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6mA DC Protection to IEC 62955

Overview

PlugStream includes built-in protection that trips the output if a residual direct current (DC) of 6 mA is detected.
This protection complies with IEC 62955:2018 [1], which defines the requirements for an RDC-DD (Residual Direct Current Detecting Device).

Standard Requirements

IEC 62955 requires that the RDC-DD protection is tested under two conditions:

  • Sudden appearance of DC (Clause 9.9.2.1)
  • Gradual (ramped) increase of a smooth DC component (Clause 9.9.2.2)

Ambiguity in Testing

The requirements for the ramped DC test are not precisely defined.
As a result, test instruments from different manufacturers may produce different outcomes when evaluating the same device.

This inconsistency has led to updates in test equipment — for example, Metrel (a leading manufacturer of electrical test devices) issued a software update to ensure more consistent results when testing RDC-DDs.

Key Takeaway

PlugStream’s built-in 6 mA DC protection meets IEC 62955 requirements.
However, when testing, installers may see variation depending on the test equipment used — particularly in ramped DC tests. Always ensure your test set is running the latest firmware/software for reliable results.