Which class of circuit connects the load side of the Class 2 power source to the connected equipment?

The correct answer is Class 2. Class 2 circuits are designed to provide power to devices within the fire alarm system while ensuring a level of safety that is appropriate for low-voltage applications. These circuits are limited in their output, which helps to minimize the risk of electric shock and reduces the thermal and fire hazards that can occur with higher voltage systems.

Class 2 circuits also have specific restrictions; they are typically powered by a Class 2 power source that provides a maximum of 100 VA (volt-amperes), which is sufficient for operation without presenting the same risks as higher class circuits. It is important because these characteristics make Class 2 circuits ideal for connecting devices such as fire alarm initiators and notification appliances.

In contrast, other classes of circuits, such as Class 1, Class 3, and Class 4, either allow for higher power output, involve different regulations regarding power supply and load connections, or are generally used for different applications that do not ensure the same level of safety and limitations as Class 2 circuits. Understanding the distinctions between these classes is crucial for ensuring compliance with national and local codes while ensuring the reliability and safety of fire alarm system installations.