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A few weeks back, I was standing at a Hornsey rail station (in the UK) which uses overhead lines, and particularly has a number of parallel rail lines, all close to the platform.

While I was standing there, I went to hold hands with my girlfriend, and experienced a peculiar sensation in my fingertips, almost as if there were very large ridges on her hands. I've felt this before, touching a metal bodied laptop computer that was seemingly not earthed - dragging my finger across the surface my finger felt as if it was jumping along the surface, despite it being a smooth aluminium surface.

Is this a result of the overhead lines inducing a reciprocating current through my arm and/or fingertips? Is there some other feature of the railway that could cause this effect? And were we in any danger of any sort?

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    $\begingroup$ Very closely related, if not essentially a duplicate: physics.stackexchange.com/q/29016 $\endgroup$ – user10851 Jan 28 '14 at 21:51
  • $\begingroup$ yes, I have looked at that - I'm not clear on whether it is the human body or the bicycle picking up current there. $\endgroup$ – penguat Jan 28 '14 at 23:45
  • $\begingroup$ In the laptop case, was the laptop plugged in for charging ? What supply ? In case of your girlfriend, what type of shoes& socks were you two wearing (it highly affects grounding), did you somehow eliminate the possibility of static ? Also were you feeling ridges and bouncing as a sort of repulsion ? $\endgroup$ – Rijul Gupta Feb 4 '14 at 19:00
  • $\begingroup$ It was a macbook, plugged in and charging on an apple power adaptor. We were both wearing leather topped, rubber-soled shoes and cotton socks, although it was a wet day. I don't think either of us was earthed but can't rule it out. I'm discounting static as an explanation because usually static is a short sharp shock, and wouldn't buzz like that. $\endgroup$ – penguat Feb 5 '14 at 10:19
  • $\begingroup$ the buzzing sensation was very much like dragging my finger along a surface with ridges spaced about a millimetre apart, perhaps half a millimetre in depth? There was certainly a repulsive component (electromagnetically repulsive!) although it's hard to tell beyond that as of course I was also pressing my hand against my girlfriend's $\endgroup$ – penguat Feb 5 '14 at 10:23
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The electric field of an infinite conducting wire varies as 1/r not 1/r^2 as for a point source. A high voltage line AC line at low elevation acting upon two people at least one of whom is well-grounded could be physiologically detectable though polarization and inductance. If it is DC, much less so for obvious reasons.

How much requires simple measurement rather than complex calculation. Bring along a good VOM digital multi-tester.

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  • $\begingroup$ interestingly, I don't know that either of us was well grounded, what effect would that have? $\endgroup$ – penguat Feb 4 '14 at 18:26

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