On Sun, 1 Apr 2007 05:41:27 +0000 (UTC), (Don
Klipstein) wrote:

In article , Just Joshin wrote:
On Mon, 26 Mar 2007 11:01:56 -0600, Chris Friesen
wrote:

Em wrote:
I added 14-gauge (15A) romex cable to a circuit that had 12-gauge (20A)
wire, indicating I had made a mistake, but it turns out to be a 15A breaker
on the circuit with 12-gauge wire. Is that OK/safe? I don't have to correct
my mistake, right? Thanks

Correct. However, if the #12 wire goes to the panel you may end up
confusing the next person looking at the electrical system--they may
assume that since it's #12 wire its safe to put a 20A breaker on the
circuit, not realizing that the circuit includes some #14..

Chris

Some AHJ would have you lable the circuit 15amp only.

I have before seen a municipality's code webpage saying that it is
against code to have a branch circuit having wires differing in allowed
breaker amps. However, I did not find it clear whether that was NEC or a
local building code.

I'm fairly sure that NEC only requires you to size the breaker for
the smallest wire in the sequence. I'll admit I can see the point
in wanting them all to be the same, though, because it would be
easy for someone to look at the wire leaving the service panel,
notice that it's 12 AWG, and up the breaker to 20A.



If you have mixed size wiring in a branch circuit, I would equalize it
if possible. If not, I would have visible tags everywhere the larger
wiring would be seen saying that the branch circuit is a mixed wire size
circuit and what the breaker amps should be - and hope the home inspector
does not see that being a problem when you sell the house.

Personally, I think there should be no permanently installed wiring
thinner than 12 in a house, as common as 20 amp breakers and fuses are.