5 Sep
2014
5 Sep
'14
4:16 p.m.
On 09/05/2014 03:30 PM, drlegendre . wrote:
I only discovered this issue last week, in the process
of working on the
Altair, when I felt that tell-tale buzz on my fingertips as they happened
to lightly graze the chassis at one point. Same feel you get from a vintage
amp with a 2-wire cord and an AC line bypass to chassis.. the so-called
"Death Cap", in the lingo of some guitar doofuses who don't seem to grasp
the concept of impedances, and how little current that 50-100nF cap can
actually pass through the resistance of a human body at 60hz.
A bit of advice--when you do get it right, please also install a ground
fault interrupter also. We want you around for a few more years.
FWIW, I've got an industrial PC supply that will get me a little
"tingle" if not properly grounded, so perhaps what you're seeing isn't
that uncommon.
At any rate, I don't think you need to worry about 90 microamps leakage.
Most US GFCIs don't trip until the leakage current is somewhere around
6 ma--or about 60 times what you're seeing.
--Chuck