A farm building is being wired, and a grounding electrode system is required. The soil resistivity is found to be very high. Which of the following grounding electrode arrangements would be most effective in achieving a low resistance to ground?

Question: A farm building is being wired, and a grounding electrode system is required. The soil resistivity is found to be very high. Which of the following grounding electrode arrangements would be most effective in achieving a low resistance to ground?

Answer options:

• A single driven ground rod, 2.4 m (8 ft) in length.
• A metal water pipe electrode, if available and compliant. ✅ Multiple ground rods driven 3.0 m (10 ft) apart and bonded together.
• An isolated concrete-encased electrode.

Correct answer: Multiple ground rods driven 3.0 m (10 ft) apart and bonded together.

Explanation: Where soil resistivity is high, using multiple ground rods spaced at least 3.0 m (10 ft) apart and bonded together significantly reduces the overall resistance of the grounding electrode system, as per CEC Rule 10-904. A single rod may not achieve the desired resistance, and while a water pipe is good, its availability is not guaranteed. Isolated electrodes are generally not preferred for general grounding.