Meyers Hub on NEMA 250 Type 12 enclosures

[jbolen]

I'm installing some NEMA 250 TYPE 12 indoors for dust purposes.
Question: I'm i required to used Meyers hubs on the sides of the enclosure

 

[rambojoe]

Im sure there must be some literature somewhere that ssys "all penetrations must be..." regardless, ive been called on it, with large pipe and wire installed (i think solar..)

 

[kwired]

Is this class II hazardous locations requiring "dust tightness"? If so then I'd say yes you need the hub or other sealing means and not general use dry location method of landing your raceway.

If this is just for normal atmospheric dust, then maybe the application of what you are trying to keep dust off of plays a factor but is no general requirement from NEC and normal dry location fittings should be acceptable.