Lazy Electrical Question

Nov 08, 2015 52 Replies

Hi all,



Does anyone know a ballpark figure for a person's resistance to earth if he's standing in stockinged feet in his living room? I have a high impedance ohmeter somewhere and will measure it myself if I absolutely have to, but I've just got comfy on the sofa and am hoping someone else will do it for me, or already knows the answer, cheers.


Depends if the person has webbed feet or not.

Is the floor running with water, made of steel, non-resin-coated carbon fibre or somesuch? Rubber, wood, lino, carpet, tile, stone? Suspended or solid underneath?

Nick

In message , Cursitor Doom writes

It maybe quite low, can I suggest you try measuring it with an old wind up Megger? Maybe not.........

Conventional hesian-backed carpet (pinkish colour) over floorboards supported by joists.

Actually that's not a bad idea! I've got an old 250V Megger somewhere....

The main factor will be how long it was since he changed his stockings.

As regards mains, it's not the resistance you'd be interested in, but the impedance.

It would also depend on what the socks are made of and how thick.

I don't know if that's a wind up, but he's going to be megger surprised if he does use it.

The OP should remember to post a pic of the experiment online.

NT

when I was working at an electrical manufacturer in the late 1950s, someone persuaded one of the young ladies in the lab, that if she held the two leads while he wound the handle, the machine would read her weight.

The ohmmeter will be very innaccurate. By far the best way is to measure (or assume) the mains voltage then complete the circuit manually and measure the current through the body. For best results, a representative range of body parts should be used as the live connection point.

Let us know how you get on.

Cheers

Are you implying there is a capacitive or inductive nature to the human body?

I suppose it is possible to wrap yourself the odd turn or two around some soft iron? :-)

Now *that* is the Gold Standard method! If I get time tomorrow I'll give it a whirl.

Yeah, we pulled tricks like this all the time back in the good old days. And guess what? NOBODY got injured, much less killed. We're living in pussyfied times today. :(

That reminds me of a similar occasion when we convinced another young woman that placing the electrodes from a 500V Megger on her stomach would burn off excess fat. "Keep cranking, keep cranking!" she exclaimed, through gritted teeth. Seriously!

Your skin has quitehigh resistance. However you bodily fluids have low resistence. Electric currents in the body follow the arteries and veins.

There is no answer,it largely depends on the area of contact and the contact pressure. If you get your ohmmeter out, you'll find your resistance depend on how wet your fingers are and how hard you squeeze the probes.

Heh heh. Not at all. If you squeeze the probes really hard, it doesn't hurt a bit. If you don't, it don't half make you jump.

Normal apprentice's trick to show how "hard" they are.

ISTM use of a Megger will mainly show that thicker people have less resistance :)

Drivel. I can see you have no idea what impedance is.

Are they wearing M&S FreshFeet socks with embedded silver particles?

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