electrics - "strange" shock risk?

[dave]

The other night I noticed a table lamp fitted with a "low-energy" lamp (one with three loops of glass) was playing up. It seemed as if the actual lamp fitting was the problem so, reaching inside the shade and carfully holding the insulated base of the map itself I attempted to press it upwards, to see if this fixed the problem (low light output and flickering). Anyway, no solution there. However, when I was moving my hand from the shade I felt what seemed to be a decent electric shock! I've had a few (E.S's) in my time so know what they feel like.

This however felt like shock + intense heat at a very small area. Purely a long shot but I wonder if the LL lamps have an as-yet unknown failure mode where by a "micro-pinhole" in the glass can provide a path to earth. I know friends, that this is downright wacky

- but that is what is felt like. It was a *very* localised pinhole type stab - and rather painful. No spikey glass bits seen on lamp.

Also, when I replaced the lamp (which I should have kept for investigation), with a brand new one, it worked just fine with NO changes to the wiring. Plus btw, no shocks when touching any part of it.

[meow2222]

If the glass pinholed then the bulb would never strike. These sort of experiences can be generated in the joints and nerves, they arent always a genuine shock.

NT

[Andrew Mawson]

moving

like.

wacky

You >>CHANGED

[chrisj.doran]

I'm sure I've heard of something like this before, maybe in connection with radio valves. A possibility is that an impurity or air bubble in the glass might render it conductive at one point, though still vacuum- tight. It's a pity you didn't keep the bulb.

But I agree that "joints and nerves" are a common source of "electric shocks". Perhaps someone with medical knowledge will explain it properly.

Chris

[Dave W]

The voltage across the tube is very high, and at high frequency. Maybe it sparked over to your finger via a gap between the glass and the holder?

Dave W

[meow2222]

yes, 35v is deadly. (not sure what the smiley for sarcasm is)

NT

[Clint Sharp]

In message , [e-mail] writes

I think you'll find that referenced to earth it's a mite higher than

35v.