Class 3 Power Limited Circuit Cable

The limited power and voltage of these circuits is what makes them a separate and specialized wiring method.

Class 3 power limited circuit cable.

The following graph shows a comparison of nec class 2 i max limits with ul 60950 limited power circuit requirements. These circuits are designated class 1 2 and 3 not to be confused with the class i ii and iii hazardous locations an entirely different matter. A class 1 circuit is the portion of the wiring system between the load side of the overcurrent protection device ocpd or the power limited supply and the connected load. The maximum circuit voltage is 30vac and 60vdc for a class 2 power source limited by overcurrent protection and 150vac or vdc for a class 3 power source limited by overcurrent protection.

A listed class 2 or class 3 transformer. The power supply connected to a class 1 2 or 3 circuit for the most part determines the class of that circuit. Also can be used in security and audio applications. Remember that the class 2 or 3 circuit begins at the power supply.

725 41 the power source for a class 2 or a class 3 circuit must be one of the following. The minimum size circuit is 18 awg when a class 2 or 3 circuit is reclassified and used as a class 1 circuit. Mini split wire is a class 3 power limited circuit cable used with hvac mini split systems. Equipment supplying class 2 or 3 circuits must be marked to indicate each circuit that is a class 2 or 3 circuit 725 42.

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 nec in article 725 makes a sharp distinction between wiring for ordinary power and light circuits and specialized circuits where the power and or voltage is limited. Tray cable is a multi conductor control signal or power cable rated for 600 volts. Listed information technology equipment.

For example heating system thermostats are commonly class 2 systems and the majority of small bell buzzer and annunciator systems are class 2 circuits. Equipment listed as a class 2 or class 3 power source amplifier for audio program signals. This article will help distinguish the differences between these circuits. Also class 1 remote control circuits are limited up to 600 volts with no other.

Option 2 listed class 2 power supply is easier to achieve than option 4 limited power circuit acc. That means conductors and equipment on the supply side of the class 2 or 3 power source must be installed in accordance with chapters 1 through 4 725 51. May be installed in raceways conduit cable trays and. A listed class 2 or class 3 power supply.

For example class 1 power limited circuits are supplied by a power supply with an output that does not exceed 30 volts and 1 000 volt amps.