ECN Forum Forums Code Related Discussion NEC & other Code issues Article 514 (514.11) Circuit Disconnects

The logic may be flawed but if they really want the grounded conductor opened, it sounds like that is not happening.

As a guy who spent most of my life chasing transients, a safer option would be to ground all of the conductors but that is not what the code says.

The requirement is somewhat archaic. As with a great deal of Article 514, Section 514.11(A) was originally extracted fom NFPA 30 or one of its successor documents. The current parallel text in NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages is no longer as stringent. (See Section 6.7)
The text does reflect the general anathema Articles 500 through 516 hold for multiwire branch circuits and not quite so obvious the fairly stringent bonding requirements in Classified locations. (They want absolutely no possible path for a potential ground fault) The text may be due for editing.