Just adding to what Rich has said below about methods. The double
crimp (or insulation crimp) is probably the best method because both crimps
are made with the same tool at the same time so there is no manufacturing
cost penalty, and several vendors supply the parts and I don't believe that
there is any appreciable cost penalty for the parts. Simpler solutions are
available if needed. You can tie one wire to the next with a wire tie for
example. The first attachment point is the wire to connector pin, the second
retention method then is the wire tie which is anchoring the wire itself to
an adjacent pin, standoff or whatever.
I prefer the first method for several reasons but wanted to point
out the next most common, in my experience, method.
Gary
-----Original Message-----
From: Rich Nute [mailto:ri...@sdd.hp.com]
Sent: Tuesday, September 19, 2000 4:08 PM
To: andy.v...@mts.com
Cc: emc-p...@majordomo.ieee.org
Subject: Re: Double Retention
Hi Andy:
> I have been told that either "double crimp" terminals (fast-ons, ring,
> spade) must be used for insulated wire, or a secondary method must be
used
> to secure the wire's insulation near the point of connection. I have
not
> seen this described in the standards I have read or in the archived
emails
> on the RCIC database - where should I look? At this point, I don't even
> know if this is a UL or a LVD thing.
This is a long-standing, traditional, and semi-secret
safety requirement. In my experience, it has been
applied by both CSA and UL.
The requirement is based on the concept that safety
must be provided both for normal conditions and in
the event of a fault.
Where a wire could come loose and bridge a safety
insulation, then that wire must have a second
mechanical scheme that prevents the wire from
bridging the insulation.
The requirement is stated in IEC 60950 and its
clones in Sub-clause 3.3.4 for power supply cord
wires. This same requirement MAY be applied to
other wires at hazardous voltage by the many
different certification engineers, each of whom
has a different reason for doing so.
There is a similar requirement for containment of
strands of stranded wire. See Sub-clause 3.3.9.
You didn't ask what are the secondary methods.
Any secondary method that keeps the wire from
bridging a safety insulation is generally
acceptable.
The "double crimp" is acceptable because the
first crimp is to the wire, and the second crimp
is to the insulation. Two, more-or-less
independent fixings.
Best regards,
Rich
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson: pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson: pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
