Ground problem? Help!


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Old 06-05-09, 01:00 AM
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Ground problem? Help!

Hi, new member here.
After touching a non painted area of my computer case the other day I received a nice JOLT. (Not static. Constant current as long as my hand remained in contact with case.) After disconnecting components to isolate the problem, came down to ONLY the power supply, everything else unhooked. Still getting shocked. I turned OFF the switch on the power supply itself and still getting shocked. (Power supply plugged in but not switched on) Decided to replace the power supply. After replacement I wasn't shocked by the case but decided to hook my new multimeter to an unpainted surface on the case and the negative lead to the floor (stabbing through the carpet to the concrete underneath). Reading is 50v-70v AC depending on which part of the floor I contact.
After planting my bare feet firmly into the carpet I tested with positive lead on bare case and negative lead against my skin. Same reading, about 60v AC. (This changes to about 20V if I lift my feet off the floor, but still seated in metal desk chair.) Decided to test my other computer which is plugged into a different outlet (same room) and got the same readings.


Decided to then test the outlets in the room. These are standard U.S. 110v 3-pronged outlets. The readings are as follows:

Hot to Neutral - 122.4v AC
Hot to Ground - 103.2v AC
Neutral to Ground - 13.2v AC

I noticed that if I plugged in a power strip (3-prong style,empty) and switched it on, the outlet readings changed to:

Hot to Neutral - 122.4v AC
Hot to Ground - 64.8v AC
Neutral to Ground - 51.4v AC

I noted that the 60v reading i get from the computer cases
to the floor seems to match the voltage readings I get from the outlet when a bare power strip is plugged into it and switched on.

Sorry for such a long post I just wanted to be thorough with my description.

I can do these simple tests but I am ignorant when it comes to home wiring. Do these readings indicate a ground problem in the house wiring? Are these readings normal? Time to call the electrician?

I live in a single story house on concrete slab, standard US 110v 3-prong outlets and a 220v in the garage. House was built in 1952, originally had a fuse box but updated with breaker box some years ago. Readings taken with a very nice $450 Snap-On multimeter calibration good.

Any advice is greatly appreciated.
 
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Old 06-05-09, 05:05 AM
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Hi Don, good meter, however always be cautious when using digital meters, as their high input impedance can give false readings when measuring voltages, called phantom readings. However, and I'm not one of the pros, it does sound like you have a ground problem.

The pros will be along to help you sort it out. Calling an electrician would be the safest way, but this is a diy board, so let us know how you feel about checking connections at various points throughout the house. Again, hold for the pros and good luck,

Bud
 
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Old 06-05-09, 07:56 AM
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Originally Posted by donkeyspam
The readings are as follows:
Could you do the same readings again with a regular lamp plugged in and turned on? Something like a 60W would be just fine.

standard US 110v 3-prong outlets...House was built in 1952
This is a little suspicious for possible grounding problem. Based on the age, 2 prong outlets would be more likely. Your readings with the power strip point towards an illegal replacement of 2 prongers with 3 prongers using a bootleg ground (I'm assuming the power strip has a pilot light in the switch). The lamp test will provide better evidence.

If you feel comfortable doing so, switch off the breaker, pull out the receptacle and let us know what wiring is there. Please note any insulation colors or bare and whether the wire is a cable or metal conduit or spiral metal, etc.
 
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Old 06-05-09, 12:16 PM
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Thank you (and new readings)

Thanks for the replies so far.

Could you do the same readings again with a regular lamp plugged in and turned on? Something like a 60W would be just fine.
I removed the power strip from the outlet and plugged in a table lamp with a standard 60W GE incandescent bulb.
The readings returned to about the same as the bare outlet with nothing plugged in.

Hot to Neutral - 122.4v AC
Hot to Ground - 103.2v AC
Neutral to Ground - 13.2v AC

Seems to be something about the power strip that causes the near 60 volt readings from Neutral to ground and hot to ground. Note - I have tried 3 different power strips and all cause the same readings on the outlet when switched on.

The 60v AC readings I get from the computer cases to the concrete still bug me.

This is a little suspicious for possible grounding problem. Based on the age, 2 prong outlets would be more likely.
Sorry I should have mentioned this before but I actually grew up in this very neighborhood. Next door in fact. These homes did indeed used to have 2-pronged outlets and a fuse box in the garage, however most people (about the early or mid 80s) had breaker boxes and 3-pronged outlets installed. Now as to whether or not the electricians who did the work installed proper grounds or not I really couldn't say. My knowledge of home wiring is about zero.

If you feel comfortable doing so, switch off the breaker, pull out the receptacle and let us know what wiring is there. Please note any insulation colors or bare and whether the wire is a cable or metal conduit or spiral metal, etc.
I'd hate to do that since I am not at all knowledgeable about home wiring. Terrifies me in fact lol.

Thanks again for the replies so far!
 
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Old 06-05-09, 12:27 PM
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Originally Posted by donkeyspam
The 60v AC readings I get from the computer cases to the concrete still bug me.
The 60V readings are a little tough to interpret because of a phenomenon with digital meters called "phantom voltage". The 13V between neutral and ground under a small load is not normal.

I'd hate to do that since I am not at all knowledgeable about home wiring. Terrifies me in fact lol.
No problem with that! I do recommend that you have an electrician check this out. Grounding problems can cause significant hazards around the home, so bringing in a pro to check it out would be a good idea. You've already noticed troublesome symptoms, and based on your initial observations, I do think there's something that needs to be fixed.
 
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Old 06-05-09, 01:49 PM
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Since you felt the current, you were probably better grounded than the PC, could you do some readings between a metal part as a pipe, or som other metal exept for the conduit and the 3 wires. It will be easier to get good readings with that lamp on.

In the meantime you will probably be more safe using a 2 wire ungrounded extention to your PC.

dsk
 
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Old 06-05-09, 02:15 PM
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Out of curiosity, is there a UPS anywhere in this mix?
 
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Old 06-05-09, 02:18 PM
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Hi there. Interesting problem you have. I'm guessing because the age of your house that if it has'nt been rewired it is probably a nob and tube job. If it is it is very likely that you have a back feed problem on your neutral causing the unwanted voltage. Have you checked to see if your electrical panels neutral and ground bars truly have an earth ground, meaning that they actually are connected to a ground rod and or cold water copper or iron pipe? I would do some checking and make sure that you have a proper ground. If you don't find one then you need to run a ground from your panel to an eight foot ground rod driven completely into the soil outside even better would be to run a ground wire to a cold water pipe. If this does'nt fix the problem you might want to consider installing an isolated ground sub panel. An islolated ground panel has its very own ground buss conected to its very own earth ground. These are commonly usedin new construction in offices and hospitals where lots of sensitive electronic equipment is being used. There is no special features to an isolated ground panel, its just a regular load center that has is own ground and does not run anything but sensitive equipment. I hope you don't have to go the extreme of having to install a new panel. I bet if you check to make sure your existing panel is grounded properly it will fix your problem. I hope this helps. Good luck!
 
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Old 06-05-09, 02:33 PM
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Originally Posted by journeyman ken
Hi there. Interesting problem you have. I'm guessing because the age of your house that if it has'nt been rewired it is probably a nob and tube job. If it is it is very likely that you have a back feed problem on your neutral causing the unwanted voltage. Have you checked to see if your electrical panels neutral and ground bars truly have an earth ground, meaning that they actually are connected to a ground rod and or cold water copper or iron pipe? I would do some checking and make sure that you have a proper ground. If you don't find one then you need to run a ground from your panel to an eight foot ground rod driven completely into the soil outside even better would be to run a ground wire to a cold water pipe. If this does'nt fix the problem you might want to consider installing an isolated ground sub panel. An islolated ground panel has its very own ground buss conected to its very own earth ground. These are commonly usedin new construction in offices and hospitals where lots of sensitive electronic equipment is being used. There is no special features to an isolated ground panel, its just a regular load center that has is own ground and does not run anything but sensitive equipment. I hope you don't have to go the extreme of having to install a new panel. I bet if you check to make sure your existing panel is grounded properly it will fix your problem. I hope this helps. Good luck!
I forgot to mention what back feed on a neutral is. Whenever you run anything on electricity it does'nt use all of the power you put into it so that extra power has to go somewhere, and that somewhere should be to a ground. If there is not an effective ground to the system then all of this leftover power has no where to go. So it continues to flow through the neutral system searching for anyplace it can be used or to a ground and safely diminished. (in your case it is probably flowing back through your neutral in the computer plug.) This leftover power shocks you because it has voltage on it, but it will not cause your breaker or fuse to blow or trip because this leftover power is not going through the "Hot" side of the system therefore is not running through any circuit protection such as a breaker. Imagine losing the neutral from the service drop to your house from the utility company. If this happens and it sometimes does everything in your house that is plugged in and in running would have no where to dump the leftover power and you would have a major problem on your hands since your entire system would be full of leftover power eventually causing all the neutrals in the house to have 120V therefore causing 240V at outlets where 120V should be. I am willing to bet that you probably go through a bunch of light bulbs at your house due to that extra voltage that has no way to escape.
 
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Old 06-05-09, 02:40 PM
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Thanks again for replies

Thanks again for the replies so far!

Out of curiosity, is there a UPS anywhere in this mix?
No, nothing like that. Computers are plugged straight into the outlets or through standard 3 prong power strips.

Someone mentioned the fact that digital meters can produce false readings or "phantom voltage". After reading more about this I decided to just go buy a 3-prong outlet tester from the hardware store to check for good ground. Probably the best way to be sure??? I did read something about it being common to read 60-80v "phantom voltage" when testing near 110v circuits (any disagreements??) so the 3-prong outlet tester seems like the best way to go. Can't argue for only $6.99

If after testing the outlets in the house the tester shows bad ground I will try to visually inspect the breaker box for an earth ground to pipes or something similar. If it looks like there's no ground I'll call an electrician out and have him look things over.

If someone has indeed simply tied the grounds from the 3- prong outlets to the neutral wire (creating a "false" ground) what would be the options? Would there be anything I could have done short of ripping into the walls and running ground wire through the whole house? (am in no financial situation to pay for something like that) Are there cheaper ways to earth ground the outlets safely?

Thanks again!
 
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Old 06-05-09, 04:01 PM
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Update

UPDATE:

Just went through the house testing each outlet with a 3-prong outlet tester from the hardware store.

All outlets in the house except for 2 indicate open ground.

About the 2 "Normal" outlets: One is in the kitchen where our 110v electric oven is plugged in. The other is on the opposite side of that wall in a small area where the water softener/water heater/gas furnace are located. Inside that wall and between the two outlets is where all the water pipes come into the house so I'm guessing they just grounded those 2 outlets to the pipes since they were close by. There are probably not even ground wires run from the breaker box throughout the house and no earth ground attached to the breaker box.

Sound about right? (I'll remove a few of the outlets to make sure but I doubt there are even ground wires run for them.)

If this is the case what would be the cheapest route for making the house safe? It's a 1 Story home on a concrete slab with circuit breakers. Box located in attached garage.
 
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Old 06-05-09, 05:04 PM
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If this is the case what would be the cheapest route for making the house safe? It's a 1 Story home on a concrete slab with circuit breakers. Box located in attached garage.
You have two options:

Replace any three prong outlets that are not grounded with ungrounded receptacles (two prong).

The safer solution though is to provide GFCI protection for any three prong receptacle. That doesn't provide grounding but makes them safer. You can either use a GFCI breaker or a GFCI receptacle at the beginning of the run or individual GFCI receptacles. The receptacles must be marked no equipment ground.
 
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Old 06-05-09, 05:25 PM
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As you've probably noticed, there are a lot of devices that don't use 3-prong plugs, lamps, TV, etc. You may want to consider running a few new grounded circuits to the key areas that you need good grounds - like your computer. It's usually about the same amount of work to run a single ground wire as it is to add a whole new receptacle.
 
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Old 06-05-09, 05:41 PM
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Originally Posted by journeyman ken
I forgot to mention what back feed on a neutral is. Whenever you run anything on electricity it does'nt use all of the power you put into it so that extra power has to go somewhere, and that somewhere should be to a ground. If there is not an effective ground to the system then all of this leftover power has no where to go. So it continues to flow through the neutral system searching for anyplace it can be used or to a ground and safely diminished. (in your case it is probably flowing back through your neutral in the computer plug.) This leftover power shocks you because it has voltage on it, but it will not cause your breaker or fuse to blow or trip because this leftover power is not going through the "Hot" side of the system therefore is not running through any circuit protection such as a breaker.
WHAT? I have never read anything so ridiculous in my entire life. Where did you get your electrical training?
 
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Old 06-05-09, 05:52 PM
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I thought it was just me but now someone else sees it so maybe I am not going crazy. Thanks furd.
 
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Old 06-05-09, 06:07 PM
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Was just about to ask, WHAT! but see the pros beat me to it so I may not need to relearn electric theory after all.
 
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Old 06-05-09, 06:41 PM
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Ok a few more questions.

Thanks again folks you've been very helpful. A few more questions if you don't mind.

1.) If my computer would have been plugged into a GFCI outlet and my power supply had shorted to it's shell, energizing my whole computer case, (as it apparently did) then would the breaker in the GFCI outlet have tripped saving me the shock? (I know this might sound stupid but keep in mind I'm a serious newbie here lol.) In other words it would act much the same as if the outlet were properly earth grounded?

2.) Is there a way to put some kind of GFCI breaker out in the garage next to the main breaker box that would cover the whole house? Or is it better to do the outlets individually? If it were you, which would you do?

3.) What's the best AMP rating for m whether I use a breaker or receptacles? I have 3 computers in the house, 110v Fridge, Dryer, Washer, Water Heater, Furnace etc. 3 Bedroom 1 level house. (Saw a lot of 10 GFCI receptacles, 20 AMP made by Smart-Lock? Says made to 2006 standards as opposed to older 2003 standards, whatever that means. Sound ok?


As you've probably noticed, there are a lot of devices that don't use 3-prong plugs, lamps, TV, etc. You may want to consider running a few new grounded circuits to the key areas that you need good grounds - like your computer. It's usually about the same amount of work to run a single ground wire as it is to add a whole new receptacle.
Not sure how to do this? Would you mean something like attaching a ground wire to the proper place on each of the outlets here in the bedroom then running them through a hole in the wall to the backyard and driving in a grounding rod or something?

And just out of curiosity:
Replace any three prong outlets that are not grounded with ungrounded receptacles (two prong).
What would be the reason for doing that? Simply so a 3-pronged appliance can't be plugged into it? Apologies, I am learning here. Why indeed do some appliances use 2-prong and some 3? As someone stated earlier many lamps, TV's etc. use 2-prong. Yet these items carry big voltage so why would it not be best to have them grounded? Anyone mind explaining this to a layman?

Thanks again, I hope ya don't mind so many questions this is all very interesting and I'm learning alot.
 

Last edited by donkeyspam; 06-05-09 at 07:00 PM.
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Old 06-05-09, 07:09 PM
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1) Probably not. A GFCI compares the current flowing on the "hot" and neutral wires and removes power if the imbalance is more than 6/1000 of an ampere. Since the GFCI in your scenario did not have a ground connection for the computer case there would have been no current imbalance to cause the GFCI to trip.

2) Not on a practical level. If you can find the first receptacle in each circuit the replacement of this receptacle with a GFCI model would be the cheapest and easiest. Generally speaking GFCI receptacles are about 1/3 the price of GFCI circuit breakers. If you have an older circuit breaker panel it is possible that GFCI circuit breakers are not even available.

I prefer to use the entire term, "equipment grounding" rather than just "grounding. My reasoning is that it removes the ambiguity of running a wire to a ground stake from any particular receptacle or point of usage. The PRIMARY reason for the equipment grounding conductor is to present a low-impedance (low resistance) path for FAULT current to return to the source (circuit breaker panel) and this allows a high enough current to flow to cause the branch circuit breaker to trip. Merely running a wire to a ground stake will NOT be the same as running the proper equipment grounding conductor back to the panel.

The reason for not allowing grounding-type receptacles on a circuit that does not supply the equipment grounding conductor is to remove the false sense of safety provided by a properly grounded circuit.

The main reason why many appliances do not have equipment grounding is that it has been determined by testing that the chance of a fault in the appliance causing a hazard to the user is minimal or non-existent. Often these appliances will have a case constructed from non-conductive material.
 
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Old 06-05-09, 08:15 PM
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Thanks Furd!

Hi Furd Beer 4U2 thx for the help.

I was wondering about one thing though. When asking about whether the GFCI outlet would have saved me from the shock you said you didn't think so. Just after reading your post I came across a page that discussed such a scenario and whoever wrote it seemed to think differently. Don't take me wrong I do appreciate the help, was just puzzled by it. Would you mind taking a quick look at the page and telling me what you think? Quite possible the person who wrote the page is wrong but I wanted your opinion on it.

It's the second to last paragraph near the bottom of the page.
Handyman USA - Adding a ground to your outlets

Let me know what you think.

Thanks!
 
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Old 06-05-09, 08:32 PM
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The GFCI would not trip till you provided a ground. In other words the energized case would not trip the GFCI because there would be no current to ground creating a difference in current flow between neutral and hot. The GFCI would protect you but first you have to provide the path that splits the flow of the neutral current partly to ground..

P.S. A modern computer ATX power supply is always on even if the computer is off. There is a power switch in the back of some power supplies that does cut them off but that is seldom used. The front button doesn't completely turn it off.
 
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Old 06-05-09, 08:47 PM
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Originally Posted by furd
1) Probably not. A GFCI compares the current flowing on the "hot" and neutral wires and removes power if the imbalance is more than 6/1000 of an ampere. Since the GFCI in your scenario did not have a ground connection for the computer case there would have been no current imbalance to cause the GFCI to trip.

.
the first part is true but the trip situation may not be, depending on circuit resistances in various sections of the circuit.

remember, OP was getting shocked.

If OP provided a ground source (which he did when he was getting shocked or testing with the voltmeter, there would be an imbalance and whether the GFCI would trip or not would be determined by the resistance in his new branch and how much current would flow through it. If it surpassed the 6 mA, it would trip. If not, it would simply continue to tingle.

donkey: if the current was in excess of 6 mA, you would have an initial shock but the GFCI would trip (and so quickly the shock would be nearly imperceptable). If the current were below the 6 mA threshold, the shock would continue indenfinately.
 
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Old 06-05-09, 09:10 PM
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Originally Posted by journeyman ken
... due to that extra voltage that has no way to escape.
WOW!

You mean if I keep that extra voltage from escaping then I can keep it around in my wires and not have to purchase more electricity? What a great money-saving concept!

willis
 

Last edited by williswires; 06-05-09 at 09:16 PM. Reason: removed a cynical remark
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Old 06-05-09, 09:26 PM
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Donkey, Ray and Nap answered your question as to if you had a GFCI receptacle would you have been protected from receiving a shock from your computer case. I had written my previous response from the standpoint of whether or not the GFCI would trip just from having the power supply fault to the case.

So to state it in entirety, the GFCI would not trip from the fault to case IF no grounded conductor to the case exists; HOWEVER the GFCI most likely would trip when you touched the case IF the impedance (resistance) between your finger and the concrete floor under the carpet were low enough to allow a current greater than six milliamperes (6/1000 of an ampere) to flow from your finger to the floor.

Thanks to Ray and Nap for keeping me honest.
 
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Old 06-05-09, 11:25 PM
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Furd you were absolutely right

Actually Furd that was my fault. Both you AND the page I linked are correct. What I really should have asked was "would the CFGI save my life?" That's really the concern here. I see what you meant by it not stopping me from being shocked and also not tripping just because the case became energized. I could indeed be shocked but it would most likely trip long before I received a dangerous jolt.
Bad wording on my part and my not fully understanding what I was reading.

P.S. A modern computer ATX power supply is always on even if the computer is off. There is a power switch in the back of some power supplies that does cut them off but that is seldom used. The front button doesn't completely turn it off.
Indeed you're right Ray. In this instance however I had the power supply switched off but was still getting jolted. In fact the jolt seemed more intense when the supply was switched off and less so when on. Does that put a new twist on things or do you think it still could have been the power supply? This worries me a little. I suppose the short could have been right between the switch and the power supply's male prongs? They are only about a half inch apart but possible. I was also thinking since the power supply was pretty caked with lint and dust on some internal parts that maybe there was just enough moisture in the grime to allow the short. I did try a different cord and still got shocked so I'm sure that wasn't it.

I am also still getting that 60v AC reading from either of my computer cases to the floor. Could be phantom voltage from what I read but I'll try to get a hold of an analog meter and re-check it to be sure.

Computer diagnosis/repair/networking is actually my field but you might be surprised at how LITTLE guys like me know about electricity. Diagnosing software problems, fried video cards and IRQ conflicts doesn't take more than an extremely basic knowledge of this stuff. I wish I knew more. This forum seems like a great place to start.
 

Last edited by donkeyspam; 06-05-09 at 11:51 PM.
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Old 06-05-09, 11:48 PM
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Originally Posted by journeyman ken
I forgot to mention what back feed on a neutral is. Whenever you run anything on electricity it does'nt use all of the power you put into it so that extra power has to go somewhere, and that somewhere should be to a ground. If there is not an effective ground to the system then all of this leftover power has no where to go. So it continues to flow through the neutral system searching for anyplace it can be used or to a ground and safely diminished. (in your case it is probably flowing back through your neutral in the computer plug.) This leftover power shocks you because it has voltage on it, but it will not cause your breaker or fuse to blow or trip because this leftover power is not going through the "Hot" side of the system therefore is not running through any circuit protection such as a breaker. Imagine losing the neutral from the service drop to your house from the utility company. If this happens and it sometimes does everything in your house that is plugged in and in running would have no where to dump the leftover power and you would have a major problem on your hands since your entire system would be full of leftover power eventually causing all the neutrals in the house to have 120V therefore causing 240V at outlets where 120V should be. I am willing to bet that you probably go through a bunch of light bulbs at your house due to that extra voltage that has no way to escape.

I hate to be rude in here but what you try to get the point here and where ya go thru this one { I have to double check and ran this fourm in French to double check my grammer due French is my primary langunge }

Right now the OP do not have issue with netural supply right now.

Merci,Marc
 
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Old 06-06-09, 12:06 AM
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Donkeyspam;

I do not know if someone mention or not., if so that fine but if not here little more details here.,

If you are comfortable with standard resdential system ? if so read on .,

What you should do now is turn off the fuse or breaker to that receptale and pull the receptale out BUT DO NOT disconnect any conductors { wires } at all just look at the black and white conductors to see they are in proper location { Brass screws are for hot conductors while siliver or white screws are for netual {white } conductors }

However a little twist here check the grounding conductor aka ground wire or earth wire it will be either bare or green.

If you have them are they termatied properly and if the box is metal that must be bonded properly if plastic box then skip that part but the recpectale grounding conductor must be there.

If they are look good look at the load centre { breaker box or fuse box } just watch for any loose conductors on bussbar if they are good and tight However one stern warning here .,, do not touch the main conductors from the meter they are engerized all the time unless you have main breaker outside below the meter socket.

If you have city water in your system check the ground clamp if they are corroded or got gunk build up WARNING be extra carefull there it may have current running thru there if you disconnect that it may nail ya { shock } and also check for ground rods if you can find them { they are useally near the meter socket area so you can't miss them } check them to make sure they are good and tight.

I know alot of older home with old style NM's some case they don't have grounding conductor in there so that something you have to watch out on that part.

I hope this will help you with few details if this don't help you or feel not too confortbale let us know.





Merci,Marc
 
  #27  
Old 06-06-09, 01:28 AM
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It may be hard to find such an failure. Connect the 60 w bulb between ground and neutral, and metering the voltage over the lamp.
Watch whats happening when you are turning on/off different loads in the house, wathsh when the frig or other things turns ot selves on and off.

Depending on the result it may be discovered, bad grounding, mix of wires, loose connection between neutral and ground.

It seems defenitly like the ground is not grounded properly.

If you have an open ground and one of the filters in the powersupply has an unbalance, this may be the fault.

dsk
 
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Old 06-06-09, 02:24 AM
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Thanks DSK and French.

I don't have grounds at all on most of the outlets. The house was built in 1952 with a fuse box and 2 wire outlets. Sometime in the 80s the fuse box was replaced with a breaker box and 3-wire outlets installed but the 3rd wire (ground wire) was never run. I'm sure alot of the houses in my neighborhood are like this. I discovered that 2 of the outlets in the house that run bigger appliances (electic oven, water heater, furnace etc.) are individually earth grounded. These outlets are very near the iron water pipes and someone has run a ground wire from each of those 2 outlets down to the pipes.

The other outlets have ground wires on them but I think they are just tied to the neutral wire. (nice huh)
 
  #29  
Old 06-06-09, 04:38 AM
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Originally Posted by donkeyspam
Thanks DSK and French.

I don't have grounds at all on most of the outlets. The house was built in 1952 with a fuse box and 2 wire outlets. Sometime in the 80s the fuse box was replaced with a breaker box and 3-wire outlets installed but the 3rd wire (ground wire) was never run. I'm sure alot of the houses in my neighborhood are like this. I discovered that 2 of the outlets in the house that run bigger appliances (electic oven, water heater, furnace etc.) are individually earth grounded. These outlets are very near the iron water pipes and someone has run a ground wire from each of those 2 outlets down to the pipes.

The other outlets have ground wires on them but I think they are just tied to the neutral wire. (nice huh)
We have simular traditions in older houses here, usually it works well, but if you have an error causing current to ground, the local ground voltage may differ from whats natural. You or one of your neighbours may have such an error. If you may find that error you may get rid of tthe problem, if it is in another house....

Try to turn off your mains switch, and still may feel meter voltage difference (more tan 15 V) between ground and neutral, or neutral and ground and your flor (let the PC remain plugged in even when power is of) the eroor is definitly on the other side of your main sw. Plug out the equipment plugged into the outlets bonded to the pipes, keep an eye on the meter, and lamp; ten plug in one by one, and turn it on/off.

If you have no real ground you may make a false ground potensial. Connect the ground terminal thru a 2.2 megaohms resistor to everything you may touch at the same time as you touch metal parts of your computer system to give you a feeling of electricity.(e.g. flor (wire or metallic net/plate under a mat frames on furniture etc.) the This wil discharge capacitive charged items, but prevent hazardious currents.

The powerstrips grounding connector may perfectly make a protective bonding between the different pc components, printer etc.

Those outlets who has common ground and neutral may work well, if the wire is huge, and short, and its not far to a connection between neutral, and ground.
Usually this may be harmful, espesially when huge loads are used, the voltagedrop in the cabel will equal the voltage between real ground and cabinet of the equipment.
I would say the local grounding to the piping is acceptable, but not good. The use of neutral to the ground pin will give a sudden protection if you get an error on that equipment, but it may also give you a shock caused by a fault in other locations. For a normal helty person, this wil feel uncomfortable, but not be a great danger. If you hav hart trouble....???

dsk
 
  #30  
Old 06-06-09, 02:18 PM
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To the one who called my reply post rediculous, I'd like to ask where you got your electrical training. Sir I am a licensed electrician I gave this person advice based on similar issues I have troubleshooted and repaired in the field many, many times. I have seen the effects of an open neutral and many times its not a pretty site. The original poster mentioned that the major appliances in his home had there very own earth ground. I am willing to bet that if he were to disconnect these grounds to these appliances that they to would be shocking him since ranges are all metal they make an excellent receptor to unwanted voltage looking for a path to ground. As a matter of fact I had a service call a while back that this just happened to be the issue. The little old lady said t her range shocked her hard everytime she touched it, being an old house it did'nt take long to find the problem. ZERO grounds. And all the backfeed off the nuetrals was present on the metal range and everytime she touched it(usually with bare feet) she made a path to groung(not a good one mind you) but still a path and it was just enough path for her to feel the shock. I have not made any rude comments to anyone on this forum and I do not intend to, but sir maybe educate yourself a little more next time before you call a perfectly logical answer rediculous.
 
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Old 06-06-09, 02:53 PM
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Oh yeah furd, lets not help the guy fix the problem, lets just put a GFCI in as a band aid and pretend it went away.
 
  #32  
Old 06-06-09, 02:56 PM
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Originally Posted by journeyman ken
Oh yeah furd, lets not help the guy fix the problem, lets just put a GFCI in as a band aid and pretend it went away.

Um, ken, that is an accepted method per the NEC. You have problems with the NEC? They publish the committee address in every copy. Write them.

and so much for not making rude comments to others ken.
 
  #33  
Old 06-06-09, 03:11 PM
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I was going to bite my tongue and let the mods take care of you, Ken, but since you want to raise a stink, I'm not going to bite myself that hard.

Originally Posted by journeyman ken
Hi there. Interesting problem you have. I'm guessing because the age of your house that if it has'nt been rewired it is probably a nob and tube job.
just for correctness, it is Knob and tube.

If it is it is very likely that you have a back feed problem on your neutral causing the unwanted voltage
.unwanted voltage? POCO only supplies you with 120/240. I think we want all of that.

Have you checked to see if your electrical panels neutral and ground bars truly have an earth ground, meaning that they actually are connected to a ground rod and or cold water copper or iron pipe
?and you believe this causes a problem with voltage on the ground or some sort of feedback. I question your training Ken.

I would do some checking and make sure that you have a proper ground. If you don't find one then you need to run a ground from your panel to an eight foot ground rod driven completely into the soil outside even better would be to run a ground wire to a cold water pipe.
Ken, you really want to look at section 250 of the NEC. Better, in your claim, is not correct. Both connections would be correct and better.

If this does'nt fix the problem you might want to consider installing an isolated ground sub panel. An islolated ground panel has its very own ground buss conected to its very own earth ground.
What??? what a load of hooey. All neutrals and EGC's are bonded to the same electrode system. That is code.


These are commonly usedin new construction in offices and hospitals where lots of sensitive electronic equipment is being used
.Yep, just like the 600k+ sq foot hospital I am working on right now.

There is no special features to an isolated ground panel, its just a regular load center that has is own ground and does not run anything but sensitive equipment
again, you are very wrong. An iso ground system actually has TWO EGC's. You have the common EGC for connections to all equipment bonds and then you have the iso ground for the power system to the appliances. There is a huge difference between an iso ground panel and a standard panel,. The iso ground panel has a typical ground connection PLUS is has an isolated grounding conductor terminal that is isolated electrically from the panel. and components.

. I hope you don't have to go the extreme of having to install a new panel. I bet if you check to make sure your existing panel is grounded properly it will fix your problem. I hope this helps. Good luck!
He doesn't have an EGC to the recep Ken. He has a bootleg ground so the EGC is electrically connected to the neutral.


I forgot to mention what back feed on a neutral is. Whenever you run anything on electricity it does'nt use all of the power you put into it so that extra power has to go somewhere, and that somewhere should be to a ground
.WOW! you have extra power running around? Don't let the POCO hear about this. They will want to charge you for it.


If there is not an effective ground to the system then all of this leftover power has no where to go.
again, leftover power. Maybe I can save it for a rainy day.

So it continues to flow through the neutral system searching for anyplace it can be used or to a ground and safely diminished. (in your case it is probably flowing back through your neutral in the computer plug.) This leftover power shocks you because it has voltage on it, but it will not cause your breaker or fuse to blow or trip because this leftover power is not going through the "Hot" side of the system therefore is not running through any circuit protection such as a breaker. Imagine losing the neutral from the service drop to your house from the utility company. If this happens and it sometimes does everything in your house that is plugged in and in running would have no where to dump the leftover power and you would have a major problem on your hands since your entire system would be full of leftover power eventually causing all the neutrals in the house to have 120V therefore causing 240V at outlets where 120V should be. I am willing to bet that you probably go through a bunch of light bulbs at your house due to that extra voltage that has no way to escape.
I'm sorry but I am laughing so hard I cannot continue to dissect your post and point out all the incorrect statements.

I don't know where you got your training Ken but I heard Kelloggs recalled all the electrical licenses they put in the cereal boxes. It was all a joke but some folks took them seriously. I think your name is on the list Ken.


Mods; if you want to edit or delete my post, I understand but please do something about Ken. He obviously has no comprehension of electrical systems and could be the cause of somebody getting hurt if this thread is indicative of his assistance.
 
  #34  
Old 06-06-09, 03:32 PM
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You guys have some serious issues. You guys should rethink giving people electrical advice. The GFCI band aid problem, sorry you are wrong thats only approved if you are simply wanting to change out receps where an equipment groung is not present in the box. Not when there is obviously a more serious problem a hand that needs to be addressed. And uh nap is it? You obviously have no idea what you are talking about. First of all, sir you have obviously never been bitten by a neutral that had back feed on it "ouch" it does'nt feel to good. I'm not going to waste any more of my time battling wits with you, because it would be an unfair fight. Especially since the only ammo you have is taking the advice I give and twisting it around out of context and making a fool out of yourself. I joined this forum hoping to learn a little, maybe make some friends and hopefully help out a few people, but if I am going to have to put up with people such as you two guys then I think maybe this site is not all its cracked up to be. I admit I have ran across a few people on here who do give some good advice I appreciate intelligent conversation and I will miss them but its not worth having my intelligence insulted by a couple of ignorant fools. Good bye you can have this useless forum. I just feel sorry for the people who need good advice on here and have to filter the good advice from the bad on there own.
 
  #35  
Old 06-06-09, 03:43 PM
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new question

Hi again folks!

Have talked to the electrician (came highly recommended) and he says he has done tons of work over the years in my neighborhood. All these houses have the same floor plan and the same wiring (originally anyway). He says that without even being here he's 99 percent sure that the breaker box and 3-prong outlets were simply installed without running a ground wire. Ground wires on the outlets tied to the neutrals. He also confirmed my thinking that someone earth grounded the 2 individual outlets near the water pipes that run the major appliances. Says he's seen it a thousand times on these houses.

Anyway I explained to him that money was very tight and there's no way I could pay to have a ground wire run throughout the house. He said he'd come over and first make certain this was the problem and check for any other problems and if so, he'd install GFCI receptacles where appropriate.

He did explain to me the fact that the GFCI doesn't provide any kind of equipment ground and that my sensitive stuff (like the computers) wouldn't be protected by surge protectors but that at LEAST they would help prevent myself or family getting knocked senseless by a shorted appliance. That's just all I can afford to do right now and safety is the main issue.

What I forgot to ask him and what I would like to ask of you guys is this:

If I attached a ground wire to each of the (2 or 3) outlets where I plug in my computer equipment and run those ground wires outside to a grounding rod or even over to the water pipes (like the 2 outlets in the kitchen) would this allow my surge protectors to do their jobs? I would still have the GFCI receptacle installed on the circuit but would an earth ground for a few of the outlets as described help save my computers?
would this be ineffective or even dangerous not running the ground all the way back to the panel?

Thx in advance!
 
  #36  
Old 06-06-09, 03:51 PM
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ya, the problem is the bootleg ground. That needs to be rectified and the GFCI installed.

we already told the OP that there is an improper grounding system in the situation. I took that it was obvious that would need to be remedied.

And uh nap is it? You obviously have no idea what you are talking about
if you say so kellogg ken.

First of all, sir you have obviously never been bitten by a neutral that had back feed on it "ouch" it does'nt feel to good
.I am embarrassed to admit how many times I have been bitten. I was seriously injured through the fault of an idiot that crossed neutrals which resulted in me getting 277 volts directly across my chest. Not been shocked, ya, whatever.

I'm not going to waste any more of my time battling wits with you, because it would be an unfair fight.
You are correct. You would lose.

Especially since the only ammo you have is taking the advice I give and twisting it around out of context and making a fool out of yourself.
I twisted nothing around. I quoted you. You have made the fool of yourself on your first outing here. You should be proud of yourself...because nobody else is.

I joined this forum hoping to learn a little,
well, if your read this thread, you should have learned a lot. If you have failed to, all I can say is there must be a disability you deal with that we cannot help you with.

hopefully help out a few people,
Sorry Ken but if this has been indicative of your help, I would consider typing in white.

I admit I have ran across a few people on here who do give some good advice I appreciate intelligent conversation and I will miss them but its not worth having my intelligence insulted by a couple of ignorant fools
then I would suggest refraining from having a conversation with yourself. You will be sadly dissappointed.

I just feel sorry for the people who need good advice on here and have to filter the good advice from the bad on there own.

Well, with you leaving Ken, that job just got a lot easier.


Sorry if it looked like this was addressed to you Donkey. It wasn't.
 
  #37  
Old 06-06-09, 04:07 PM
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I will lock this thread tempory until myself and other modeators discuss the issue,


Donkeyspam.,
Please bear with us for a moment until few situation is resloved.


Sorry about that.

Merci,Marc
 
  #38  
Old 06-06-09, 09:14 PM
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I am going to unlock the thread now but please keep it civil in here.

Merci,Marc
 
  #39  
Old 06-06-09, 09:23 PM
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Sure enough Marc.


so, donkey. If you are still around let us know. You are kind of right on the EGC install but there are rules to follow and possibly a few other things you need to take care of as well.
 
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Old 06-06-09, 09:44 PM
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Still around and thx

Sure I'm still around and I appreciate your continuing interest!

What would be the best way to ground those few outlets in your opinion?

By the way I was bored today and took my power strips, multimeter and outlet tester around the house checking all the other outlets and noting some stuff that was odd to me. Was hoping you could shed some light.

1.) Each of my power strips has a light showing it's ON. They also have a second light indicating "Protection On". I'm assuming second light means it has found proper ground and surge protection is working.
Anyway when I plug a power strip into one of my many non-grounded outlets the strip becomes powered but the Protection light stays off (as expected). However if I plug my 3-prong outlet tester into the plug-in above it (on the same outlet) the Protection light comes on as if it's got a ground.
Just curious to know what causes that to happen.

2.) Also was wondering why the multimeter shows 122v from Hot to Neutral (on the other plug-in, same outlet) when the power strip switch is OFF but then when it's switched ON the readings change to 60v Hot to Neutral and 60v Hot to Ground. Is this a normal side effect of someone having tied the Ground wire to the Neutral wire or is it the mechanics of the power strip that causes this?

The 2 outlets on the kitchen wall grounded to the water pipes are the only outlets that don't show this behavior. Was just curious as to the science behind that.

Thanks for reopening the thread by the way.Beer 4U2
 
 

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