I remember when tapping on to knob and tube we used 12-2 without gr. also. I also remember when the equipment gr. in 12-2 was a # 14, BUT that was then and This is now. AAAAAAA the days of pulling solid tw , Things are better now so should the craftmanship.Most jounreyman back then had Never even seen a code book.Back then 314.40d was not in the code book all new boxes ul listed or labeled well have a tapped hole for the gr. screw old boxes I;m sure from stock do not.
