As for the thread specification ... many factory-made electrical parts have straight threads, rather than tapered. That's not the issue. The NEC specifies tapered threads for "field made" threads ... which I consider applies to any threads you make, or have made.
Now why would they want a tapered plumbimg thread if you have a all the proper die sets, to make stright threads, did anyone ever notice how bushings and locknuts, used on tapered ends are loose, and tapered threads in manufactured products are sloppy, all i can see it they allow it for all the cheap penny pinching EC's that will not buy the proper tools, or tool manufactures must of decided they could save money and increase profits, by only making one set of tapered tools, so they lobbied for the change.
