Fact check: What size equiment ground would you use for 200 amps when you up the wire size to 250 mcm for voltage drop

1. Summary of the results

Based on the analyses provided, for a 200-amp service using 250 MCM wire sized up for voltage drop, the equipment grounding conductor size follows specific NEC requirements:

• Base requirement: According to NEC Table 250.122, a 200-amp circuit requires a #4 AWG copper or #2 AWG aluminum/copper-clad aluminum equipment grounding conductor ^{[1] [2] [3]}
• Proportional sizing rule: Since the ungrounded conductors (250 MCM) are increased in size for voltage drop considerations (not for ambient temperature corrections, conductor fill, or adjustment for more than three current-carrying conductors), the equipment grounding conductor must be increased proportionally ^{[1] [2] [3]}
• Practical application: One analysis specifically addresses a similar scenario with a 250-foot run from a 400-amp pedestal to a 200-amp shop, recommending #2 aluminum grounding wire when using 250 kcmil aluminum conductors, or #1 aluminum if conductors are bumped up to 300 kcmil ^[4]

2. Missing context/alternative viewpoints

The original question lacks several critical pieces of information that affect the final answer:

• Wire material specification: The question doesn't specify whether the 250 MCM wire is copper or aluminum, which significantly impacts the proportional calculation ^{[1] [2]}
• Installation conditions: The analyses show that ambient temperature corrections, conductor fill, or adjustments for multiple current-carrying conductors would not require proportional upsizing of the equipment ground ^{[1] [2] [3]}
• Specific voltage drop percentage: While voltage drop is mentioned as the reason for upsizing, the target voltage drop percentage isn't specified, which could influence the final wire selection ^[5]
• Run length: The distance of the circuit run is not provided, though this is crucial for voltage drop calculations ^{[4] [5]}

3. Potential misinformation/bias in the original statement

The original question contains no apparent misinformation or bias, but it is incomplete in its technical specifications. The question appropriately recognizes that:

• Wire size may need to be increased beyond minimum ampacity requirements for voltage drop considerations
• Equipment grounding conductor sizing may be affected by this increase

However, the question would benefit from specifying the wire material, installation conditions, and target voltage drop percentage to receive a precise answer. The analyses confirm that the NEC does require proportional upsizing of equipment grounding conductors when ungrounded conductors are increased for voltage drop purposes ^{[1] [2] [3]}.