Class 3 Power Limited Circuit Cable

A listed class 2 or class 3 transformer.

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. 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 tray cable 600 volt. 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. May be installed in raceways conduit cable trays and. 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 limited power and voltage of these circuits is what makes them a separate and specialized wiring method.

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. Equipment supplying class 2 or 3 circuits must be marked to indicate each circuit that is a class 2 or 3 circuit 725 42. 725 41 the power source for a class 2 or a class 3 circuit must be one of the following. 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.

Equipment listed as a class 2 or class 3 power source amplifier for audio program signals. For example heating system thermostats are commonly class 2 systems and the majority of small bell buzzer and annunciator systems are class 2 circuits. The power supply connected to a class 1 2 or 3 circuit for the most part determines the class of that circuit. 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.

Nec class 2 i max limits versus ul60950 limited power circuits 0v 5v 10v 15v 20v 25v 30v 35v 40v 45v 50v 55v 60v 65v. But remember most class 2 or 3 circuits usually are wired using listed cable types specified by the nec. Remember that the class 2 or 3 circuit begins at the power supply. 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.

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. Listed information technology equipment. A listed class 2 or class 3 power supply. Tray cable is a multi conductor control signal or power cable rated for 600 volts.

Mini split wire is a class 3 power limited circuit cable used with hvac mini split systems.