tray.

(2) Class 1 circuit conductors and power-supply conduc- tors not functionally associated with the Class 1 circuit conductors shall be permitted to be installed in a cable tray without barriers where all of the conductors are installed with separate multiconductor Type AC, Type MC, Type MI, or Type TC cables and all the conductors in the cables are insulated at 600 volts.

725.49 Class 1 Circuit Conductors.

(A) Sizes and Use. Conductors of sizes 18 AWG and 16

AWG shall be permitted to be used, provided they
supply loads that do not exceed the ampacities given in
402.5 and are installed in a raceway, an approved
enclosure, or a listed cable. Conductors larger than 16
AWG shall not supply loads greater than the ampacities
given in 310.15. Flexible cords shall comply with Article
400.

(B) Insulation. Insulation on conductors shall be suitable for 600 volts. Conductors larger than 16 AWG shall comply

(A) Power Source. The power source for a Class 2 or a Class 3 circuit shall be as specified in 725.121(A)(1), (A)(2), (A)(3), (A)(4), or (A)(5):

FPNNo. 1: Figure 725.121 illustrates the relationships
with Article 310. Conductors in sizes 18 AWG and 16 AWG
between Class 2 or
Class 3 power sources, their
shall be Type FFH-2, KF-2, KFF-2, RAF, PAFF, PF, PFF, PGF, PGFF, PTF, PTFF, RFH-2, RFHH-2, RFHH-3, SF-2, SFF-2, TF, TFF, TFFN, TFN, ZF, or ZFF. Conductors with other types and thicknesses of insulation shall be permitted if listed for Class 1 circuit use.

725.51 Number of Conductors in Cable Trays and

Raceway, and Derating.

(A) Class 1 Circuit Conductors. Where only Class 1 cir-

supply, and the Class 2 or Class 3 circuits.
FPN No. 2: Table 11(A) and Table 11(B) in Chapter 9 provide the requirements for listed Class 2 and Class
3 power sources.

(1) A listed Class 2 or Class 3 transformer

(2) A listed Class 2 or Class 3 power supply

(3) Other listed equipment marked to identify the Class

2 or Class 3 power source

Exception No. J to (3): Thermocouples shall not require

cuit conductors are in a raceway,
the number of

listing as a Class 2 power source

conductors shall be determined in accordance with
300.17. The derating factors given in
310.15(B)(2)(a)

Power source—

725.121(A)(1)

through (A)(4)

shall apply only if such conductors carry continuous
loads in excess of 10 percent of the ampacity of each
conductor.

(B) Power-Supply Conductors and Class 1 Circuit Con- ductors. Where power-supply conductors and Class 1

Supply (0 to 600

Power source—

725.121(A)(1)

through (A)(4)

circuit conductors are permitted in a 725.130 Part III of Article 725
raceway in accordance with 725.48, the number of conductors shall be
determined in

volts ac or dc)

•ftr Power source— M

accordance with 300.17. The derating factors given in
310.15(B)(2)(a) shall apply as follows:

725.121(A)(1)

through (A)(4)

(1) To all conductors where the

Class 1 circuit
conductors carry continuous loads in excess of 10

I ' 725.127

percent of the ampacity of each
conductor and
where the total number of conductors is more than
three