Earthing mat is making me ill !

[sunnyod]

It doesn't make sense to use shielded cable for an earth connection, because the main method by which shielding works (e.g. to stop car ignition systems causing crackling noises on your stereo) is to surround the important conductor with an earthed one. So you would be shielding an earthed wire with another earthed wire. There are lab techniques where this is necessary but it is not applicable to your earth mat.

It would be like trying to wash tap water off a surface using tap water.

Ah, thanks for the explanation... makes sense

 

[Lucien Nunes]

I have a multimeter. If I put the black pin on earth (like metal surface on radiator pipe?) and red pin on the mat connected to the mains, what would I see if the earthing is faulty?

You can't effectively test earthing like that. If the pipe is connected to earth it is likely to be via the earthing system of your installation, so you should not see any significant voltage between the two, or between any two supposedly earthed things. Say less than a couple of volts on the 20V AC range. But it doesn't tell you that the earthing is sound, for that you need the proper test equipment that an electrician would use.

You could however check and post the Ra of the electrode and/or Zs of the supply from the EICR, which would be informative.

 

[sunnyod]

FYI I just nicked a skewer from the missus and stamped it into the ground outside and connected the mat cable to it. Looks like its earthing correctly. Is there a way to test it? Mat feels different, no more tingling

 

[Lucien Nunes]

Put meter leads into COM and V/Ω. Set the meter to 200V AC (if it has separate switched ranges). Disconnect both wires from the mat. Connect one probe of the meter to the wire from outside and the other to the wire from your socket that had been used to earth the mat. For your safety, if you are inside, treat the wire from outside as though it were live, and vice versa.

Report the reading. If it is less than 20V, switch down to 20V range. Better still, post a pic of the meter displaying the reading, for an independent observation that it is correctly set.

 

[sunnyod]

Not sure if I’ve done it right, manual was showing no reading. I switched to auto and it would flash up a value (normally around 42-44) then reset. This is the read I managed to capture

 

[brianmoooore]

You are on the resistance range. AC volts is two to the left.

 

[sunnyod]

Oops. Thanks Brian...

 

[MJPD29]

Although it is almost certainly all in your head, if your that obsessed with earthing yourself buy a metal bed frame stick a spike in the ground and earth the bed. Problem solved.

 

[sunnyod]

Although it is almost certainly all in your head, if your that obsessed with earthing yourself buy a metal bed frame stick a spike in the ground and earth the bed. Problem solved.

You'll probably still think I'm crazy after watching this, but it could be really eye opening for you too

https://s3-us-west-2.amazonaws.com/liveconnected/down-to-earth-cropped-compressed.mp4

 

[Lucien Nunes]

0.08 volts, 80 millivolts. That's the sort of reading I was expecting. There are some caveats about its accuracy but the main one (measurement lead resistance) has been dealt with already when you showed the resistance reading. The other important one is that the meter will be reading only the voltage present at frequencies within its measurement capability, which includes all electrical power lines. However if you were under the mast of a radio or TV station transmitter, that might not be a sufficient indication that there were not strong fields at radio frequencies inducing a voltage that the multimeter cannot sense.

I think you need to look carefully at what other factors could be influencing your sensation of the effects of the mat; they can be real effects, and again I must say I am not doubting what you experience. But 80mV w.r.t. true earth, contacting the body in at one point only and relying on the stray capacitance to earth to complete the circuit, cannot realistically pass enough current to create a sensory effect.

The stray capacitance of a body is typically less than 1nF, more likely around 200pF. It will be less to true earth if part of your environment is shielded from earth by the mat at mains earth. Let's call it 500pF anyway.
At 50Hz, 500pF will have a capacitive reactance of 1/(2*PI*50*5e-10) ~6MΩ
0.08V between mat and true earth gives a touch current between you and the mat of 0.08/6M = 13 nanoamps. I can just about feel a current of 10,000 times that, when concentrated in my finger and I brush it over a surface to maximise the sensory response to muscular reaction (like a dowsing rod). It takes about 100,000 times that current to feel as an actual electrical tingle.

You'll probably still think I'm crazy after watching this, but it could be really eye opening for you too

I will watch the whole thing. I have just watched the first two minutes and counted six factual errors or abstract ideas presented as facts.