INSULATING FITTINGS FOR ELECTRICAL MACHINES, APPLIANCES OR EQUIPMENT, BEING FITTINGS WHOLLY OF INSULATING MATERIAL APART FROM AN MINOR COMPONENTS OF METAL (FOR EXAMPLE, THREADED SOCKETS) INCORPORATED DURING MOULDING SOLELY FOR THE PURPOSES OF ASSEMBLY, OTHER THAN INSULATORS OF HEADING 8546, ELECTRICAL CONDUIT TUBING AND JOINTS THEREFOR, OF BASE METAL LINED WITH INSULATING MATERIAL