Contractor is asking if a separate disconnect is required for dental x-ray machine if it has an on-off switch. NEC 517.72(A) calls for a disconnect "in the supply circuit," and 517.72(B) requires it to be "operable from a location readily accessible from the x-ray control." Is a local switch considered to be in the supply circuit? And, if so, if the control is across the room, or just outside the treatment room door, would a switch on the machine satisfy the requirement of 517.72(B)? My interpretation would be "no" and "no," but I welcome your thoughts.