Only today did I realize what bothered me about this fitting. Somewhere, in a long forgotten corner of my mind, an ancient memory stirred. I realized I had encountered it. Today that memory came out of hibernation. A look at the Arlington link confirmed what I suspected.
The fittings I had encountered were similar, designed to attach to a box using a 1/2” knockout. I saw them long ago, deep within the recesses of UL’s labs. I saw them used on manufactured equipment submitted for testing. That is, the components were used in the manufacture of listed equipment — not by electricians in the field.
Look closer at the product description. They’re for use with 3/8” MC. When have you ever bought “3/8” anything? No, these are used for cables containing small gauge control wires. The sort of wires used for thermocouples, thermostats, limit switches, and the like. As such, the complete jacketed cable is pulled intact into the conduit.
True, I can recall a few times I’ve used salvaged 3/8 jackets to run ordinary wires into equipment using similar fittings. Usuall this was when I needed a cable run considerably farther than the factory supplied leads. That placed the burden of wire identification on me. I used a similar trick to provide additional protection (vermin risk) to the thermostat cable I ran along with the line set for the air conditioning.
Last edited by renosteinke; 07/20/23 10:21 AM.