Why RCD Protection Is Now Mandatory in NZ

3–5 minute read • Homeowners & landlords

What is an RCD?

A Residual Current Device (RCD) continuously monitors the flow of electricity. If it detects a small imbalance (e.g., current leaking to earth through a person), it trips in milliseconds — greatly reducing shock risk and fire risk.

Where are RCDs required?

Most new and altered final subcircuits supplying socket outlets and lighting in residential properties.
Areas with increased risk (bathrooms, outdoors, workshops, damp locations).
Rental upgrades and renovations typically trigger compliance checks.

RCD vs RCBO

An RCD provides earth-leakage protection only. An RCBO combines RCD + over-current/breaker in one device. For many switchboard upgrades, RCBOs are the neatest way to make each circuit individually protected.

How do I know if I’m compliant?

Open your switchboard: look for devices marked “RCD” or “RCBO” with a **test** button.
Many older boards use fuses or standard MCBs only — these usually need upgrading.
Press **TEST** monthly; the device should trip immediately. Reset afterwards.

When should I upgrade?

You’re renovating, adding new outlets/lighting, or installing a heat pump/EV charger.
You have no RCDs, or nuisance tripping suggests old/faulty devices.
You’re a landlord preparing for compliance/safety checks.

Tip: Upgrading to an RCBO-based board improves safety and makes fault finding easier because each circuit is protected and labeled.

Need help making your switchboard compliant?

We assess your current board, recommend the right RCD/RCBO layout, and handle labeling, testing, and certification.

Get a Free Quote or call 027 690 0002.