Pendant luminaires installed in Class II, Division 1 locations shall be suspended by threaded conduit stems, by chains with approved fittings, or by other approved means. Stems shall be provided with _____ or other effective means to prevent loosening.
a) set screws
b) welded joints
c) expansion joints
d) explosionproof flex
See answer and applicable Code reference
The correct answer is: a) set screws
Article 502 of the 2011 NEC covers the installation requirements for Class II locations. As outlined in a portion of Sec. 502.130(A)(3), "Pendant luminaires shall be suspended by threaded rigid metal conduit stems, by threaded steel intermediate metal conduit stems, by chains with approved fittings, or by other approved means. For rigid stems longer than 12 in., permanent and effective bracing against lateral displacement shall be provided at a level not more than 12 in. above the lower end of the stem, or flexibility in the form of a fitting or a flexible connector listed for the location shall be provided not more than 12 in. from the point of attachment to the supporting box or fitting. Threaded joints shall be provided with set screws or other effective means to prevent loosening."
