I have noticed that it seems to be common practice in my area to strip stranded wire and leave the insulation on the end of the wire to hold the strands together and then wrap this around a termination screw on a recepticle or a switch. I am sure that I saw a comment and illustration in an old Handbook I had that illustrated this as being a wrong practice, but have looked since and cannot seem to locate this information. In my understanding, stranded should only be terminated using crimp ons or on a termination screw with a cup or where the device has pressure plates. Could anyone help on this?
While the terminals themselves are listed for solid or stranded wire, what are your thoughts on the specific technique described by gunther? Would you consider this good or bad workmanship?
Specifically: taking the stranded wire, stripping it so that a sufficient length of conductor is exposed, but _leaving_ a length of insulation on the end of the wire, and then wrapping this around the screw terminal. This would keep the strands from coming apart, but would leave and extra dangling bit of wire if the insulation were to fall off.
The technique that I like to use is to strip stranded wire, leaving a bit of insulation on, then using this insulated section to grab and twist the stranded wire tightly, and then to cut this insulated section off. I twist the wire in the 'reverse' direction so that it doesn't 'birds-nest' when I tighten it under the screw. I've sometimes thought about leaving a length of insulation on the wire after the screw terminal, however.
#86186 - 09/25/0304:18 PMRe: Stranded use in recepticle terminations
I still believe that the best way to terminate stranded wire on receptacles and switches is to twist the strands counterclockwise prior to terminating. This ensures that tightening the screw will further twist the wires during tightening, as opposed to the untwisting that would occur if the wires were left twisted clockwise.
Try it sometime!
#86188 - 09/25/0308:13 PMRe: Stranded use in recepticle terminations
I have tried the counterclockwise twist after I saw your suggestion here.
Makes attaching new plugs and sockets when rewiring table & floor lamps much easier!!!!
Looks neater too. ********************************************* Gunther, by your argument, then lampholders for table lamps and most regular household Nema 1-15 plugs and connectors must only be wired with solid wire.
The screws on these things sure don't have any pressure plates or "cups". And sometimes I think screws are too small to do the job properly....and in a lot of cases there is no space for crimp-on terminals. You have no choice but to wrap the wire directly around the terminal screw.
[This message has been edited by SvenNYC (edited 09-26-2003).]
#86190 - 09/27/0306:22 AMRe: Stranded use in recepticle terminations
Thanks everyone for your thought-provoking replies and insights. I especially like the suggestion of cutting off the tailing end of insulation after tightening the terminal screw. Its great to have a place to share experience so that perhaps the quality and craftsmanship of the trade can be improved. Just for clarification, I am not trying to advance argument, just trying to learn. Thanks.