NEC Art. 501.10(B)(4) Boxes and Fittings

[jtinge]

Are joints, taps, and terminal connections considered non-sparking or non-arcing when applying NEC 501.10(B)(4), which does not require boxes and fittings to be explosion-proof if they do not contain any arcing devices. "Electrical Installations in Hazardous Locations", by Schram and Earley, states that non-sparking equipment includes splices in junction boxes, under the discussion of Class 1, Div 2 wiring methods. This seems to contradict the way joints, taps, and terminal connections are treated in Class 2, Div 2 environments. Can anyone shed some light on this?

 

[rbalex]

What gives you the impression that there is a contradiction?

 

[jtinge]

I was assuming that the taps, joints, and terminal connections restrictions for boxes in C2D2 locations was because these were considered to be sparking or arcing type components, but after some more investigation it appears that the restriction is related to possible presence of electrically conductive dust, not because they are sparking components. If this is the case, then I agree there is no contradiction, just confusion on my part.

 

[rbalex]

I believe the restrictions you are citing are in Section 502.10(A)(4). They apply to Class II, Division 1. The Class II, Division 2 requirements are in Section 502.10(B)(4).

Side Note: Group E (metal dusts) is always Class II, Division 1 if there are sufficent quantities to be hazardous. See Section 500.5(C)(1)(3).

 

[jtinge]

Thank you for the feedback. This and responses to posts from a few years ago answered my question.