Greetings,
I am in need of some information regarding compression connectors.
We are using a twist-lock style input receptacle on one of our devices. The
terminal connections are of a compression type, i.e., a screw moves two
parallel plates together captivating the lead wire. The terminals are
intended for use with stranded wire. The problem I am encountering is that
of torque relaxation. After the stranded wire is initially torqued into the
terminal, there is a relaxation as the wire now "fans out" between the two
parallel plates. This causes the torque value to drop, sometimes
drastically. (By the way, the stranded wire is neither tinned or
encapsulated in a sleeve/barrel.)
I am looking for more information than that defined in the UL486
series of standards.
1. What defines an "acceptable connection"? What is the criteria of an
"acceptable connection" other than the usual standard statement of
"mechanically secured" and "appropriate for the connection"?
2. Are there any tests that can be perfornmed to determine if the
connection is reliable? (Other than the impedance test identified in C22.2
No. 0.4 for grounding). Remember, these are also the current carrying
conductors.
3. What checks could I use to insure that the terminal torque would
remain in the acceptable range?
4. Are there any standards, guidelines, books, notes and/or codes that
would help me define what an acceptable connection is?
5. Has anyone else encountered this or a similar problem?
Your comments would be appreciated.
John F. Dudek, Manager
Product Safety Engineering
Corcom Inc.
