of higher ratings. The overcurrent device shall be permitted to be an integral part of the power source.

III. Control Circuit Wiring Methods.

522.20 Conductors, Busbars, and Slip Rings. Insulated control circuit conductors shall be copper and shall be permitted to be stranded or solid. Listed multiconductor cable assemblies shall be permitted.

Exception No. 1: Busbars and slip rings shall be permitted to be materials other than copper.

Exception No. 2: Conductors used as specific-purpose devices, such as thermocouples and resistive thermal devices, shall be permitted to be materials other than copper.

522.21 Conductor Sizing.

(A) Conductors Within a Listed Component or Assem- bly. Conductors of size 30 AWG or larger shall be permitted within a listed component or as part of the wiring of a listed assembly.

(B) Conductors Within an Enclosure or Operator Sta- tion. Conductors of size 30 AWG or larger shall be permitted in a listed and jacketed multiconductor cable within an enclosure or operator station. Conductors in a non-jacketed multiconductor cable, such as ribbon cable, shall not be smaller than 26 AWG. Single conductors shall not be smaller than 24 AWG.

Exception: Single conductors 30 AWG or larger shall be permitted for jumpers and special wiring applications.

(C) Conductors Outside of an Enclosure or Operator Station. The size of conductors in a listed and jacketed, multiconductor cable shall not be smaller than 26

AWG. Single conductors shall not be smaller than 18
AWG and shall be installed only where part of a
recognized wiring method of Chapter 3.

522.22 Conductor Ampacity. Conductors sized 16 AWG and smaller shall not exceed the continuous current values provided in Table 522.22.

522.23 Overcurrent Protection for Conductors. Conduc- tors 30 AWG through 16 AWG shall have overcurrent protection in accordance with the appropriate conductor ampacity in Table 522.22. Conductors larger than 16 AWG shall have overcurrent protection in accordance with the appropriate conductor ampacity in Table 310.16.

522.24 Conductors of Different Circuits in the Same

Cable, Cable Tray, Enclosure, or Raceway. Control cir-

Table 522.22 Conductor Ampacity Based on Copper Conductors with 60°C and 75°C Insulation in an Ambient Temperature of 30°C

Ampacity

Conductor Size

WG) 60°C 75°C

30 - 0.5

28 - 0.8

26 - 1

24 2 2

22 3 3

20 5 5

1. For ambient temperatures other than 30°C, use Table 310.16 temperature correction factors.

2. Ampacity adjustment for conductors with 90°C or greater insulation shall be based on ampacities in the 75°C column.

cuits shall be permitted to be installed with other circuits as specified in 522.24(A) and (B).

(A) Two or More Control Circuits. Control circuits shall be permitted to occupy the same cable, cable tray, enclosure, or raceway without regard to whether the individual circuits are alternating current or direct current, provided all conductors are insulated for the maximum voltage of any conductor in the cable, cable tray, enclosure, or raceway.

(B) Control Circuits with Power Circuits. Control cir- cuits shall be permitted to be installed with power conductors as specified in 522.24(B)(1) through (B)(3).

(1) In a Cable, Enclosure, or Raceway. Control circuits