Class 1, Div 1, Groups C & D Wiring Question 1

[elfman]

I work in the Wastewater industry and we are often designing controls for such environments. I was talking to a fellow Controls Engineer and he made a comment I don't know if I agree with. We often run full voltage wiring out to the hazardous area in permanent conduit to a junction box then transition to flexible cord (SO) rated for the hazardous area with proper seal fittings, etc. This junction box has always been designed in the past as a NEMA 7 box with just a terminal strip inside to facilitate the connections. This other gentleman indicated that we do not need to put that terminal strip in a NEMA 7 box but rather just a NEMA 4X box because it these are passive connections. This doesn't sound right to me. Seems like if I am running full voltage - typically 480 3 Phase - I should need to have the NEMA 7 box for the JB. What should/can we be doing and be safe and meet code? Thanks.

"To be or not to be, that is the question" - William Shakespeare via Hamlet

 

[wroggent]

To my knowledge, NEMA 7 for Div 1, and NEMA 4 is sometimes ok for Div 2.

501.10(A)(3) "All boxes and fittings shall be approved for Class I, Division 1" -i.e. NEMA 7

501.10(B)(4) applies to Division 2

If your system was intrinsically safe then you could use general purpose enclosures...