B&G 3A Practice Test 2025 – Comprehensive Exam Prep

A Class A Ground Fault Circuit Interrupter (GFCI) is designed to provide a high level of protection against electrical shock by monitoring the leakage current to ground. Specifically, a Class A GFCI is required to trip when it detects a ground fault current of 6 milliamperes (mA) or greater.

This threshold of 6mA is chosen because it provides an adequate balance between safety and nuisance tripping. At this level, the GFCI can effectively protect individuals from the risk of electrical shock, as currents above this threshold can cause serious harm, especially in residential or wet locations where there is a higher risk of contact with water.

In contrast, other values, such as 4mA, 10mA, or 15mA, do not meet the established requirement for Class A devices. The 4mA threshold is too low for reliable safety measures, as it may lead to nuisance tripping, while the 10mA and 15mA levels would not provide the necessary protection against electrical shock as effectively as the established 6mA trip level. Therefore, the correct answer reflects the safety standards set for Class A GFCI devices.