Does anyone happen to know when the code started requiring a certain length of wire at j-boxes? I'm dealing with existing cloth bx and changing fixtures/devices and trying to apply a practical approach.
In old work, from a practical sense, it is what it is. Talk to your AHJ to see what remediation they like there. Typically you can splice on the additional conductor necessary to make the box usable but that is not defined in the code.
Not to change directions here but are you allowing grounding type receptacles? I have often wondered about this, as the BX provides a grounding path, although questionable and not actually listed for grounding. What do you do?
BigB: Best answer I can offer is: "320.108 Equipment Grounding Conductor. Type AC cable shall provide an adequate path for fault current as required by 250.4(A)(5) or (B)(4) to act as an equipment grounding conductor." From the '11 NEC