This implies that there is a limit on a 250.122 EGC and/or that it should be upsized after a certain point. Where is this stated other than the generic catch all about having an efffective low impedence fault path (or whatever the actuall wording is - its still raining and the codebook is still out in the truck
)
Does anyone know how/why it was decided that female rigid threads would not be tapered?
it's not a question of taper as much as class of fit. if you take a condulet, it has a tapered fitting,
but it's looser than a plumbing fitting.
male npt threads are all cut to the same pitch diameter. if you use a go/nogo thread gauge,
it'll have two ground marks on it. hand tight, the end of the pipe needs to be between those
two marks.
same with female fittings, except that with the electrical fittings, the thread doesn't have any
taper, but when you screw in a go/nogo gauge, it needs to bottom out between the witness marks.
either with a tapered or straight female thread.
a plumbing fitting is designed to go on hand tight about two turns, so you can have a WOG tight
fitting with several turns still left for orientation, or total length.
not that any pipe factory in china actually possesses a set of guages to set their equipment to. :rant::rant::rant:
