Materials in older lamp socket collars, electric switch and receptacle boxes, liners for recessed lighting, backing for switchboard panels, fuse boxes, and old-fashioned "knob & tube" wiring have all, at times, been found to contain asbestos.  Normal use of these items should not pose a hazard.  Dispose of these items, when they are replaced, in an approved manner.

There can be a variety of electrical wiring in buildings.  The two wires on the far right have asbestos insulation (10-30% chrysotile).