Feeders and branch circuits in corrosive environments must contain an insulated copper EGC sized not smaller than _____.

In corrosive environments, the National Electrical Code (NEC) specifies that equipment grounding conductors (EGC) must be appropriately sized to ensure adequate grounding and protection against electrical faults. For feeders and branch circuits in these harsh conditions, the minimum size of the insulated copper EGC should not be smaller than 12 AWG.

This requirement stems from the need to provide reliable grounding that can withstand environmental factors such as moisture, chemicals, and other corrosive agents that could deteriorate smaller or inadequately sized conductors. The sizing helps to ensure that any fault current can effectively travel through the EGC, providing a clear path to ground, and reducing the risk of electrical shock and equipment damage.

Choosing a size larger than 12 AWG, such as 10 AWG or 8 AWG, while possibly offering increased security in more severe conditions, is not mandated for the general standard in this context. However, adhering to the 12 AWG size ensures compliance with NEC requirements while being appropriate for typical corrosive environments.