M Q wrote:

Pete C. wrote:

... To contain the wiring mess a
ground bar can be installed in the pull box with a larger single ground
conductor returning to the new panel. The neutrals all have to go back
to the new panel individually as do the hots.

I am curious about the requirement for the neutrals to all go back to
the main panel individually. It is not immediately obvious to me
why that would need to be. Do you know the rational and/or the
electrical code section?

Don't have a code reference handy, but an obvious reason is that GFCI
and the newly required AFCI circuit breakers require the circuit neutral
to connect through them.