Porcelain cleats in a conduit spacer bar saddles box.
Part of the Bob Gray collection of electrical objects.
Electrical wiring needs to be held in place and these cleats were a quick, cheap, and easy way to do this job, especially in industry. Many early electrical installations were surface mounted using cleats like these. These cleats are made of porcelain which is non-conductive. Porcelain was a popular material for many types of electrical insulators until the 1930s when thermosetting plastics such as Bakelite started to take their place. By the 1930s a greater emphasis on electrical safety meant that cables for industry were enclosed in steel conduit or trunking. These cleats probably ended up in a spacer bar saddle box when they were taken out of service by electrician Bob Gray during a re-wiring job.