My earthing/Ground pin shows voltage

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Thread Starter

Prof R K Gupta

When I measure with multimeter, I see Phase to neutral 220 V; Neutral to Earth 35 V and Phase to earth only 150 V.

When I switch on table top computer or desktop, the voltage in earth to neutral rises to 65-68V.

I have 220V AC single phase supply in my home. This earth voltage is seen in all sockets.

I think earth pin should never show any voltage and neutral to earth should not show any voltage or maybe a few Volts. And phase to earth should show full 220V.

The tester shows dim light when gadgets like fridge etc are touched on their body nuts.
 
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Bob Peterson

Presumably what you are referring to as "neutral" is supposed to be connected to earth at your service point. If so, there is no way the values you are measuring could possibly be true in a single phase system.

It could be a measurement error (or an operator error in taking the measurements).

It might be that there is no actual connection at your service to earth which would make the voltage from what you are calling neutral to earth float.

It is very hard to give you any guidance on this situation without looking at it closely and that is not possible over the Internet. I am not sure there is any cause for concern but if you are bothered by it, you might want to call in a competent electrician to have a look.

--
Bob
http://ilbob.blogspot.com/
 
W

If you are reading this at the receptacle without a load plugged in, it is possible that the neutral to ground connection is open and your AC is floating which could account for the strange voltage readings. Check this connection at the transformer or the first downstream first panel.

William (Bill) L. Mostia, Jr. PE
Fellow
SIS-TECH Solutions, LP

Any information is provided on Caveat Emptor basis.
 
J
I saw this behavior in damaged wires and some insulation faults in equipments and electric installations. Moisture or water inside the cables runs can also be causing this.
 
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William Hinton

I have heard of this many times, saw it a few times and the causes and solutions were the same.

Some older homes had their ground wire connected to the water pipe. This seemed to work pretty well until the well pump was replaced and the pipe was replaced with PVC pipe.

The second most likely cause is knocking the ground wire off your ground rod with the lawn mower. The ground wire connects to the ground rod with an acorn clamp. This connection needs to be clean, tight and it can not have corrosion. This is difficult when some of them are under ground.

One time it was discovered that the split-bolt connector was loose at the weather-head for the neutral.

That’s about it, I hope this helps,

William Hinton
Retired and liking it
 
check the neutral & earth wires are connected concern places with out any contact resistance (i.e. loose or rust at terminals).

or may be you need to improve the conductivity of your earth pit, either pouring water or re-install a new earth pit.
 
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Prof .P.Aravindan

It is obviously shown that your earth electrode is open circuited. It is very danger for your equipment and operating persons. Immediately you have to check your neutral earthing electrode with a qualified electrician. The NEV (Neutral to Earth Voltage) should not exceed to 1-5 Volt Max. It would be possible if you properly maintain the earthing of your system.

Prof.P.Aravindan
Electrical Consultant.
[email protected]
 
The "Neutral" should be connected to the ground at the breaker panel to have a properly grounded system. This will have an adverse effect on your overcurrent devices working properly.
 
D

Dr R K Gupta

Thanks for reply. But neutral and earth are not connected together. These should never be. IN single phase supply the utility company provided two wires.One phase and one neutral that goes to supply grid or transformer. Earthing is internal thing where every consumer instals his own earthing pit and ground earthing wire. Hence neutral to earth should never show voltage. In my home neutral and earth are NOT connencted as you mentioned. SO why it is showing voltage. I mean Neutral to earth point of power socket? And this goes high when machine like PC is switched on.
 
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Bruce Durdle

Whether or not the protective earth (PE) and power supply neutral (N) are connected depends on the local supply requirements, and varies considerably depending on where you are in the world.

In my residence, there is a local PE earth connection, and an incoming power supply neutral connection. The transformer neutral is also connected to earth at the transformer. These are connected solidly in the main switchboard. In IEC terminology (see http://en.wikipedia.org/wiki/Earthing_system) this is TN-C-S. It is also locally referred to as MEN for multiple-earthed neutral.

If there is no local connection between earth and neutral, there may be a small voltage due to voltage drop along the neutral. Find out what type of earthing your local supply system is supposed to use. If there are anomalies, then get the installation checked by someone who knows what he or she is doing - this could be a major safety hazard.
 
This sounds very dangerous, you must get a competent electrician to check it out, Voltage on the exposed metal of your refrigerator could cause electrocution.

In most parts of the world the neutral and ground are connected together at the panel however where you live (you didn't say) it may be different.
 
Even I had faced this issue a couple of days back, when in investigated I found that there was a wrong connection (phase connected to earth) in a new spike guard that I had bought recently. Since in one place there was a wrong connection I was receiving phase in earth connection in the entire house. Please check for any wrong connection in the three pin or in any other gadget.
 
the only way to get the earth line, Inspect the building wiring, check the earth connection coming from, back trace it. It must be terminated to a proper earth pit. You will find and loose/broken connection in earth line or your earth pit is not effective.

If earth pit is not effective, treat some water & salt to the nearby soil area.

If still this point exists, prepare a new earth pit and connect it to your home earth line.

For a good and healthy system,
P-N=220-230v, P-E=220-225V, N-E=3-5V (neutral should be at negative potential). this is standard for India.
 
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