Probable Effect Concentration Quotients (PECQS) Practice Test

What is the minimum size of conductor required for grounding of an instrument transformer?

1. 2.5 sq. mm

2. 3.5 sq. mm

3. 4.5 sq. mm

4. 5.5 sq. mm

The correct answer is: 3.5 sq. mm

The minimum size of conductor required for grounding an instrument transformer is crucial because it ensures safety and proper functioning of the electrical system. Grounding provides a path for fault currents to return to the ground, helping to prevent electrical shock and equipment damage. The standard requirement for the minimum size often varies based on set regulations and practices, but generally, a conductor size of 3.5 sq. mm is deemed adequate for this purpose. This size is considered to provide sufficient conductivity and mechanical strength to handle fault conditions, ensuring reliable operation while also adhering to safety standards. In comparison, some of the other options may not meet the regulatory requirements for grounding purposes, either being too small to handle potential fault currents or lacking in adequate conductivity, which is essential in minimizing voltage drop and ensuring effective grounding. Thus, the selected size of 3.5 sq. mm balances safety, performance, and compliance with electrical standards.