Oklahoma Electrical Practice Exam

What is the maximum allowable transformer secondary current for lighting systems operating at 24v, excluding class II conductors?

1. 15 amps

2. 20 amps

3. 25 amps

4. 30 amps

The correct answer is: 25 amps

In electrical systems, especially in the context of lighting and power distribution, it's essential to adhere to specific standards and limitations to ensure safety and functionality. In the case of a transformer supplying a lighting system operating at 24 volts, the maximum allowable secondary current is determined by various factors, including the wire size, insulation type, and the applicable NEC (National Electric Code) regulations. The correct choice indicates that the maximum allowable secondary current can go up to 25 amps. This is significant because it reflects the practical limitations placed on the transformers used in such systems to prevent overheating and potential failure. Transformers and associated conductors can handle a certain amount of current based on their design and the current carrying capacity of the conductors used in the system. This choice also aligns with safety measures that prevent overheating and ensure that the circuit can handle the load without significant voltage drop or damage to the system. These ratings are particularly important in applications such as lighting where consistent voltage is critical for performance. The other choices present higher values that would not comply with safety and regulatory standards for the conductors or system designed for 24 volts, potentially leading to inefficiencies or hazards in the installation. Thus, a maximum of 25 amps is established as a safe and effective limit for lighting