Probable Effect Concentration Quotients (PECQS) Practice Test

What is the minimum size of bonding jumper conductor for aluminum in a Class I - III circuit?

1. 2.0 sq mm

2. 3.0 sq mm

3. 3.5 sq mm

4. 4.0 sq mm

The correct answer is: 3.5 sq mm

The minimum size of a bonding jumper conductor for aluminum in a Class I - III circuit is determined by the standards that govern electrical installations, specifically the National Electrical Code (NEC) or relevant industry guidelines. In this context, the use of aluminum conductors requires specific sizing considerations to ensure safety and performance, particularly when bonding to mitigate any potential electrical faults. The choice of 3.5 sq mm indicates that this size meets the necessary requirements to handle the fault currents and provide adequate conductivity while accounting for aluminum's unique properties, including its lower conductivity compared to copper. Selecting a sufficiently sized bonding jumper is crucial because it must effectively connect various conductive parts to ensure adequate grounding, protecting against electrical hazards. The other choices, being smaller than 3.5 sq mm, would not provide the same level of safety and performance when used as bonding jumpers in such circuits. They do not meet the necessary specifications for size and capacity against potential electrical loads, which are critical in ensuring compliance with safety regulations in electrical installations.