What subsection I do not see it?Panel flush with wall, no violation. Recessed, 110.26 violation.
need to be accessible to "shut off" by service personnel and non-service personnel, in emergencies.Could be argued that it is only accessible to service personnel except, for OSHA compliance requirements?
Did you read the exceptions for existing res?(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 live parts or from the enclosure or opening if the live parts are enclosed."
3' from the front of the enclosure needs to be clear.....Flush, good, recessed, bad...
The exception is only good for less height......you still can’t place a panel like the drawing you provided.Did you read the exceptions for existing res?