Inappropriate ICD Shocks Caused by External Electrical Noise

I saw this article in The New England Journal of Medicine. Here is the
URL, unfortunately behind a paywall.
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
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
Reply to
Joseph Gwinn
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"Joseph Gwinn" wrote: clip) This would be easy to check with a voltmeter. And to prevent by
^^^^^^^^^^^^^^^^^^^^^ I wouldn't hesitate to run a ground wire as a temporary fix, but how do we know it will carry only 4 or 5 mils? It will carry current 24/7--I would try to figure out how line voltage is getting to the shower head, and fix that.
Reply to
Leo Lichtman
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.
Reply to
David Billington
I suspect it was a point-of-use waterheater in the head. Unknown in the US; they are seen elsewhere.
Reply to
David Lesher
I have seen them in Costa Rica. So they are in the West.
Reply to
Calif Bill
Reading some of the replies - I have this to add.
Hot water lines are very often isolated from the tank to prevent current leakage by dissimilar metals which can eat a tank up.
This isolation can be the issue - if the pipe doesn't dive under a concrete slab or underground.
Remember many places have only air and brackets. Think non-1 family house.
Wire running a length along a pipe - in a race way - it being a single wire e.g. one line of a 220 going to a heater... The other wire is there but not as neat..
The wire induces current in the water pipe and the nominal voltage drop drives a nominal current in the water stream.
Joseph Gw> I saw this article in The New England Journal of Medicine. Here is the
Reply to
Martin H. Eastburn
Belt and suspenders.
Joe Gwinn
Reply to
Joseph Gwinn
I've seen it and fixed it. No ICD triggers, but the sensitive people felt it in the shower and complained. Took me a while to track it down.
Combinations of idiocy. They had an open Neutral wire and a faked-in Neutral wire headed out to the wellhead. 2 HP submersible.
Now this wouldn't be a problem normally, since the well is 240V and only time there would be a load on the Neutral is when they were working on the well and wanted to use 120V power tools or a light.
But then they tapped off the well for 120V lights and appliances on a semi-permanent residence tent - they saw a white wire and figured they were solid.... And all the unbalanced Neutral current was going through the water to find a ground, and made it up the water line all the way to the shower heads in the permanent building.
Had to re-pull the power lines (including fresh Neutral and Ground) all the way out to the well, and of course the problem vanished.
Reply to
Bruce L. Bergman
I couldn't get much from the website. Who made the ICD in question, please?
Reply to
Don Foreman
They have them here in the US. They're just not well known. Karl
Reply to
They didn't mention any makes or models. They implied that the problem is general.
Joe Gwinn
Reply to
Joseph Gwinn

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