lwinter31,

As one wirenut to the rest. . . [Linked Image] . . ., remember, the box was calculated (if it actually was) when devices only counted as one conductor. Deduct 4.5 in³.

The reduced ground was manufactured for compliance with the '62 NEC grounding of all receptacles, but ground wires weren't added to the volume calculation until the '68 NEC was adapted (which is also the same time that the ground wire went full sized). Deduct 1.75 in³.

The cable and BX clamps, together, count as one conductor. Add 2.25 in³.

Adjusted wire space needed: 31.25 in³.

Box capacity is adjusted be (1.) the raised cover that we don't see (in the photo above) adding an additional 7.3 in³ (from Raco catalog).

And, (2.) another interesting twist, 2002 NEC Table 314.16(A), or its equivalent, was not introduced in the NEC until '68, in a totally reworked Table 370-6(a-1). In the '62 NEC, 4" X 1½" box could hold 11 #14 conductors, implying a volume of 22 in³, see '62 NEC Table 370-6(a-1). Therefore, I suggest adding another 1.0 in³ to the box capacity.

Total box capacity = 29.3 in³.

By my calc, the box is overstuffed by 1.95 in³.

Al

Edited for '62 NEC Table 370-6(a-1)

[This message has been edited by ElectricAL (edited 01-15-2003).]

Al Hildenbrand