1950s Houses, Mains Earthing, and the Cable Guy. - Page 1
Forum section: electronics / beginners

author: SgtRock
author_rank: Unknown
timestamp: September 05, 2011, 03:31:37 am
content: Greeting EEVBees:--Herein pends a long tale of woe, with an eventual happy ending.--My neighborhood is composed of 1950s houses. Many have original 2 wire runs from the breaker box to the sockets. My neighbor's house had 2 wire cable running to the sockets, but of course some jake leg had hooked up 3 pin sockets to the 2 wire cable and left the ground unconnected. This is a very common practice in my neighborhood, and is probably endemic in similar situations in the US.--My neighbor, Mike, was having a lot of trouble with his BrightHouse internet connection going intermittent at odd intervals. I had him get a good UPS and hooked it up for him. When I hooked up the UPS I noticed that the "No Ground" light was lit up. I checked the socket, and "Bobs your uncle" there was no ground. I did notice however that if I ran the BrightHouse cable through the UPS it would pick up the ground from the BrightHouse cable. Parenthetically, I should add that both Mike and I were in the Poor House at the time, so calling a licensed electrician was out of the question. Problem solved??--It turns out that although his computer, router, etc. was now protected from spikes and short term outages, the internet connection was still fritzy.--Mike would call, and the cable guy would come out and say; "Well there's your problem, you have the cable run through the UPS. That interferes with our signal." I pointed out to the BH man that the problem predated the installation of the UPS and that I had been running an identical setup at my house for two years with no problems. Needless to say, my statement had no effect on the BH man. He disconnected the UPS, pronounced the problem solved and left, mumbling and shaking his head at the stupidity of customers.--Surprisingly, the intermittent outages continued, and Mike would re-engage the UPS, call BH and the whole scenario would repeat ad nauseum. But now a new factor was introduced. SWMBO decreed a move of the system to a new location, which required putting the old HP computer on the concrete floor. Now when the BH man disconnected the UPS, the old HP computer case (with bare metal on the bottom of the case and no rubber pads), went to floating intermittent ground, and as a result a spike somewhere in the system caused the microprocessor to go NFW.--BH at first promised to recompense Mike for his computer, but upon review by a higher manager decided to disallow his claim because of "use of unrecommended equipment" which, oddly enough was not being used at the time. We soon gave up trying to penetrate the thorny BH hedgerow. SWMBO summoned "virtual money" out of the ether, and a cheap reconditioned computer was procured.--Upon being informed of these events, I proclaimed "FT". We then managed ,"hook or crook", to obtain green coated grounding wire, green wire nuts, grounding clamps, and ground pegs. I then proceeded to connect all grounds to each other every which way. On the inside walls I found an unconnected ground wire, "Bob's your uncle". The outside walls were original and there was no ground wire. So, I used a 1 foot drill bit to bull my way through the metal box and on through to the outside of the walls.--I then proceeded to interconnect all ground wires to the Progress Energy ground wire, the copper water pipes, and the ground pegs in a bewildering array. The network was so complex that no jake leg, shade tree electrician, or BH man would ever be able to figure out how to defeat it, let alone doing the work involved.--The end result had been that Mike has had no electrical failures whatsoever in two and half years. His "state of the art" washing machine, which used to require replacement of the microprocessor twice a year, now has no problems.--One would think the "maintenance contract" guys would check for ground, but apparently they work like government employees, and regard underlying problems as allies.--One of my other neighbors "Jesus", pronounced "Hey Zeus" as if one were addressing the "Father of Gods", has the same two wire cable to 3 pin sockets setup, I.E. no ground. In Jesus' case I installed a common UPS and ran the cable through it, obtaining a "jury rigged ground" Result? No problems whatsoever in the past two years.--After a suitable time for responses, I plan to forward this entire thread (redacted of names, identities and so forth) to the CEOs of BH and several UPS manufacturers.--I invite and welcome your comments. I particularly would like to hear stories of similar problems. Contraian remarks are always welcome, but I would prefer concrete assertions rather than derision and sarcasm. I freely admit I have been feeling in the dark, and trying in my humble way to follow what I have been told in this respected forum. Best RegardsClear Ether

author: PetrosA
author_rank: Frequent Contributor
timestamp: September 05, 2011, 04:34:45 am
content: Using the UPS to bond/establish the ground might work, but it can be a dangerous thing. Typically, the grounds would be bonded together at the ground rod with pretty hefty wires (size depending on what system they're bonding). Since the ground's main purpose is to drain surges, and the bond's main purpose is to redirect fault current back to the neutral, if you establish a ground at a UPS through the coax cable, then that small cable will carry any surges or fault currents which could get ugly when they get big (like from a lightning strike). The best, and probably cheapest option would be to run a new line to feed the PC and router.

author: SgtRock
author_rank: Unknown
timestamp: September 05, 2011, 06:02:36 am
content: Dear PetrosA:--I am completely in agreement with your remarks. Stealing ground from the cable company is only a "temporary, no money solution". If one has no ground at the socket and one routes the cable through the UPS, that is what obtains. Assuming an uneducated, and ungrounded customer with little or no money: Would you recommend using the Cable Company ground or not?"Three weeks in the lab will save you a day in the library every time" Stanley Williams, HP LabsBest RegardsClear Ether

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 12:29:22 pm
content: That is a very interesting story. It is hard to tell if the added grounding is effective in this case, but I respect the fact that you have tried to add grounding. Good move.I know it is circumstantial good fortune, but my current home (I posted elsewhere here) came with excellent grounded wiring and outlets.... C

author: PetrosA
author_rank: Frequent Contributor
timestamp: September 05, 2011, 05:03:58 pm
content: I can't recommend using the cable company's ground for grounding electrical devices. The most likely danger is that the cable guy will disconnect the cable outside somewhere and it will be carrying some current from the UPS. Cables have been known to burn up from being incorrectly connected to the electrical system as well. The cheapest solution is to run a single ground wire (min. 14 AWG) back from a grounded outlet to the nearest bonded cold water pipe or panel. The UPS needs a good ground to shunt surges, and the cable ground is simply not designed for that. I have seen ungrounded UPS's wreak havoc with PCs and other electronics when they don't have a ground.

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 05:30:38 pm
content: >>> I can't recommend using the cable company's ground for grounding electrical devices.I agree, but it may have been better than nothing in those circumstances.>>> The cheapest solution is to run a single ground wire (min. 14 AWG) back from a grounded outlet to the nearest bonded cold water pipe or panelI much agree with this, I suppose, because that is what I have seen all my life.Thank you for an informative post. .... C

author: ejeffrey
author_rank: Super Contributor
timestamp: September 05, 2011, 05:57:26 pm
content: The reason that attaching a ground lead to the cable companies ground pin is that it doesn't actually fulfill the goal of a ground conductor. The ground conductor needs to have a low impedance path back to the distribution transformer. The purpose of the safety ground is that if you get a live to chassis fault it will sink the fault current in order to blow the breaker.Attaching a ground wire from a socket to the cable ground does not satisfy this purpose adequately. If the cable ground has its own ground rod, you now have the earth in your fault path, a highly undesirable configuration. If the cable is bonded to the electrical ground rod you are better, but now the shielding of your coax is in the fault path which is still not optimal.Attaching to the cold water pipe is similarly not suitable. At least the cold water pipe should be properly bonded to the electrical ground, and provide a low impedance path for fault currents. However, if there is a problem with the grounding of your water pipes -- which can easily happen if a section of pipe is replaced with PVC, a fault can electrify your plumbing.Really I wouldn't recommend either of these plans under any circumstances, and they are certainly illegal. They both carry the risk of making an unrelated part of the house dangerous, or increase the risk of an electrical fault leading to a fire because a fault current goes through a high impedance link. It would be better to just leave the outlet ungrounded.The myth that it is OK to use a copper water pipe for grounding probably originates from many people seeing ground wires attached to their water pipes. This is actually required, but the purpose is to provide a ground connection to the water pipes -- the idea is that if a live wire touches the copper, it needs a low impedance path back to the transformer without going through the ground rod. The wire going to the copper pipe is *not* (in a to-code installation) providing a ground connection for the electrical system, and is certainly not providing an alternate ground connection for outlets that don't have 3 conductor wiring going back to the distribution panel.

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 06:15:27 pm
content: >>> Attaching to the cold water pipe is similarly not suitableWhen I have posted about "cold water pipe", I have referred to the water pipe inlet running through the ground into the basement through the concrete floor. I thought that was what PetrosA was referring to.Perhaps I misinterpret. However, using the cold water inlet as described is Code where I live and has been for decades.... C

author: ejeffrey
author_rank: Super Contributor
timestamp: September 05, 2011, 06:28:04 pm
content: It is required to attach the electrical ground from your main distribution panel to the water pipe coming out of the ground. The purpose of this is to make sure that your plumbing is grounded. I don't think it is allowed to use this as your physical earth connection -- that requires a dedicated ground rod. I could be wrong about this, or it could be allowed in some jurisdictions and not others. However, you can never use a copper pipe of any sort to provide a ground connection to an outlet in lieu of a wire running back to the ground conductor at your main breaker where it is connected to the neutral line of the transformer.

author: SgtRock
author_rank: Unknown
timestamp: September 05, 2011, 07:11:08 pm
content: Dear Ejeffery:--I completely agree with your remarks. I have only one small quibble; You stated:"Attaching a ground wire from a socket to the cable ground does not satisfy this purpose adequately."--I checked the thread carefully, and I cannot find this being advocated anywhere.--Imagine for a moment that you are a hapless resident of my neighborhood. You have a 1950s 2 wire (no ground) system. One day you buy a UPS. When you route the cable through the UPS the "No Ground" light stays off. When you do not route the cable through the UPS the "No Ground" light stays on. Assuming arguendo that you cannot call an electrician, what do you do? You have 3 choices; 1) Use the UPS and route the cable through it. 2) Use the UPS and do not route the cable through it. 3)Do not use UPS at all. What do you recommend?--BTW, in my neighborhood the BrightHouse cable ground is directly clamped to the Progress Energy ground wire at the meter box. When I was adding ground wires to my friend's house I tied everything back to that point, with some ground pegs and water pipes thrown in for good measure.--Thanks for the good advice. Your further comments are humbly solicited. Best RegardsClear Ether

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 07:43:08 pm
content: >>> It is required to attach the electrical ground from your main distribution panel to the water pipe coming out of the ground. The purpose of this is to make sure that your plumbing is grounded. I don't think it is allowed to use this as your physical earth connection -- that requires a dedicated ground rod. I could be wrong about this, or it could be allowed in some jurisdictions and not others.It is obviously dependent on jurisdiction. I have never had a separate ground rod in any of my residences. Thank you for your elaboration - I appreciated it. ... C

author: IanB
author_rank: Super Contributor
timestamp: September 05, 2011, 08:02:09 pm
content: Quote from: Computeruser on September 05, 2011, 07:43:08 pmThe ground rod is not really visible so you would not know if it was there. The reason it is not generally permitted to use the metal piping as a ground point is you cannot know if the pipe makes a good earth connection once it disappears from view. In my house, for example, the mains water supply arrives in a plastic pipe and gets converted to copper once it enters the building. Even if the buried pipe is made of copper it may be in a protective sheath for corrosion resistance.The ground, or earth, connection is usually provided by the electricity company or house builder at the junction box where electricity enters the premises and this earth has an assurance of being a good earth. This is the earth you should use for electrical safety.As was mentioned above all metal piping in the house should be bonded to the main earth provided at the junction box, but this does not mean the metal piping is the source of the ground, it means the metal piping is grounded for safety.

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 08:41:43 pm
content: >>> The ground rod is not really visible so you would not know if it was there. The reason it is not generally permitted to use the metal piping as a ground point is you cannot know if the pipe makes a good earth connection once it disappears from view.>>> In my house, for example, the mains water supply arrives in a plastic pipe and gets converted to copper once it enters the buildingThere really is lots of detail in all of this, isn't there?In my case, there may be a ground rod outside at the street, but the single and only ground wire at the panel in the basement connects to the incoming water pipe. I checked very carefully.I will soon get a chance to perhaps see what is outside because the city is going to replace the water distribution system. For certain, the large water pipes are plastic (or some composite). I should see the joins when they do this. We did have digging in the front (and back) yard to put in a sprinkler system and the company had diagrams and permissions for digging around water, gas and electrical conduit (all going out the front to the street).... C

author: ejeffrey
author_rank: Super Contributor
timestamp: September 05, 2011, 09:42:09 pm
content: Quote from: SgtRock on September 05, 2011, 07:11:08 pmIt doesn't matter much. All three cases you have equipment that expects a 3-pin power connection with a safety ground run on an ungrounded circuit. In one option you have fooled the UPS into turning off the warning light, but you haven't actually fixed the problem. As long as you aren't connecting the cable with the purpose of making the warning go out, that is probably fine. I understood that the cable was being connected in order to 'provide a ground' for the UPS circuit -- and this is what I was saying was not effective. Which one is safer depends on the details of the wiring and what type of faults you are trying to protect against.QuoteAs in the incoming power to your distribution panel has only three wires (two live wires plus neutral, but not ground)? Also, does your house have a separate main disconnect switch upstream of your distribution panel? It could be inside or outside your house near the meter.

author: Kibi
author_rank: Unknown
timestamp: September 05, 2011, 10:25:47 pm
content: We used to live in an old house many years ago. When I say old, I mean properly old, it has a three phase supply as that was no uncommon back in those days. The wiring had been updated in the 50's, so it had proper steel conduit in the walls and ceilings, with proper PVC insulated wires running through them, not that cotton mesh type insulation from the 30's. Circuit breakers hadn't been invented before the upgrade, so the distribution board was still equipped with those nasty porcelain fuse cartridges which you had to reset by wiring a new piece of fuse wire between the contacts.Anyway, the important thing to note is that even after the wiring had been "updated", the house was still supplied with three phase.There had been a problem with the electricity bill, ZESA (Zimbabwe Electricity Supply Authority) said we hadn't paid for 6 months when we had. Soon enough a representative of ZESA arrived and said that he had to cut our electricity supply off until we had paid the bill. I call him a representative, because this guy was by no means an electrician. He removed the four main fuses on their side of the meter and took them away with him saying that he's bring them back and re-fit them once our bill was settled.It took a couple of days to resolve our problem with ZESA's head office. The representative returned whilst nobody was at home to re-fit our fuses. He left a note to say he'd been round return our electricity supply.We returned home that evening, saw the note and switched the light on which glowed extremely brightly and then gave up after a few seconds. Mmmm, that's odd. Perhaps they are supplying us with extra electricity to make up for the time we spent in the dark.The joke was short lived as other lights either didn't switch on at all or suffered the same fate as the first one. The fridge was running, but didn't sound too good, so it was promptly switched off at which point the kitchen light came on.I pulled the lead out of the kettle and put my meter across it's terminals to find about 380v registering on the it.Right, off to distribution board I go. A quick inspection revealed that the ZESA representative had only replaced three of the fuses that he'd taken away. One fuse was present in each of the five feeds, but the fuse in the neutral line missing!!!Brilliant work, so now the whole house is floating.The low impedance water heaters on one phase are allowing the other higher impedance appliances like lights to conduct through them phase to phase via the neutral line which is floating.After going through all the bureaucracy and procedures of such government organisations that ZESA is based on, we managed to get hold of the representative who has re-fitted the fuses. He was quite flippant about the fact that he had misplaced the fourth fuse whilst they were in his possession and thought he was doing us a favour by at least giving us back three of the four. Aren't we the lucky ones!He got quite aggressive when I tried to explain the basic principals of electricity and the methods of it's transmission and that it would have been better to at least put one of the fuses on the neutral line and we could have put up with just two phases and a few sections of the house not working at all rather than potentially burn the house down.To compound the issue, he's lost one of the 60A fuses that goes on one of the live phases. The 120A neural fuse was inserted in a live feed!Oh well, at least we are lucky that nobody was hurt.

author: Computeruser
author_rank: Regular Contributor
timestamp: September 05, 2011, 10:43:55 pm
content: IanB wrote: The ground rod is not really visible so you would not know if it was thereejeffery wrote: As in the incoming power to your distribution panel has only three wires (two live wires plus neutral, but not ground)?On closer reflection and inspection, you are both correct. Thank you.Yes the three wires belong to the electric company, so the neutral is probably grounded somewhere where I cannot see it. Then there is a ground wire from the screw block on the input over to the water pipe coming out of the ground into my house.So I can see one ground, but I am now sure there is another one I cannot see.Thank you for all the information. ... C

author: ejeffrey
author_rank: Super Contributor
timestamp: September 07, 2011, 02:04:53 pm
content: QuoteYes, this is an all too common problem with 3-phase systems. Our laboratory had a problem where the jokers who call themselves electricians didn't screw down the neutral line to the main disconnect switch. It was very rigid, so it held against the contact by spring force, but eventually arced and heated until the copper became brittle and broke. All told we got off easy with only about 15,000 EUR worth of damages. Really, the neutral line should not be fused to begin with, and definitely shouldn't be fused in a 3-phase system exactly to reduce the chance of this sort of issue -- if it actually blows under normal operation it is more likely to leave the system less safe than before.

author: Bren
author_rank: Contributor
timestamp: September 07, 2011, 07:16:44 pm
content: Well, after reading all your posts, It sounds to me like an average occurrence of trying to deal with large scale electrical or telecommunication companies.You're better off banging your head against a wall.

author: SgtRock
author_rank: Unknown
timestamp: September 09, 2011, 08:17:29 am
content: Dear Ejeffery:--You stated:"It doesn't matter much. All three cases you have equipment that expects a 3-pin power connection with a safety ground run on an ungrounded circuit. In one option you have fooled the UPS into turning off the warning light, but you haven't actually fixed the problem."--The reason I temporarily used the UPS was not so I could make the "No Ground" on the UPS go out, It was so the computer equipment would have a ground. And indeed it did, at least enough to keep it from floating. The computer blew sometime after the "Cable Guy" disconnected the UPS. Admittedly the sheathing of the cable would not protect against a high amperage short."As long as you aren't connecting the cable with the purpose of making the warning go out, that is probably fine. I understood that the cable was being connected in order to 'provide a ground' for the UPS circuit -- and this is what I was saying was not effective. Which one is safer depends on the details of the wiring and what type of faults you are trying to protect against."--You seem to have taken the position that I should not do something (even temporarily), and also the position that it makes no difference if I do it or not. You seem to have lost track of the fact that I grounded all of my neighbors sockets as soon as I could, and instead answered as if I was advocating using the cable sheath ground as a first and permanent solution.--Let me restate my point, briefly. My neighborhood has 1950s houses, 2 wire runs, and often as not 3 hole sockets (hooked up by dern fools). Failures of equipment containing microprocessors are frequent because of the floating ground situtation. I merely mentioned my neighbor's case because I thought it interesting, and to provoke discussion. I was not recommending that people try to ground the entire house by using the cable sheath. Best RegardsClear Ether

author: saturation
author_rank: Super Contributor
timestamp: September 09, 2011, 12:20:36 pm
content: In the US, If you have an old house that still has old wiring and you own it, it would pay to rewire it professionally to electrical code rather than DIY.DIY is OK for a quick fix, but with surges and potential breaks in the neutral or ground lines due to storms or a bad branch circuit elsewhere or substandard wiring etc.,, the loss of your electronics or appliances often will cost more, not so much just to replace it, but the work you may be doing that require these appliances or the inconvenience of it.If you are buying an old house, have it inspected.

author: SgtRock
author_rank: Unknown
timestamp: September 09, 2011, 01:51:08 pm
content: Dear Saturation:--Very good advice. My neighbor is handicapped, and his wive is unemployed, so rewiring is out of the question. There are very few home owners in my neighborhood who can afford a full top to bottom rewire of their houses, right now.--As far a DIY goes, it is the only choice some folks have with regard to having a grounded outlet or not. Best RegardsClear Ether

author: saturation
author_rank: Super Contributor
timestamp: September 09, 2011, 03:37:39 pm
content: Hello SgtRock,I'm sure your help was much appreciated, in that case DIY is better than not getting it done. They must have lived there for a very along time; if they buy appliances like washer dryers, they have unusual plugs that will need to disassembled and adapted to pre-code wiring. Today, not only is the labor more costly, but the cost of copper wires has appreciated a lot both with the housing boom of the early 2000s and the consumption from China.Quote from: SgtRock on September 09, 2011, 01:51:08 pm