and Jeff Bachiochi of Circuit Cellar Magazine. It came to mind because of my work in the home automation industry and lightning problems we've seen with homes with multiple grounding points. The potential for voltage differentials to occur in the wiring between multiple grounding points and the ohms law results can cause problems and damage. This article talks about these types of problems. I think most of you engineers out there will enjoy this article. It even has circuit for an automatic thunderstorm switch to disconnect appliances! http://www.circuitcellar.com/pastissues/articles/Steve90/text.htm -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

In most cases you will have redundant grounds anyway. In addition to the ground rod, you should have a solid protective ground through your incoming water line (especially if it is a copper line). Even your gas pipes are often bonded to the protective ground. Bob Ammerman RAm Systems ----- Original Message ----- From: "Charles Craft" <TakeThisOuTchuckseaEraseMEspam_OUTMINDSPRING.COM> To: <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> Sent: Wednesday, August 27, 2003 8:35 PM Subject: Re: [EE:] Relocating house earth ground > Thanks for all the great feedback. > > I've decided to skip the rewiring and just pile the pine straw > a little higher on that side of the house. :-) > > thanks > > > --{Original Message removed}

> -----Original Message----- > From: Mike Singer [SMTP:EraseMEmsingerPOLUOSTROV.NET] > Sent: Thursday, August 28, 2003 6:02 AM > To: RemoveMEPICLISTEraseMEEraseMEMITVMA.MIT.EDU > Subject: Re: [EE:] Relocating house earth ground > > Bob Ammerman wrote: > > In most cases you will have redundant grounds anyway. In > > addition to the ground rod, you should have a solid > > protective ground through your incoming water line ... > > Personally I know one water pipe repairer who was seriously > injured when repairing some water pipe because some idiot > used the pipe as ground line and the power device he attached > to this "ground line" was with broken isolation. > > Mike. > In the UK all metal pipework has to be grounded by law. Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= Any questions about Bookham's E-Mail service should be directed to RemoveMEpostmasterspam_OUTKILLspambookham.com. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTspammitvma.mit.edu with SET PICList DIGEST in the body

But what if a pipe is broken between the grounding point and the point at which faulty powerful device with the broken isolation, say refrigerator, is "grounded" at it? How are you to repair the pipe? Mike. Michael Rigby-Jones wrote: {Quote hidden}> > From: Mike Singer [SMTP:EraseMEmsingerspamspamBeGonePOLUOSTROV.NET] > > Sent: Thursday, August 28, 2003 6:02 AM > > To: RemoveMEPICLISTKILLspamMITVMA.MIT.EDU > > Subject: Re: [EE:] Relocating house earth ground > > > > Bob Ammerman wrote: > > > In most cases you will have redundant grounds anyway. In > > > addition to the ground rod, you should have a solid > > > protective ground through your incoming water line ... > > > > Personally I know one water pipe repairer who was seriously > > injured when repairing some water pipe because some idiot > > used the pipe as ground line and the power device he attached > > to this "ground line" was with broken isolation. > > > > Mike. > > > In the UK all metal pipework has to be grounded by law. > > Mike -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservSTOPspamspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

Michael Rigby-Jones wrote: > > From: Mike Singer [SMTP:spamBeGonemsingerSTOPspamEraseMEPOLUOSTROV.NET] > > Sent: Thursday, August 28, 2003 6:02 AM > > To: KILLspamPICLISTspamBeGoneMITVMA.MIT.EDU > > Subject: Re: [EE:] Relocating house earth ground > > > > Bob Ammerman wrote: > > > In most cases you will have redundant grounds anyway. In > > > addition to the ground rod, you should have a solid > > > protective ground through your incoming water line ... > > > > Personally I know one water pipe repairer who was seriously > > injured when repairing some water pipe because some idiot > > used the pipe as ground line and the power device he attached > > to this "ground line" was with broken isolation. > > > > Mike. > > > In the UK all metal pipework has to be grounded by law. > > Mike > {Original Message removed}

On Thu, 28 Aug 2003, Michael Rigby-Jones wrote: {Quote hidden}> Michael Rigby-Jones wrote: > > > From: Mike Singer [SMTP:EraseMEmsingerEraseMEPOLUOSTROV.NET] > > > Sent: Thursday, August 28, 2003 6:02 AM > > > To: @spam@PICLIST@spam@spam_OUTMITVMA.MIT.EDU > > > Subject: Re: [EE:] Relocating house earth ground > > > > > > Bob Ammerman wrote: > > > > In most cases you will have redundant grounds anyway. In > > > > addition to the ground rod, you should have a solid > > > > protective ground through your incoming water line ... > > > > > > Personally I know one water pipe repairer who was seriously > > > injured when repairing some water pipe because some idiot > > > used the pipe as ground line and the power device he attached > > > to this "ground line" was with broken isolation. > > > > > > Mike. > > > > > In the UK all metal pipework has to be grounded by law. > > > > Mike > > > > {Original Message removed}

On Thu, 28 Aug 2003, Wouter van Ooijen wrote: > > Now the question: if the undergounded pipes have a smallest > > resistance > > than the proffesional house ground (which is perfect possible > > because of the > > different soil where these are undergrounded and the lenght of those > > circuits, much longer in pipes situation) the pipes corrosion > > will be huge > > Will it be? I guess you have AC mains, so there won't be much > electrolysis. > It's a very good question Wouter ! There are two reasons why it's forbidden to use pipes for electrical ground: 1. gas pipes to avoid explosions 2. water pipes to avoid corosion, the electrolysis take place between two electrodes, the earth is not a real electrode, it has a distributed resistence, various oxids etc which attack the pipe surface which is wet even in AC mode. All underground metallic pipes must be isolated (not electricaly, it's impossible) from the earth in polietilene foam. However there are plenty places where the isolation is broken. Fortunately, now there are only polietilene pipes even for 10 atmosferes. Don't you answer me about my oscillator RC question with your 5V PIC fadder conclusions ? :) best, Vasile -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

> It's true. However from my unique experience of my home builder, I have > met a strange situation. I have built an external ground connections "as > is written in the book". The final purpose was to ground all sockets > inside the house and the gas heater/boiler which is connected to the water > pipe (mine was a metallic one) to the natural gas pipe (metalic and > undergrounded) and to the room radiators via copper pipes. > I forgot to connect the external ground (builded with a lot transpiration) > to the internal circuit and I have measured inside the house the ground > resistance with a special earth bridge measuring device... Surprize. It > was perfect. Then I realised this perfect ground is the underground water > and gas pipes. > > Now the question: if the undergounded pipes have a smallest resistance > than the proffesional house ground (which is perfect possible because of the > different soil where these are undergrounded and the lenght of those > circuits, much longer in pipes situation) the pipes corrosion will be huge > and the electric "real" ground have nonsense. > > So what to do ? Nothing. > > best regards, > Vasile Remember: all of these grounds are protective grounds. Under non-fault conditions, there should be very little potential, and very little current flow involved. I expect that corrosion will not be an issue. Bob Ammerman RAm Systems -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email TakeThisOuTlistserv.....TakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Most homes have dual grounds....one tied on the incoming copper water pipe BEFORE the prv, and another safety ground tied to the ground rod. {Quote hidden}>From: Bob Blick <TakeThisOuTbobblickKILLspamspamCOVAD.NET> >Reply-To: pic microcontroller discussion list <.....PICLISTRemoveMEMITVMA.MIT.EDU> >To: RemoveMEPICLISTspamBeGoneMITVMA.MIT.EDU >Subject: Re: [EE:] Relocating house earth ground >Date: Wed, 27 Aug 2003 14:45:07 -0400 > >Charles Craft said: > > > Am I gonna get popped when I take the clamp loose? > > Should I trip the main breaker for the house to reduce the > > current flowing out or is it the potential between the pole > > and the earth ground that's gonna get me? > >Of course the official line is to take out a building permit and hire a >licensed electrician to do the work, which is what I'm suggesting. > >However if this is purely hypothetical and we're talking about an >alternate universe where lawsuits and local building codes take second >priority under common sense and homeowner's rights... > >Unless you are the only house using your transformer (unlikely but easy to >check if the wires are overhead) then if everything is working the way it >should (and you better hope it is) then you have little to fear. The >ground stakes of all your neighbors will keep things under control while >you do your dirty work. There might even be a ground stake on the >transformer at the pole. > >You could put a clamp-on ammeter on the ground right now and see if >there's current. > >Cheers, > >Bob > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. _________________________________________________________________ Help protect your PC: Get a free online virus scan at McAfee.com. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spamBeGonelistserv@spam@spam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

>I like the idea of multiple grounds but most experts recomend one and only one ground point to avoid large ground currents in storms. Perhaps the important part of that scheme is to make the tie point at the panel? Yes that is the point, and in fact it is required by code to be wired as a single point ground. You may in fact have potential between two of the tie points, but the juice will be traveling along a big thick copper ground wire between these points, not through your power system. However, ground bounce is real and there could be an issue. Some commercial systems go so far as to bury a bare copper cable in a ring all the way around the building, IN ADDITION to these other methods. I've never specified that, though. This may be needed where soil conditions make ground rods useless. In my reading on this subject, rebar in concrete in contact with soil was the absolute lowest ground resistance you could get. The ability of a 1/2" diameter steel rod to handle mega-currents is tremendous. I doubt you'd have any spalling of concrete even with a direct strike. Just anything within 10 feet would be fried. -- Lawrence Lile Senior Project Engineer Toastmaster, Inc. Division of Salton, Inc. 573-446-5661 voice 573-446-5676 fax John Ferrell <johnferrellEraseMEEARTHLINK.NET> Sent by: pic microcontroller discussion list <RemoveMEPICLISTEraseMEspam_OUTMITVMA.MIT.EDU> 08/27/2003 08:06 PM Please respond to pic microcontroller discussion list To: @spam@PICLISTRemoveMEEraseMEMITVMA.MIT.EDU cc: Subject: Re: [EE:] Relocating house earth ground A couple of items: It sounds like your specs passed inspection, so you must be right. I have been concerned about trying to ground a lightning strike through rebar, it seems to me the concrete could erupt with violence. I like the idea of multiple grounds but most experts recomend one and only one ground point to avoid large ground currents in storms. Perhaps the important part of that scheme is to make the tie point at the panel? John Ferrell 6241 Phillippi Rd Julian NC 27283 Phone: (336)685-9606 EraseMEjohnferrell@spam@earthlink.net Dixie Competition Products NSRCA 479 AMA 4190 W8CCW "My Competition is Not My Enemy" {Original Message removed}

> In my reading on this subject, rebar in concrete in contact with soil was > the absolute lowest ground resistance you could get. The ability of a > 1/2" diameter steel rod to handle mega-currents is tremendous. I doubt > you'd have any spalling of concrete even with a direct strike. Just > anything within 10 feet would be fried. > > > -- Lawrence Lile > Senior Project Engineer > Toastmaster, Inc. > Division of Salton, Inc. > 573-446-5661 voice > 573-446-5676 fax Some years ago, at the Robert Moses Niagara Power Plant, a contractor dropped an extension cord across a 115KV line. The other end of the cord was still plugged in. When the smoke cleared, we could see that the conduit to the outlet had blown out through several inches of concrete. (Luckily no one was hurt, although some new underwear may have been in order). Bob Ammerman RAm Systems -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email @spam@listservspam_OUT.....mitvma.mit.edu with SET PICList DIGEST in the body

I may have created my own problem. When I installed the Invisible Fence controller for one of my dogs, they called for a ground rod. The power ground is in the back of the house, the controller in the front, so I installed a second ground rod. When Cable TV became available, I had them put it on the front of the house to avoid the driveway (scheduled maintenance) and they were willing to use the same new rod out front. I have had several damaging strikes in the past two years. All utility service is buried. Cable, Phone and electric. I have a Ham radio tower that stays in the down position, but that is still about 30 feet. The tower has its own ground and antennas and rotator are connected only during use. Usually I get away clean, but I still have more hits than others around me... Another factor is that no one can remember the number of thunder storms being as high as it is this year. John Ferrell 6241 Phillippi Rd Julian NC 27283 Phone: (336)685-9606 spamBeGonejohnferrellEraseMEearthlink.net Dixie Competition Products NSRCA 479 AMA 4190 W8CCW "My Competition is Not My Enemy" ----- Original Message ----- From: "Michael C. Reid" <mikecreidspamBeGoneMSN.COM> To: <RemoveMEPICLIST@spam@spamBeGoneMITVMA.MIT.EDU> Sent: Thursday, August 28, 2003 2:16 PM Subject: Re: [EE:] Relocating house earth ground > the problems I've seen with multiple grounds is in a home where a second > electrical grounding rod was added as part of a room addition. A large > gauge wire was run between the two grounding rods. As described in the > Circuit Cellar magazine article, even a large gauge wire can have a voltage > drop on it when hit with millions of volts via a lightning strike. The > article also mentions the inductive effect of lightning on the wiring in a > house. And, I forgot to mention that the lightning counter circuit > described in the article has a PIC in it!!! > > {Original Message removed}

On Thu, 28 Aug 2003 .....llile@spam@EraseMESALTONUSA.COM wrote: > >I like the idea of multiple grounds but most experts recomend one and > only > one ground point to avoid large ground currents in storms. Perhaps the > important part of that scheme is to make the tie point at the panel? You've catch the point. The problem is you can't have just one ground, and in some circumstances its possible that parasitic grounds to be better than real ground. It's not relevant the point of the ground connection, and you realise that only when a serious ground resitance is performed. Another interesting thing is the currents flowing from multiple users of the same ground connections. This is never 0 even there is no malfunction on all the mains inside those buildings... > > Yes that is the point, and in fact it is required by code to be wired as a > single point ground. You may in fact have potential between two of the > tie points, but the juice will be traveling along a big thick copper > ground wire between these points, not through your power system. However, > ground bounce is real and there could be an issue. > > Some commercial systems go so far as to bury a bare copper cable in a ring > all the way around the building, IN ADDITION to these other methods. This is nothing special. It calls "low noise ground" and could be sometimes noisyest than the other standard protective ground.... :) I've > never specified that, though. This may be needed where soil conditions > make ground rods useless. > > In my reading on this subject, rebar in concrete in contact with soil was > the absolute lowest ground resistance you could get. If we use this methode than they shut us ! A protective ground in Romania ( a third country on the East of the Europe) is something much serious than rebar in concrete. I believed this methode is not used anywhere... The ability of a > 1/2" diameter steel rod to handle mega-currents is tremendous. We haven't (yet) huge storms here. The protective ground here is not for lightings but to protect people when are using indooor home electrical devices. An 1/2 steel pipe connected with another one of 4 inch and all these having more kilometers lenght may handle anything you want. But now iron pipes becomes history. Vasile I doubt {Quote hidden}> you'd have any spalling of concrete even with a direct strike. Just > anything within 10 feet would be fried. > > > -- Lawrence Lile > Senior Project Engineer > Toastmaster, Inc. > Division of Salton, Inc. > 573-446-5661 voice > 573-446-5676 fax > > > > > John Ferrell <.....johnferrellRemoveMEEARTHLINK.NET> > Sent by: pic microcontroller discussion list <.....PICLISTSTOPspam@spam@MITVMA.MIT.EDU> > 08/27/2003 08:06 PM > Please respond to pic microcontroller discussion list > > > To: PICLISTEraseME@spam@MITVMA.MIT.EDU > cc: > Subject: Re: [EE:] Relocating house earth ground > > > A couple of items: > It sounds like your specs passed inspection, so you must be right. I have > been concerned about trying to ground a lightning strike through rebar, it > seems to me the concrete could erupt with violence. > > I like the idea of multiple grounds but most experts recomend one and only > one ground point to avoid large ground currents in storms. Perhaps the > important part of that scheme is to make the tie point at the panel? > > John Ferrell > 6241 Phillippi Rd > Julian NC 27283 > Phone: (336)685-9606 > RemoveMEjohnferrellspamBeGoneearthlink.net > Dixie Competition Products > NSRCA 479 AMA 4190 W8CCW > "My Competition is Not My Enemy" > > > {Original Message removed}

Vasile Surducan wrote: > > In my reading on this subject, rebar in concrete in contact > > with soil was the absolute lowest ground resistance you > > could get. > > If we use this methode than they shut us ! > A protective ground in Romania ( a third country on the East > of the Europe) is something much serious than rebar in concrete. > I believed this methode is not used anywhere... Romania is a Central Europe country geographically, have a look at a map. It's hard to believe, Vasile, in some countries concrete reinforcing bars use to got welded all through building including basement. This makes perfect well grounded steel frame. > > The ability of a 1/2" diameter steel rod to handle > > mega-currents is tremendous. Actually Lawrence meant not just one steel rod, but rather frame of rods, in my opinion. > We haven't (yet) huge storms here. The protective ground > here is not for lightings but to protect people when are > using indoor home electrical devices. An 1/2 steel pipe > connected with another one of 4 inch and all these having > more kilometers length may handle anything you want. Have you ever built water-supply systems, Vasya? Where did you see pipes of kilometers length? Only hundreds of 6m pipes connected in series to each other by a drunken worker sometimes. The resistance of a dry connection could be very high. "To protect people when are using indoor home electrical devices" you have to equalize electrical potential of a device with the potential of walls and floor(recall frame of rods), not with the potential of some distant ground kilometers away. Best wishes, Mike. -- http://www.piclist.com hint: To leave the PICList spamBeGonepiclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu

>>pipe corrosion >Will it be? I guess you have AC mains, so there won't be much >electrolysis. Pipe corrosion depends a lot on the ground they're stuck in. They can corrode even if there is no leakage current into them (different ends of a pipe in grounds with different composition form a galvanic cell - or battery). The ac leakage into them is usually a small fraction of the telluric currents (which can be 10's of amps in certain conditions - think battery with several tens or hundreds of square meters plates). Long pipes laid in the ground always have provisions to alleviate this problem at intervals. I think that normal practice requires a pipe that is used as grounding to have a shorting bridge mounted across the part that is being repaired. Such bridges are permanently installed across gas meters and water meters to avoid the current from interfering with the meters and to allow changing the meters. I do not know what code covers this. Peter -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestspam_OUT@spam@mitvma.mit.edu

Are we talking about the ground rod at the panel box or the neutral leg? There should *never* be any current *normally* flowing through the ground wire. This is a safety wire used to drain any stray leakage, lightning, or defective neutral wiring within the house. The neutral leg and the ground rod are connected together *in* the panel box. Lifting the neutral anywhere from the panel box to the outside pole will cause all kinds of fireworks as stated by a previous post. In a properly wired house, lifting the ground from the rod temporarily, should not cause any problems. However, it should be performed by a licensed electrician because of safety and insurance liabilities. Rick C. -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestEraseMEKILLspammitvma.mit.edu

Hi All, I've got a question related to this discussion. I'm putting a DirecTV dish up at my house & the thing obviously needs to be grounded in case it gets hit bu lightning. There are several possible locations for the dish, one of them on the side of my house near my breaker box (which the builder STUPIDLY put outside the house!) and house's earth ground. Any other location would require that the dish either (a) have its own ground, or (b) have a cable run to the house's ground. Keeping in mind that the dish will have one or more coax cables running to expensive stuff in the house, where would y'all put the dish & how would you ground it? Thanks! -matt -- http://www.piclist.com hint: To leave the PICList spamBeGonepiclist-unsubscribe-requestspam_OUTRemoveMEmitvma.mit.edu

No matter where you install the dish, you must run a separate ground wire to earth via a ground rod and #6 copper wire. The amount you will spend and time involved will be far cheaper than a lightning strike or nearby strike. I would also highly recommend a *special* supressor made by Panamax. They guarantee your equipment too. Most satellite installers put this unit in all their installations. It lists for almost US$100 but they can be purchased on line for US$39.99. It also protects eight AC outlets and your phone line (especially if the satellite receiver is connected to the phone. Before I got this unit, I took a near strike and it blew my dish, receiver, Tivo, VCR, two phones, computer, dish switch, and DVD player. According to the Panamax guarantee, they would replace everything. Maybe so, maybe not, but it's still worth it. I have six satellite downlinks around the country and within the last three years, I lost three systems due to lightning. They all have this supressor and ever since, I have not lost any. I bought a dozen of them and have them on everything electronic and computer related. The model number is Powermax 8 DBS +3 and is available at: http://www.adwizards.com/lightning/ No, I don't work for them.....but should. Rick C. {Quote hidden}>BY: Matt Redmond email (remove SPAM text from address) >Hi All, >I've got a question related to this discussion. >I'm putting a DirecTV dish up at my house & the thing >obviously needs to be grounded in case it gets hit bu >lightning. >There are several possible locations for the dish, one of >them on the side of my house near my breaker box (which >the builder STUPIDLY put outside the house!) and house's >earth ground. >Any other location would require that the dish either (a) >have its own ground, or (b) have a cable run to the >house's ground. >Keeping in mind that the dish will have one or more coax >cables running to expensive stuff in the house, where >would y'all put the dish & how would you ground it? >Thanks! >-matt -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads