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Explaining to me about electricity is like explaining to your Grand-Ma about it. So please be kind and gentle :)

I bought an Earthing Mat from "http://www.amazon.com/dp/B003RLOBOK". It includes a conductive mat to which I connect a white-wire whose other end goes into an earthing point on my wall. As long as a person's body is in contact with the mat, he is getting earthed.

But how do I verify/measure if the conductive mat is getting earthed correctly? (in effect I am getting earthed correctly).

I called up an electrician over to my house who demonstrated and verified that the white-wire (connected to mat) is getting earthed. After inserting one end of the white wire into the earthed socket, he touched one wire of a bulb (with 2 loose wires) to the other end of white-wire. The bulb lit up and he said that white wire is getting earthed.

enter image description here

But he didn't know how to verify the conductive mat. All he said that this looks like rubber and should not work.

I come with an almost zero electrical knowledge. So how can a novice like me verify if the conductive mat is working as it should.

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    \$\begingroup\$ Conductive mats aren't very conductive; their purpose is to dissipate static electricity. Normally you only need one if you're assembling static sensitive CMOS devices in a low humidity area - is that what this is for? \$\endgroup\$ – pjc50 Jun 6 '13 at 14:23
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    \$\begingroup\$ nope...this is related to wellnessmama.com/5600/how-to-get-healthy-while-you-sleep since its difficult to measure the exact effect of this, I wanted to atleast be sure that my body is in touch with a material thats getting grounded \$\endgroup\$ – Jags Jun 6 '13 at 16:39
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    \$\begingroup\$ sigh "defusing excess positive electrons" and a long list of cure-all stuff. Electrons aren't positive. I'm just surprised it doesn't mention curing cancer, like most of these do. The heat map, in conveniently leaving out the conditions under which the images were taken, is complete BS. My mother basically goes from one product like this to the next, totally believing each and every one of them works. Well, guess what... it's a scam. They're preying on ignorance. This kind of stuff is so far removed from appropriate on this site it isn't even funny. \$\endgroup\$ – darron Jun 7 '13 at 0:50
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    \$\begingroup\$ To actually offer way more explanation than this product deserves... you're constantly getting grounded (or "earthed") at many points during the day. Touch the metal housing of just about any product plugged into the wall, and you're grounded. It doesn't take 30 minutes to get balanced out. It's fractions of a second. As for the heat map: lying down just about ANYWHERE for 30 minutes is going to reduce inflammation. Not, that is, that I even accept that those marginally hotter spots indicate inflammation at all. The big color range shift between the two should be a clue that something's off. \$\endgroup\$ – darron Jun 7 '13 at 1:27
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    \$\begingroup\$ Look, I don't mean to come off as attacking you personally. A lot of people fall for this stuff. The immediate person selling it could actually believe it works. That doesn't change the fact that at some point in the past, some unscrupulous fraud thought it up as a plausible-enough-to-sell item. (whoever did the heat maps pretty much knows it's snake oil) It sounds plausible to people who don't know much about physics or EE because it's SUPPOSED to. It's witch doctor & snake oil stuff, and we SHOULD be past this but unfortunately we aren't. \$\endgroup\$ – darron Jun 7 '13 at 2:00
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Earthing mats do look like silicone rubber, but are made of, or coated with, some flexible conductive material. Therefore appearance alone is insufficient to assume it is not earthed.

If you have one of the screwdriver type mains testers, it is easy to verify earthing:

enter image description here (source)

Grab the metal clip at the back of the tester firmly using the mat as a glove - without directly touching the clip with any part of the body - and insert the screwdriver head into the live point of any mains socket that is switched on. If the mat is earthed, the tester will light up, as the tester works by earthing itself through the clip, then through the human body or other earthing connection.

Of course, also check if the tester lights up at the socket in the first place, by touching the clip with your hand.

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  • \$\begingroup\$ hmmm..thats sounds easy to test! I will get a tester and see what it does..thanks for your reply \$\endgroup\$ – Jags Jun 6 '13 at 13:46
  • \$\begingroup\$ I do not know, maybe this is limited to 230V mains, but my tester lights up even without touching the metal clip - I guess capacitive coupling is enough for the neon bulb to glow. A more modern electronic one also does not require touching any metal part. \$\endgroup\$ – Pentium100 Jun 6 '13 at 13:49
  • \$\begingroup\$ @Pentium100 I just checked with my cheap old-fashioned neon tester, it lights up only if my fingers are within about 0.5 mm of the tester (capacitive, no doubt). When I hold it with plastic tongs, fingers about 5 mm away, it does not light up. Perhaps the modern ones are much more sensitive? \$\endgroup\$ – Anindo Ghosh Jun 6 '13 at 13:53
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If you have a multimeter, test the resistance of the mat by touching it with both probes a few centimetres apart. It could be hundreds of thousands of ohms, but not infinite - there should be some large resistance between the mat and earth so that when the static voltage discharges, only a little current flows (IIRC there's no point in having it otherwise - it's the current that actually kills the components, not the charge), and so it doesn't cause other issues accidentally earthing equipment or circuits.

You could also measure resistance between the surface of the mat and an earth point; this will include another several mega-ohms for the resistor which should be in the earthing block you attach it to (again to reduce current when discharging).

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    \$\begingroup\$ didn't understand most if it..but I will try to get my hands on a multimeter..touch its probes on mat and look for "hundreds of thousands of ohms"..thanks for your reply \$\endgroup\$ – Jags Jun 6 '13 at 13:49
  • \$\begingroup\$ If you're going to be doing any kind of electrical engineering (with actual components, not just on paper) then you need to get a good multimeter. YouTube EEVBlog and multimeters. Dave Jones has some excellent recommendations for them at all budget levels (well, $50 and up). \$\endgroup\$ – cbmeeks Jul 7 '15 at 19:46
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If your electrician was able to light an incandescent bulb, (not a neon), even a small one, between any accessible part of that pad and the live terminal on the wall, as shown, you have a relatively dangerous product. There should be a current-limiting resistor (the fraudsters say 100,000 ohms on the product sites), but this should be located at the wall plug, not somewhere in the pad. If the product relies simply on the supposedly low conductivity of the pad surface, which is bound to be variable and susceptible to aging or wetting, and you touched some other device that had an electrical fault, like a lamp, you'd be asking for a bad jolt or much worse. One of my friends just fell for this snake oil, and I'm going to check out the device soon. Almost any garden-variety multimeter will tell the tale.
While you're at it, do what most of do very casually: measure your skin resistance with the meter, by, say, holding one probe in each hand, and you will get an idea of what that's like. Also, you may wish to read about the entire concept on many debunking websites.

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  • \$\begingroup\$ "There should be a current-limiting resistor (the fraudsters say 100,000 ohms on the product sites), but this should be located at the wall plug, not somewhere in the pad." There is a current-limiting resistor located at the wall plug as far as I could tell with my product. Earthing.com is where I got it from. \$\endgroup\$ – user80552 Jul 7 '15 at 18:56

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