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Standards & safety

Type A vs Type B RCD — what your EV charger actually needs.

An RCD is meant to cut power the instant current leaks to earth. Not all RCDs detect all leakage. Here is the difference between Type A and Type B, and why EV charging changes the answer.

In preparationThe full write-up is in progress. The outline below is the structure the finished piece will follow.

Outline

  1. 01

    The three leakage waveforms: AC, pulsed DC, smooth DC

  2. 02

    Type AC, A, F, B — what each catches

  3. 03

    Why EV chargers produce smooth DC leakage

  4. 04

    The consequence: a Type A RCD can 'blind' on an EV fault

  5. 05

    What Basis uses and why

  6. 06

    What the NZ wiring rules (AS/NZS 3000) require today