Texas Fire Alarm License Practice Test

What voltage rating is marked on P.F.L.A cables?

1. No specific rating

2. Not less than 150 volts

3. Not less than 300 volts

4. Not more than 600 volts

The correct answer is: Not less than 300 volts

P.F.L.A (Power-Limited Fire Alarm) cables are specifically designed for use in fire alarm systems and are regulated to ensure safe operation. The correct voltage rating marked on these cables is not less than 300 volts. This rating is critical because it indicates the cable's ability to safely contain the voltage levels typically found in fire alarm systems without risk of breakdown or failure. The 300-volt rating is a standard established to meet safety requirements while allowing for adequate performance of the fire alarm systems under various conditions. When considering other ratings, cables marked with a lower voltage rating like less than 150 volts or less than 300 volts would not be appropriate for fire alarm applications, as they may not provide enough assurance for safety and performance under normal operating conditions. A rating exceeding 600 volts would also not be suitable for P.F.L.A. cables, as it exceeds the necessary specifications for fire alarm systems, which are designed to operate safely and effectively within the lower voltage range. Thus, the marking of not less than 300 volts ensures that the fire alarm cables can handle the requirements of the system they are intended to support.