In the RCD rating 32 A, 30 mA, AC, what does AC denote?

In the RCD rating 32 A, 30 mA, AC, what does AC denote?

• A. Alternating current
• B. Alternating current with no DC component present
• C. Analog current
• D. Active current

Answer: (B)

AC indicates the type of leakage current the device detects. It means the residual current it senses is alternating (typically the mains waveform at 50/60 Hz) and has no DC component. In other words, an AC-type RCD will trip for pure AC leakage above the 30 mA threshold, but won’t reliably detect leakage that includes DC content. If DC or pulsating DC leakage is present, you’d need Type A or Type B protection.

AC indicates the type of leakage current the device detects. It means the residual current it senses is alternating (typically the mains waveform at 50/60 Hz) and has no DC component. In other words, an AC-type RCD will trip for pure AC leakage above the 30 mA threshold, but won’t reliably detect leakage that includes DC content. If DC or pulsating DC leakage is present, you’d need Type A or Type B protection.