Shortcircuit IMO extending that circuit is not allowed by Rule 3 of our (MA) 527 CMR 12:00: 2005 MEC.
Rule 3. Additions or modifications to an existing installation shall be made in accordance with this Code without bringing the remaining part of the installation into compliance with the requirements of this Code. The installation shall not create a violation of this Code, nor shall it increase the magnitude of an existing violation.
I do not know anyway you can add to this circuit and meet the new code.
As an example can you add a grounding receptacle to a K&T system?
Also IMO the NEC will not allow what you are asking about, the new location for the range is just that a new
location / installation.
IMO existing as used by NEC 250.140 exception means where it is now, not where you want to move it.
[This message has been edited by iwire (edited 02-19-2005).]