Joseph Gwinn wrote:
I saw this article in The New England Journal of Medicine. Here is the
URL, unfortunately behind a paywall.

http://content.nejm.org/cgi/content/short/360/13/1363

The gist is that a danish doctor had a patient who was getting
inappropriate cardiac shocks from an ICD (implantable cardioverter-
defibrillator) while in the shower, which turned out to be due to bad
house wiring causing a 50 Hz leakage current from showerhead to floor
drain.

A current of 3.5 to 4.0 milliamps is not usually felt, but can spoof the
ICD, which looks for such signals lasting about 300 milliseconds.

This would be easy to check with a voltmeter. And to prevent by
running a ground wire from showerhead to drain pipe.

Joe Gwinn

IIRC in the UK all runs of conductive pipe, typically copper in my
experience, have to be earthed to prevent this sort of thing. Having
said that I do know a guy that did some DIY and had a section of plastic
pipe joining 2 copper piping systems in his house which left one section
unearthed and this situation arose where the unearthed section became
live, luckily no one was injured just s few minor shocks.