I have three way switches at the top and bottom of my stairs. There is a light at the top of the stairs controlled by the switches and I wish to add a light at the bottom.
A 14/2 runs first to the light at the top (hot and neutral from the breaker), then a 14/2 runs to the switch at the top (hot supply and switched hot back to the light), and a 14/3 runs between the switches (travelers and switched return).
It would be very difficult to run a new 14/2 (switched hot and neutral) from the light upstairs to the light downstairs, but it is easy to run a 14/2 from the downstairs light to the switch box downstairs.
I want to know if it is acceptable to connect the hot switched from the downstairs 3 way to the light and run a separate neutral to the breaker box, or another nearby circuit's neutral.
skill level: electrical engineer / homeowner, but not an electrician. (know how to not burn the house down, but don't know the electrical code)