What amount of voltage do you measure do you measure to the floor? Is it still there if you turn of the computer?
Does your meter measure frequency too (some do)?
When you use rew and touch the case, what noises are gone? The voltage to the cement floor?
You really need to know if the computer case is ground and what the actual voltage to earth ground is. Get a long wire and connect it to a cold water pipe. Take the other end of the wire over to your computer and measure the voltage, get an actual number for us.
Or you can pay an electrician to do it. Personally, when I have seen weird ground problems I measure first then decide if I need to call the power company or call an electrician. If its the ground rod at the pole, you call the power company and they have to come for free to fix it. If its in your property then you need an electrician.
So anyway, one time I measured 50VAC from earth to AC line ground. I traced it to the incoming power from the power pole. So I called the power company and demonstrated to their guy what I was measuring. He called his boss and they talked awhile then he started working. They traced the problem to a food freezer in a house down the street that was connected to the same power pole as the place where I was at.
OTOH, in your case you still much about what is going on. Do you have 50VAC on your AC line ground to a cold water pipe. Does is go away when your computer is turned off? If maybe you don't need an electrician, you may need a computer tech to fix your computer.
Does your meter measure frequency too (some do)?
When you use rew and touch the case, what noises are gone? The voltage to the cement floor?
You really need to know if the computer case is ground and what the actual voltage to earth ground is. Get a long wire and connect it to a cold water pipe. Take the other end of the wire over to your computer and measure the voltage, get an actual number for us.
Or you can pay an electrician to do it. Personally, when I have seen weird ground problems I measure first then decide if I need to call the power company or call an electrician. If its the ground rod at the pole, you call the power company and they have to come for free to fix it. If its in your property then you need an electrician.
So anyway, one time I measured 50VAC from earth to AC line ground. I traced it to the incoming power from the power pole. So I called the power company and demonstrated to their guy what I was measuring. He called his boss and they talked awhile then he started working. They traced the problem to a food freezer in a house down the street that was connected to the same power pole as the place where I was at.
OTOH, in your case you still much about what is going on. Do you have 50VAC on your AC line ground to a cold water pipe. Does is go away when your computer is turned off? If maybe you don't need an electrician, you may need a computer tech to fix your computer.
Markw4
A 60 Hz voltage with an amount of 15 volts and 80 volts after touching the floor.
My PC is grounded well and the 3 connectors are connected but the problem with the earthing causes this noise. The cost of re-earthing is very high and I need a method to eliminate this noise. I tried ground loop isolators and electronic isolators that work with a photo coupler but the problem remains.
Is there a significant voltage between the neutral line and the ground? I thought neutral/ground were bonded at either the meter or the main panel. You should have very little voltage between them.
If you are already measuring in your panel, measure from ground in the panel to a water faucet outside. Do you still see 80 volts? If so then turn off all the breakers and see if it goes away. If its still there then call the power company, its their problem.
OTOH if turning off the breakers makes the ground voltage drop to a reasonable value the try turning on the breakers one by one while measuring to see which circuit has the problem.
OTOH if turning off the breakers makes the ground voltage drop to a reasonable value the try turning on the breakers one by one while measuring to see which circuit has the problem.
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10V is too much. If your house wiring is correct and ground is bonded to neutral at the panel, code says the max voltage drop is 5% to the furthest outlet. 5% of 120 is 6, divide by 2 (1/2 for neutral 1/2 for hot) and you get 3V max between neutral and ground, and that would be at 15 or 20A draw on the circuit depending on the breaker limit. So either it is not bonded or you have another fault in your wiring. You could measure some other outlets on other circuits to see if it is just this branch or whole house issue. Is it an old house? One concern I'd have is something in the house using ground as a active conductor. Ground wire under normal circumstances carry zero current. If something like an appliance is using ground as neutral, big problem. I'd definitely want to get to the bottom of this. As MarkW4 says, could be a power company issue. Not sure who "owns" the bond at the meter. I'd try to narrow it as much as possible. Electricians on a hunt for a problem could make for a serious bill. And if a very new house with lots of plastic piping, not sure how reliable a cold water line is anymore. I'm not positive, but I think the pipe into my house is plastic. Granted water is a conductor and eventually it goes to a metal pipe in soil, so some connection is there even with plastic.
I can't tell in my house, I've got a pool and I know it is ground bonded to the soil very well. One giant mesh between soil and pool.
I can't tell in my house, I've got a pool and I know it is ground bonded to the soil very well. One giant mesh between soil and pool.
mikeAtx
The voltage is high but the current is very low and by about 100 mA. As I said it is a kind of inductive voltage that I don't know which electrical device causes this problem. It's better for me to call an electrician man.
Is there a circuit that provides a virtual ground to connect it to my PC case body?
I don't mean a transformer with 3 wires on its secondary side.
Some markets sell a device that provides a virtual earth (EDS system). Is it possible to do it at home?
I mean implementing it in a very small dimension with electronics.
Like Markw4 said, first use the breakers to quickly narrow it down.
Then disconnect everything on that breaker circuit one at a time, until the voltage goes away.
And that item is the problem.
Then disconnect everything on that breaker circuit one at a time, until the voltage goes away.
And that item is the problem.
Curious, how did you measure the 100ma? The ground wire may be smaller than the neutral back to the meter, but not that much smaller. I'd expect near 10A with a 10V difference. But again, this assumes the ground is connected to neutral at the meter. I'd definitely go around the house and check some other outlets on different circuits. Some of this could be very problematic I think. For example, a gas furnace will often use a thermocouple to detect flame. Some of these use ground reference, which may be off in your case. And I'm assuming we are talking about a detached residential house.
How are you measuring the current, and where in the power distribution system you measuring it? With a clamp-on ampmeter? And where, at the computer, at the power panel?
Its like this: You may have more than one problem. The purpose of the ground rod isn't to short 120VAC or 80VAC to ground as a normal condition. There should never be any 80VAC on a ground or on a neutral whether the house ground rod is intact or not. There is another ground rod at the pole anyway. Therefore, you first need to find out what defective part of the power system is putting 80VAC on ground/neutral to begin with. Then you need to make sure the ground rod is good too.
Also, it matters how and where you measure the ground current. You aren't telling us enough details. Its like you think we can see what you are doing and that we should trust that you know what you're doing? Already you have shown that you are in over your head, that you don't have experience troubleshooting something like your electrical system. That may sound harsh, but its well intended. You have some very experienced people trying to help you and you are mostly ignoring what they are telling you.
Its like this: You may have more than one problem. The purpose of the ground rod isn't to short 120VAC or 80VAC to ground as a normal condition. There should never be any 80VAC on a ground or on a neutral whether the house ground rod is intact or not. There is another ground rod at the pole anyway. Therefore, you first need to find out what defective part of the power system is putting 80VAC on ground/neutral to begin with. Then you need to make sure the ground rod is good too.
Also, it matters how and where you measure the ground current. You aren't telling us enough details. Its like you think we can see what you are doing and that we should trust that you know what you're doing? Already you have shown that you are in over your head, that you don't have experience troubleshooting something like your electrical system. That may sound harsh, but its well intended. You have some very experienced people trying to help you and you are mostly ignoring what they are telling you.
Markw4
It seems that the earthing system has a high resistance. I don't have an earth tester to measure the earth resistance and I should call an electrician.With a clamp around the earth wire in the meter box. All devices are turned off except my PC.
I tried all the ways. And the problem remains.
Do you know any circuit that provides a virtual ground? I think If I create a virtual zero-voltage and connect it to my PC body the problem is solved.
I focus more on finding this circuit.
DIY-lover you still don't seem to understand. You have a problem is your system that is creating a life-threatening danger. 100mA at 80VAC can kill you. Whatever is putting that on the line needs to be found and fixed. The ground rod is only a back up device for safety, there is already another one at the power pole. You may have more than one problem, and the one with 80VAC @ 100mA is the first first one that is proper to tackle. The ground rod may fine, they are often imperfect. The ground gets dry, etc. You may be told the ground rod is fine, you just have some bad wiring or equipment in the house. Or you may be told that and that there is a problem with ground rod too. You are not supposed to rely on the ground rod as short circuit for all bad voltages. In reality its not. Fix the more dangerous and immediate problem first, which is 80VAC and 100mA leaking into your ground/neutral system.
Then if you still have an audio problem we will be happy to help you with that.
Then if you still have an audio problem we will be happy to help you with that.
Markw4
I understood and I'm grateful to you. I'll call an electrician nowadays. But I think the noise on my PC sound card may not be solved. Because of it, I want a circuit that provides a zero-voltage.Something like a virtual earth. It seems there is a standard electronic earthing system named EDS as a replacement of an earthing rod. I would like to know how it works. And it is very good to implement it if possible.
EDS seems to be an industrial ground fault detection system using current transformers, not a virtual ground.
It's always better to find the source of the problem, than try to patch it. Plus, this is dangerous.
If you think the PC is the problem, disconnect it completely from everything, and measure the resistance
from the metal case to its AC cord power plug ground pin. There should be continuity.
If so, test your electrical outlet with a tester.
https://www.amazon.com/Receptacle-Tester-Klein-Tools-RT110/dp/B01AKX3AYE/ref=asc_df_B01AKX3AYE/
Beyond this, you should consult a licensed electrician.
If you think the PC is the problem, disconnect it completely from everything, and measure the resistance
from the metal case to its AC cord power plug ground pin. There should be continuity.
If so, test your electrical outlet with a tester.
https://www.amazon.com/Receptacle-Tester-Klein-Tools-RT110/dp/B01AKX3AYE/ref=asc_df_B01AKX3AYE/
Beyond this, you should consult a licensed electrician.
It is imperative that an electrician tests your earthing asap. 100ma is a lethal current if the voltage is high enough.
Once fixed you probably will cure your noisy PC and it will be money well spent compared to trying to use alternatives.
Once fixed you probably will cure your noisy PC and it will be money well spent compared to trying to use alternatives.
I understand what is being measured as follows: a clamp amp meter around the earth wire displays 100 mA and a voltmeter between neutral and earth shows 80 V. This is with only the PC connected and powered.
If so, then these values may indicate more than one problem in your electrical system and/or device.
Could you also measure the voltage between phase (hot) and neutral and phase and earth and report the values?
What is the value of the resistance between neutral and earth prongs of a socket?
If so, then these values may indicate more than one problem in your electrical system and/or device.
Could you also measure the voltage between phase (hot) and neutral and phase and earth and report the values?
What is the value of the resistance between neutral and earth prongs of a socket?
You need a proper earth loop tester to meaure the N-E impedance (they pass a substanial current to simulate a fault).
A few ma from a multimeter will not necessarily give an accurate reading,
A few ma from a multimeter will not necessarily give an accurate reading,