300.20(B) Where a single conductor carrying alternating current passes through metaql with magnetic properties, the inductive effect shall be minimized by ... passing all the conductors in the circuit an insulating wall sufficiently laqrge for all the conductors of the circuit.
Don't "knob and tube" methods violate this rule? Each wire, in loom, enters a box in its own hole, yes?
In any event, it looks like whoever did this had once seen "knob and tube" described in some book, and made a "scientific wild ass guess" (SWAG) based on that with this install.
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