Science Questions

If you urinate on an electric fence will it shock you?

Dave -   I can’t say any reason why not and I grew up in a rural area,  and it was one thing I was told very, very definitely not to do, with such force.  I have a feeling various groups that were telling me had personal experience in this area.  An electric fence, basically, works by having a wire which is put up to a couple of thousand volts with a very, very limited current.  So the current will flow through you but the amount of current that can flow is not going to be dangerous.

Now an electric current will flow quite well through your body because your body’s got water in it with some salt in there.  So the salt has got ions in it which means the electricity can flow through it quite nicely.  Urine is water with some salts in it so electricity is going to flow through it very nicely.  So yes, as far as I know, yes, you can certainly get shock in that manner, yes.

Chris -   Is that true where the guy pees on the underground and gets a bit of a shock.

Dave -   I don’t…

Chris -   Would it be fatal?  Would there be enough current flowing in the urine stream, do you think, to get...?

Dave -   I don’t know.  The underground is a much – it’s about 600 volts, I think, which...

Chris -   DC?

Dave -   DC.  So I would have thought that this will be plenty there.  Again, it depends how well where the current can flow, if he’s attached to earth quite nicely. If he’s wearing rubber Wellington boots, probably less likely.

Chris -   And will the electricity flow up the urine at the speed of light – i.e. the speed electricity?

Dave -   It should flow up the urine at about the speed of electricity, yes.

Chris -   So it would be an instantaneous shock?  I think there’s a Kitchen Science in this.

Chris -   And I think we should just send Dave out to try it.

Helen -   Well I think we should just take Dave’s word for it but it does happen so don’t go and pee in the underground.  Thank you very much.

August 2009