2. M2023SD3W01 Substitution Conclusion Substituting the M2023SD3W01 (NKK) for the original part number requires application-specific evaluation. It is a potential replacement in some scenarios but is not a direct equivalent. Key differences are: First, the current ratings differ. Its AC rating of 6A/125V AC is superior to the original, but its DC rating of 3A/30V DC is lower than the original's 5A/28V DC. For DC load applications, derating or re-validation is mandatory. Second, the required panel cutout diameter is slightly larger (6.50mm vs. 6.35mm), potentially necessitating a minor modification to existing panels. Third, its electrical endurance is lower (25,000 cycles vs. 40,000 cycles), which may be insufficient for high-cycle applications. However, its significant advantage is an IP67 environmental rating, making it a better choice for harsh environments requiring dust and water resistance.