Unlisted NPT Couplings

[don_resqcapt19]

Thanks,

next time i have a dlro and some spare time i will do some testing on the joints before i worry about working on a proposal. Do you have ANSI FB-1 for couplings? i cannot find free access to this. if you have it, is the testing even very extensive at all? i would guess just checking coating thickness, length and probably a compression test and maybe a go no go thread measurement.

I do not have access to that.

 

[Wire-Smith]

I just remembered why I first thought of npt couplings a couple years ago. You have a much narrower tight range with npsm, this is nothing for straight runs but with bends you have to line your bend up and I would approximate with npsm you only have 180 degree of tight range, if you go over that your damaging the threads which isn't a huge deal unless you go a degree too far, if you loosen it back up a degree after overtightening the joint is loose. I have run across a lot of loose conduit joints because of this. Npt joints such as hubs and condulets I say you have a tightening range of 360 degree. As you know a loose conduit joint is more likely to be a bad electrical connection and if you throw in some corrosion which the joint will be more susceptible to, then you lost your connection.