npt threaded junction box

[profkefah]

hello

its my first nthread here
we requested self start device
so company replied with detail
in specification

junction box
has 1.5 inch NPT female hub

ok

question


what npt mean exactly
i red in internet
it mean National Pipe Thread

so what that mean

any photo
thank u in advance

 

[electrofelon]

I assume they just mean a threaded hub, such as a "Myers hub". If we are being precise, I believe most/all hubs will be NPS or straight threads. I am not sure if anyone makes a true tapered thread (NPT) hub.

 

[kwired]

See this page

Most all NEC covered raceways are either directly threaded with NPT threads or use fittings with NPT dimensions. Most fittings however use a straight thread instead of a tapered thread but have very close to same diameter and thread pitch otherwise.

If you have something made to IEC standards it will normally have different size and thread pitch than something made to NEMA standards.

 

[don_resqcapt19]

I assume they just mean a threaded hub, such as a "Myers hub". If we are being precise, I believe most/all hubs will be NPS or straight threads. I am not sure if anyone makes a true tapered thread (NPT) hub.

As far as I know the female threads on a conduit hub are NPT and listed for use with the NPT male threads on conduit.

 

[kwired]

As far as I know the female threads on a conduit hub are NPT and listed for use with the NPT male threads on conduit.

Myers hubs in particular may or may not have taper to them, but I believe are intended/listed for inserting tapered thread and technically are not suitable for straight thread to be inserted. I think same goes for most FS type boxes and conduit body hubs. Many still use them with straight thread conduit fittings quite often though

 

[mtfallsmikey1]

Myers hubs are NPT, we've used them on our cooling towers for screw-in heating elements