This would be an improper application of electrical technology from the first days of Edison introducing the three wire concept.
Yes! it was a code violation in all the years of publication, of any code.
Connect the 14 guage wire to 15 amp breakers, make sure the black and red conductor of each cable is on opposite buss connections at the panel.
The 15 amp breakers can be single pole, in most cases, if supplying outlets and lighting.
[This message has been edited by Bennie R. Palmer (edited 03-22-2001).]