Class 3 Power Limited Circuit Cable

Also class 1 remote control circuits are limited up to 600 volts with no other.

Class 3 power limited circuit cable.

725 41 the power source for a class 2 or a class 3 circuit must be one of the following. A listed class 2 or class 3 power supply. 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. Tray cable is a multi conductor control signal or power cable rated for 600 volts.

This article will help distinguish the differences between these circuits. May be installed in raceways conduit cable trays and. 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. 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.

Remember that the class 2 or 3 circuit begins at the power supply. 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 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 listed as a class 2 or class 3 power source amplifier for audio program signals. Also can be used in security and audio applications. Option 2 listed class 2 power supply is easier to achieve than option 4 limited power circuit acc. 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.

A listed class 2 or class 3 transformer. Equipment supplying class 2 or 3 circuits must be marked to indicate each circuit that is a class 2 or 3 circuit 725 42. The following graph shows a comparison of nec class 2 i max limits with ul 60950 limited power circuit requirements. But remember most class 2 or 3 circuits usually are wired using listed cable types specified by the nec.

Mini split wire is a class 3 power limited circuit cable used with hvac mini split systems. 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. Mini split tray cable 600 volt.

The minimum size circuit is 18 awg when a class 2 or 3 circuit is reclassified and used as a class 1 circuit.