In my opinion he is incorrect. As long as the two breakers are on opposing poles of the panel buss there is no code violation until they are feeding a single yolk. If they are not feeding a single yolk device than they can be 1,3,5,7,9, etc spaces apart, but I would have them right next to each other.
#99581 - 08/17/0611:19 PMRe: multiwire circuits and tied breakers
Did you mean disposal and dishwasher ? Are you feeding a single split wired duplex receptacle with this circuit? If you are feeding a split wired duplex with this circuit you need a handle tie or a 2 pole breaker. As long as both of these circuits do not connect to a single device (yoke) you don’t need a handle tie or 2 pole breaker.
What city is this in?
#99584 - 08/18/0601:53 AMRe: multiwire circuits and tied breakers
The flat I just moved out of had this configuration- common duplex receptacle feeding a dishwasher and a disposal, two circuits, handle tied. For me, it makes sense because this way you won't run into a half-dead box assuming it's fully dead.
#99587 - 08/18/0605:38 PMRe: multiwire circuits and tied breakers
300.13 Mechanical and Electrical Continuity â€” Conductors.
(B) Device Removal. In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.
[This message has been edited by Larry Fine (edited 08-18-2006).]