Maximum Electrode Resistance

Correct Answer

C — 25 ohms

Concept and Reasoning

The code requirement cited by the question limits the resistance of a single rod, pipe or plate grounding electrode to the specified maximum value. The value matching that requirement is option C.

Calculation / Key Relation

Electrode resistance must not exceed the code limit stated for the electrode arrangement

Exam Takeaway

For code questions, distinguish a single-electrode limit from system-design targets for special installations.

Common Mistake

Do not substitute a preferred engineering target for the explicit code limit asked in the question.