electricallighting
I want to hang a vertical pendant, but what do I do to prevent the wire from pulling through? The vertical cord is a hard nylon that can carry the vertical load of the pendant, and the hole in the pendant is small enough for only the wire to pass through. If I make an underwriter's knot, the wire will not slip through and the pendant will hold.
But what is an alternative for this knot, as making it from the hard cord is rather difficult?
In the case that the lamp is light weight enough to not stress the cord, there's a specific knot for that called an Underwriter's Knot that is supposed to put minimum stress on the conductors and provide enough bulge to keep it from pulling out. Since most PVC insulation will cold flow under pressure, the edges it butts up against must be well rounded.
First off you do not want to hang the light by the socket that you purchased. With the poke in holes for the wires this is NOT an acceptable mounting system for your lamp - heavy glass or not.
Next note that the wire used to hang lamps is a special type that has strengthing cord built into the cable.
The conventional hanging lamp fixture has a two piece socket assembly that has a top part that slides up on the cord. The cord is then knotted with a special electricians knot that puts equal tension in all the conductors and fibres in the cord. The ends of the wires then attach to the lower portion of the conventional socket via screw terminals. Finally the top and bottom parts of the socket firmly snap together to hide the knot inside. The hanging lamp assembly pulls against the knot to transfer the weight into the cord from the ceiling.
Best Answer
If it is a fairly lightweight fixture, you could try a zip tie or two around the cord. This may not work depending on how hard the cord is and how heavy the lamp is. But I have used them with light weight pendants and cords that had some flex so the zip tie could squish the sheath a bit to keep it from slipping.
Another option, if there is enough space, is to use a Waterproof Cable Gland they tighten onto the cord and depending on the cord material may not slip. But there may not be enough space for one. I seem to recall having a pendant light once that had something like this built into it to allow the height to be adjusted.