Doug,
If I understand you correctly, you are referring to the remaining connector (or
pins or traces) in the equipment which is still under power.
O.K., let me tell you what UL and CSA made me do with equipment that is NOT
user accessible, but only accessible to trained service personnel. There was
no hazardous voltage (equipment was -48 Vdc nominal); however, there was
definitely Hazardous Energy if the serviceman pushed his hand inside up to his
elbow, and if his nails were decorated with metal studs or if he somehow
managed to bridge with a tool in a very narrow tube-like area. We never
thought that this type of deliberate sabotage was "likely to occur". However,
the CSA evaluating engineer made us place a label, such as when the supply was
pulled out, the label immediately were made visible, that stated the usual....
WARNING! Hazardous Energy! .......
If this is user accessible equipment, you can't even rely on such a label! The
user might decide to try what Hazardous Energy feels like!
O.K., here comes another story! In my late twenties, when braces were not so
frequently worn by even kids, I found myself with a full set of braces. The
orthodontist warned me not to bite into apples (eat slices instead), not to
crack nuts with my teeth, etc, etc, and not to chew gum. Gum? I never chew
gum, but I was intrigued. What possible harm could some soft gum do to you?
So I bought some gum and proceeded to chew. In the beginning there was
absolutely no problem. Then later, when the gum lost its sugar and other
additives (and remained pure rubber or latex or whatever it transmorphed into)
the whole goop stuck to the braces and in between and underneath the wires.
It took me at least 40 minutes with a toothpick to dislodge tiny bits of gum
that were stuck all over the braces. It was more than a day that I really
felt I got all of it out.
Never underestimate the stupidity of people challenged by some intriguing label
or instruction! However, a trained serviceman should accept your label at face
value.
Tania Grant
[email protected]
----- Original Message -----
From: Doug McKean
Sent: Wednesday, June 20, 2001 6:31 PM
To: EMC-PSTC Discussion Group
Subject: Re: Hot Swappable Power Supplies ?
What's the accessibility to pins or traces or
anything carrying hazardous energy when
a power supply is pulled out?
- Doug
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/
To cancel your subscription, send mail to:
[email protected]
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Michael Garretson: [email protected]
Dave Heald [email protected]
For policy questions, send mail to:
Richard Nute: [email protected]
Jim Bacher: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.rcic.com/ click on "Virtual Conference Hall,"
