As long as the circuit is protected by a 15 Amp breaker, it's fine. If it's on a 20 Amp breaker, you should either change the wiring for the entire circuit so it's all 12 ga or change the breaker to a 15 Amp.

 

I agree with HotRodx10 and I would also add that if leaving the 14 gauge wire in place I would label the breaker as having 14 gauge wire. Later someone might see the 12 gauge wire on the breaker and assume that the circuit can handle 20 amps.

 

The breaker is a 20… so looks like i keep the wiring all 12.

 

Generally, changing the breaker would easier than running new wire to replace the 14 ga, but if you want a 20 Amp circuit there, then changing out the 14 ga for 12 ga works. Just make sure you change out all the 14 ga wiring on that breaker.

 

What you describe was common at one time. It is a misapplication of the tap rules. I would let sleeping dogs lie. It is a code violation but not particularly dangerous.

 

I agree with your statement, but i am remodeling and changing lights so might as well make it up to code.

 

They are considering a code change due to this. Its going to say basically,,, if it leaves the panel with 12 its got to stay 12 and cant do that anymore and with good reason.

 

I have seen it, fools the maint and the handyman. Havnt seen the language but can use a 12 in the middle but not at the start with the 15 breaker.

 

Yes general overheating IS the issue,,, these circuits may have multiple outlets . Aint gonna mean squat to a rodent.

 

I agree with niles on this, a violation but not a real big deal especially on fixed equipment and not on circuits with outlets.
I opened up a kitchen fixture a while back,,, had a 16 lamp cord for a switch loop. I still wonder about the installer,,, was he being a slug or really understand theory well enuf to know its true risk?

 

The draw is the main issue in this sense and for this crowd. Nothing in the code says its rated for rodent chew or really says much about a pinched wire and circuits above 30 even allow smaller ground wires as does most of the equipment connected to 20A circuits.
The whole system is based on the connected load. "The expected electrical draw of the fixture is not the main issue, the main issue is protecting the wire from overheating if something unexpected happens."
The design of the connected equipment protects the wire or the wire is sized to carry the load with a safety factor and really the only time the breaker provides thermal is circuits with multiple outlets. Having said that,,,, not that it wont open on thermal but its not to be used as a thermal limiting device for circuit design. You can wire a 30 circuit with 14 wire,, not to an outlet but to equipment with an exception to outlet for welders.
I mention this in another thread, saw it a while back, wasnt a real big deal was to light fixtures.

 

UL listed equipment must have design to limit thermal to legally connect to the grid. Might be as simple as wire size. Might be a fuse like modern xmas lights. Maybe thermal like a power strip has,, protects those outlets from heat but the circuit breaker is still the fault protection,,, the pinched wire/clamp situation.

 

The welding machine is designed so it wont overheat the listed circuit wire for it,,, the motor must have 125% wire,, and maybe its own thermal, the breaker may be 2x the common wire size etc.

 

Electric range is a good example. The equipment within is sized to carry its load, the 6 cord is designed not to overheat with the combined loads and the breaker is designed to fault all those parts (pinched wire) and to allow the combined loads to pass without tripping on thermal.