GRC needs two (2) locknuts at each connection, unless the terminus is hubbed.
And don't forget your ( plastic ) bushings, too. I'm amazed at how often they're forgotten.
( GRC nipples require bushings across the entire range of wire sizes. 344.46 )
This also applies to running threads.
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That you are even spending one second on this line of inquiry -- is a miss-application of time.
One does NOT make it in the trades by trying to value engineer out locknuts.
It is in the nature of the beast that electrical contractors always have a surfeit of said locknuts since so many connectors end up terminating in PVC female adapters. ( F/As )
Hence, locknuts hold nothing but Scrap Value -- particularly now that China is exporting steel fittings on the cheap.
