Class 2 Wire Size

The rules for running power circuits on a building surface in conjunction with class 2 control circuits are covered in sec.

Class 2 wire size.

This class 2 wire conforms to national electrical safety standards for in wall lighting installation and comes in 16 awg and 18 awg american wire gauge. The nec defines such circuits as that portion of the wiring system between the load side of the overcurrent protection device ocpd or the power limited supply and all connected equipment. Considering class 2 in a system can be an important factor for reducing the cost and improving the flexibility of the system. The tables below are intended to be a general guide for wire size and amp ratings.

Maximum diameter of any component strand of the conductor. 50 8 mm from conductors of any electric light power class 1 or nonpower limited fire alarm circuits. But remember most class 2 or 3 circuits usually are wired using listed cable types specified by the nec. The n gauge wire s cross sercional area a n in square millimeters mm 2 is equal to pi divided by 4 times the square wire diameter d in millimeters mm.

Class 2 requirements for the power sources are also defined in the nec. 60 c 140 f 75 c 167 f awg mm copper. Minimum number of strands required to make particular conductor size. Class 1 2 and 3 circuits are classified as remote control signaling and power limited circuits in the national electrical code nec.

The wire size chart below shows allowable ampacities of insulated conductors rated up to and including 2000 volts 60 c through 90 c 140 f through 194 f not more than three current carrying conductors in raceway cable or earth directly buried based on ambient air temperature of 30 c 86 f. The n gauge wire resistance r in ohms per kilofeet ω kft is equal to 0 3048 1000000000 times. Especially when the voltage level of the control circuits is shifted from ac 120v to a dc voltage with 24v class 2 could be applicable. A n mm 2 π 4 d n 2 0 012668 mm 2 92 36 n 19 5.

Conductors of class 2 and class 3 circuits shall be separated by at least 2 in. Ul 13 standard for safety for power limited circuit cables which lists 30 awg as the smallest for class 2 and 24 awg for class 3. The in wall rated wire is the best option for this low voltage lighting configuration and is perfect for large or small remodels and upgrades. Major differences in the installation of class 2 wiring are that conductor sizes 18 and 16 awg are permitted and splices such as with wire nuts are permitted outside of conventional enclosures.