I haven't followed this conversation,
Obviously.

Yep, I only have partial information to go on.

So far, you're the only one here who thinks it's simple, with no
major code problems.

It is not a complicated circuit, but yes there are code issues to consider.

1. It is standard practice in remodel work to extend a circuit for a new
outlet or fixture. The biggest issue I can think of would be box fill
requirements in the source box. I did mention the number of cables and size
of the box as a factor in my initial reply.

2. Wire gauge. I DID ask the OP "why" they were using 12 gauge wire.
Obviously, if the circuit is protected by a 20 amp breaker you would need
to use 12 gauge wire on that circuit (14 gauge wire could overheat before
the 20A breaker would trip). Otherwise, 14 gauge wire would be more than
adequate for an LED fixture.

3. Obviously, you can't use standard lamp cord inside a wall. You would
need to use rated cable such as Romex.

4. Connection at the lamp. Ideally the fixture would be designed for hard
wiring, with a proper cable clamp and space in the fixture to make
connections with wire nuts. Unfortunately, many undercabinet fixtures are
made to plug in. The obvious solution would be to install an outlet near
the fixture where the lamp could be plugged in. Unless the lamp
manufacturer provides a certified junction box of some type, there aren't
many low profile options that can fit under a cabinet.

My use of crimp connectors is certainly "NOT" code compliant, but done
properly it is a safe installation as long as the splice is not buried in a
wall and the cables are properly secured.

Anthony Watson
www.watsondiy.com
www.mountainsoftware.com