In order to keep a hanging pendant light from falling through the cover plate in the ceiling I tied a knot in the electric wire, as a stopper. Is this safe, or did I just create a fire hazard? If it's unsafe, what can I use as a stopper on the electrical wire of a pendant light?
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.