Re: gEDA-user: Contact reliability

[Bert Douglas <bertd@xxxxxxxxxxxxx>]

Karel Kulhavy wrote:

> On Wed, Jan 19, 2005 at 03:25:22PM -0600, Bert Douglas wrote:
>
> > > > Ugh.  I despise wire nuts.
> > >
> > >
> > > What does the wire nut do? Is it a plastic cap that protects the twisted
> > > place against untwisting?
> > >
> > > Cl<
> > It is used for wiring of power inside buildings.
> > It is a copper-plated helical steel spring, inside of a piece of plastic 
> > with one open end.
>
>
> How does it work? I don't get it.
>
> Cl<

Well, it is used exclusively on solid (not stranded) wire, generally of 
size 10AWG to 16AWG.

You remove about 1/2 inch (more or less) of insulation from the ends of 
two or three wires.  You insert the bare ends of the wires into the 
"nut", and you twist the nut.  You keep twisting until the torque 
increases sufficiently.  That's it.

You have to be careful that the bare ends of the wires are fully 
overlapped, and that one end is not pushed in more than the others.

Also you have to be sure to twist enough so that it is tight, but not 
too much so that the wires break.

This works best with new soft temper wire. This is normally the case for 
new building construction.  Wire that has been hardened by bending, or 
by long storage, will not twist properly.  Especially if you have one 
hard wire and one soft wire.  In this case you have to twist with 
pliers, and trim the end with cutters, and then apply the wire nut. 
Some recommend this anyway.  In this case the wire nut is merely a 
conveniently applied and retained piece of insulation.