Wiring clarifacation

[Sean Fogarty]

Its been a long day so my mind is fried. I know this is a simple one but just to be sure.

Living room lights added in ceiling. Circuit is 20amp 12G and junctioned in attic, then ran to the lights.
Added wiring from junction boxes to lights is 15 amp 14 g.. Either the wiring needs replaced or the breaker needs to be changed correct...

[Larry D. Kage]

Yes, 14 guage wire on a 20 amp circuit doesn't get it.

[Sean Fogarty]

Thank you Larry!

[Robert Meier]

Yes, the general rule is that a #14 AWG conductor must be protected at not more than 15 amps {240.4(D)(3)} so in this case the OCPD would need to be changed to 15 amps. But there are exceptions, for example fixture wires tapped to a light fixture can be protected at greater ampacites. Even #18 AWG conductors can be tapped to a 20 amp circuit. Not sure that this would apply to this installation but this is good as a point of reference.

240.5 Protection of Flexible Cords, Flexible Cables, and Fixture Wires.
Flexible cord and flexible cable, including tinsel cord and extension cords, and fixture wires shall be protected against overcurrent by either 240.5(A) or (B).
(A) Ampacities. Flexible cord and flexible cable shall be protected by an overcurrent device in accordance with their ampacity as specified in Table 400.5(A) and Table 400.5(B). Fixture wire shall be protected against overcurrent in accordance with its ampacity as specified in Table 402.5. Supplementary overcurrent protection, as covered in 240.10, shall be permitted to be an acceptable means for providing this protection.
(B) Branch-Circuit Overcurrent Device. Flexible cord shall be protected, where supplied by a branch circuit, in accordance with one of the methods described in 240.5(B)(1), (B)(3), or (B)(4). Fixture wire shall be protected, where supplied by a branch circuit, in accordance with 240.5(B)(2).
(1) Supply Cord of Listed Appliance or Luminaire. Where flexible cord or tinsel cord is approved for and used with a specific listed appliance or luminaire, it shall be considered to be protected when applied within the appliance or luminaire listing requirements. For the purposes of this section, a luminaire may be either portable or permanent.
(2) Fixture Wire. Fixture wire shall be permitted to be tapped to the branch-circuit conductor of a branch circuit in accordance with the following:
(1) 20-ampere circuits — 18 AWG, up to 15 m (50 ft) of run length
(2) 20-ampere circuits — 16 AWG, up to 30 m (100 ft) of run length
(3) 20-ampere circuits — 14 AWG and larger
(4) 30-ampere circuits — 14 AWG and larger
(5) 40-ampere circuits — 12 AWG and larger
(6) 50-ampere circuits — 12 AWG and larger

[Sean Fogarty]

Good point to bring up..
I was not sure if the wires just fed the lights only or continued to feed the rest of circuit. If it was just one added fixture at the end or off a junction would it still need to be 12g or could you use 14 if it were just a single light??

[Larry D. Kage]

How are fixture wires defined as opposed to branch circuit conductors?

[Sean Fogarty]

I know I am overthinking, just curious. Why would an 18 gauge lamp cord be sufficent, but a 14 g pigtail to feed a light fixture not acceptable??

[Jim Port]

The entire run needs to be sized for the OCPD. you cannot have the #14 on the 20 amp circuit, regardless of it's position in the circuit.

The load on the fixture wires is finite. That is why the smaller conductors are allowed.

The load on the branch circuit conductors is limited only be the OCPD. Smaller conductors like the #14 in this example could overheat before the breaker tripped.

[Robert Meier]

To determine if a conductor is rated as a fixture wire it would need to listed as per Table 402.3. As Jim stated the load on the fixture wire is limited by the fixture so smaller conductors are permitted to be tapped and protected by a larger OCPD. The load cannot exceed the values in Table 402.5.

ARTICLE 402 Fixture Wires
402.1 Scope.
This article covers general requirements and construction specifications for fixture wires.
402.2 Other Articles.
Fixture wires shall comply with this article and also with the applicable provisions of other articles of this Code.
FPN: For application in luminaires, see Article 410.
402.3 Types.
Fixture wires shall be of a type listed in Table 402.3, and they shall comply with all requirements of that table. The fixture wires listed in Table 402.3 are all suitable for service at 600 volts, nominal, unless otherwise specified.

402.5 Allowable Ampacities for Fixture Wires.
The allowable ampacity of fixture wire shall be as specified in Table 402.5.
No conductor shall be used under such conditions that its operating temperature exceeds the temperature specified in Table 402.3 for the type of insulation involved.
FPN: See 310.10 for temperature limitation of conductors.

Table 402.5 Allowable Ampacity for Fixture Wires

Size (AWG)- Allowable Ampacity
18_____________6
16_____________8
14_____________17
12_____________23
10_____________28

[Sean Fogarty]

Robert,
You are always helpful in finding the answers. I greatly appreciate it..

[Frank P. Newman]

I seem to recall that #14 is ok for the switch leg on a 20A lighting circuit. True?

[Larry D. Kage]

Originally Posted by fnewman

I seem to recall that #14 is ok for the switch leg on a 20A lighting circuit. True?

No...

Originally Posted by Jim Port

The entire run needs to be sized for the OCPD. you cannot have the #14 on the 20 amp circuit, regardless of it's position in the circuit.

Smaller conductors like the #14 in this example could overheat before the breaker tripped.

[Robert Meier]

Originally Posted by fnewman

I seem to recall that #14 is ok for the switch leg on a 20A lighting circuit. True?

As Larry said, no. Although I've heard that this is a common installation practice in some places.