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Thursday, January 14, 2021
Question:
Charlie Trout Flash Back Question:
Hello,
Can the grounded neutral conductor be smaller than the ungrounded service conductors when it is supplied a 3-phase, 3-wire, corner-grounded delta system?
A
Answer:
Charlie Trout Flash Back Answer:
First, I’m a bit confused; it doesn’t take much these days. In a corner-grounded, 3-phase, 3-wire system, there is no neutral. I’ll answer the question on that basis. The answer is the grounded service conductor for this system must be the same size as the largest ungrounded phase conductors. Remember that the grounded conductor must also meet the identification requirements in 200.6 and overcurrent protection is generally not permitted in accordance with 240.22. NEC Reference: 250.24(C)(3)