On Sun, 26 Jan 2014 11:32:20 -0500, wrote:

On Sun, 26 Jan 2014 08:06:37 -0800 (PST), Harry K
wrote:

On Saturday, January 25, 2014 10:46:53 AM UTC-8, wrote:
On Sat, 25 Jan 2014 10:06:13 -0800 (PST), Harry K

On Saturday, January 25, 2014 7:07:01 AM UTC-8, wrote:
On Saturday, January 25, 2014 9:55:33 AM UTC-5, (PeteCresswell) wrote:
I've got an outlet box that is fed by #12 Romex backed by a 20-amp
breaker.
If I were to tap that box to feed a ceiling light, would #14 wire be
code-legal for box-to-ceiling-light?

No, unless you change the breaker to 15 amps.

That also should not be code compliant as someone could see the 12 guage wire coming off the breaker and change it back to 20amp.
Harry K

What code is that? The NEC does not address what an unqualified person
might do later.

NEC code does not even address anything about WHO wires it. Ever hear about getting wiring inspected when selling a house? Violations don't pass no matter who screwed it up.

Harry K

Not exactly true.

90.1(C)
(C) Intention. This Code is not intended as a design specification or
an instruction manual for untrained persons.
The NEC is intended for use by capable engineers and electrical
contractors in the design and/or installation of electrical equipment;
by inspection authorities exercising legal jurisdiction over
electrical installations; by property insurance inspectors; by
qualified industrial, commercial, and residential electricians; and by
instructors of electrical apprentices or students.
That just says who it ( the code) is intended to be used by - and
does not say anything about who does the work. ( as long as the
installation is inspected by " inspection authorities exercising legal
jurisdiction over electrical installations")