110.26 clearances

[Fred B]

What is starting point for measuring working space minimum clearances in 110.26, the outer surface of box, the inner mounting surface, or the wiring entry point? Say I have a 12"X15"X5" deep box with with multiple 120V to ground lines, I believe I meet condition 2 for table 110.26(A)(1).

 

[bwat]

Isn't this what you' re looking for?

110.26(A)(1) Depth of Working Space. The depth of the working space
in the direction of live parts shall not be less than that specified
in Table 110.26(A)(1) unless the requirements of
110.26(A)(1)(a), (A)(1)(b), or (A)(1)(c) are met. Distances
shall be measured from the exposed live parts or from the
enclosure or opening if the live parts are enclosed.

 

[infinity]

What is starting point for measuring working space minimum clearances in 110.26, the outer surface of box, the inner mounting surface, or the wiring entry point? Say I have a 12"X15"X5" deep box with with multiple 120V to ground lines, I believe I meet condition 2 for table 110.26(A)(1).

What kind of box? A junction or pull box has no minimum working space.