In an RFC test (R1+R2), what should the value equal?

In an RFC (Residual Fault Current) test, when measuring the combined resistance of the phase and neutral conductors (R1 + R2), the expectation is that this measurement can be used to assess the efficacy of earth fault protection. The correct approach is to take the total resistance value (R1 + R2) and then divide it by a factor to derive a suitable reference point for fault current evaluation.

The division by four is grounded in practical electrical engineering principles that account for various factors influencing fault current, such as the impact of the system’s impedance and effective connections. By dividing by four, the result provides a more accurate representation for determining the expected fault current in a safe and effective manner.

This division ensures that safety margins are accounted for, reflecting real-world conditions and enabling reliable protective device operation. The focus is not solely on averaging the resistances, but on contextualizing the resistance measurement within the framework of effective fault protection in electrical systems. Thus, the correct option reflects a practical understanding of electrical safety and system design standards.