Class 2 Wire Size

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.

Class 2 wire size.

Maximum diameter of any component strand of the conductor. The maximum permissible resistance in ohms km of each conductor size class and type both plain copper and metal coated purpose of the document. A n mm 2 π 4 d n 2 0 012668 mm 2 92 36 n 19 5. Class 1 2 and 3 circuits are classified as remote control signaling and power limited circuits in the national electrical code nec.

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. 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. But remember most class 2 or 3 circuits usually are wired using listed cable types specified by the nec. Considering class 2 in a system can be an important factor for reducing the cost and improving the flexibility of the system.

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 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. The n gauge wire resistance r in ohms per kilofeet ω kft is equal to 0 3048 1000000000 times. The rules for running power circuits on a building surface in conjunction with class 2 control circuits are covered in sec.

Class 3 wiring is functionally similar to class 2 wiring but with higher voltage and power limitations. 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 minimum size circuit is 18 awg when a class 2 or 3 circuit is reclassified and used as a class 1 circuit. Conductors of class 2 and class 3 circuits shall be separated by at least 2 in.

Class 2 requirements for the power sources are also defined in the nec. Minimum number of strands required to make particular conductor size. 50 8 mm from conductors of any electric light power class 1 or nonpower limited fire alarm circuits. 60 c 140 f 75 c 167 f awg mm copper.