Electrical wiring rules: AS/NZS 3000 on site

What a builder needs to know about AS/NZS 3000 — RCD protection, keeping power away from water, and who certifies the work.

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Electrical work sits outside the Building Code — it’s governed by the Electricity Act and the Electrical (Safety) Regulations 2010, with AS/NZS 3000 (the Wiring Rules) as the technical standard. It must be done by a registered electrician (EWRB), and two ideas matter most on site: RCD protection, and keeping electricity away from water.

RCD and MEN — the safety backbone

An RCD (residual current device) trips in milliseconds if current leaks to earth — for example, through a person. The Wiring Rules require 30 mA RCD protection on socket outlets and lighting in homes. The whole installation references earth through the MEN (multiple earthed neutral) system, which is what makes that fast trip reliable.

All socket-outlet circuits ≤32A must be RCD-protected (30 mA trip).
Cooktop and hot water circuits are also RCD-protected on most modern installations.
The MEN system is mandatory in NZ — neutral and earth are bonded at the switchboard.
An earth electrode is driven into the ground at the switchboard; resistance is tested per AS/NZS 3000.

Electricity around the bath and shower

The principle is simple: keep power outlets out of and away from the bath and shower area — the closer to water, the tighter the restriction.

Inside and directly above the bath or shower, only extra-low-voltage (SELV) fittings are allowed; ordinary power outlets are not.
Fixed appliances near the wet area — heated towel rail, extract fan, light — must be RCD-protected and suitably IP-rated (splash or immersion resistant) for their position.
All socket-outlet circuits in the bathroom must be RCD-protected regardless of position.

AS/NZS 3000 sets the exact zone boundaries, dimensions and minimum IP ratings — we don’t reproduce that table. Have a registered electrician confirm the layout.

Common wiring rules and heights

Standard NZ supply is 230V single-phase and 400V three-phase (per the 2025 amendment, from the older 240/415V designation).
Switches in habitable rooms sit 1000–1300mm above the floor (G1/AS1 plus accessibility).
Power outlets are typically 250mm above a bench and 300mm above the floor.
Smoke alarms are hardwired on a dedicated lighting circuit with a 10-year battery backup.
Keep working space of ≥600mm clear in front of the switchboard (AS/NZS 3000 §1.7.7).

Certification — who signs it off

Only a certified electrician can do prescribed electrical work. On completion they issue the paperwork that proves the install is compliant.

An Electrical Safety Certificate (ESC) is required for all consented work.
A Certificate of Compliance (CoC) is issued at completion — and an ESC is issued for high-risk work.

Plain-English guide, not advice. This page helps you understand and navigate the rules — it is general information, not design, engineering or consent advice, and it does not reproduce the copyrighted tables of NZS 3604 or any Standard. Always check the current Standard or Acceptable Solution and your BCA, and use a suitably qualified LBP, engineer or QS where it matters.

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Common questions

Does electrical work fall under the Building Code?

No. Electrical work sits outside the Building Code — it’s governed by the Electricity Act and the Electrical (Safety) Regulations 2010, with AS/NZS 3000 (the Wiring Rules) as the technical standard. It must be done by a registered electrician (EWRB).

What RCD protection do the Wiring Rules require in a home?

AS/NZS 3000 requires 30 mA RCD protection on socket outlets and lighting in homes. All socket-outlet circuits ≤32A must be RCD-protected with a 30 mA trip, and cooktop and hot water circuits are also RCD-protected on most modern installations.

Can you put a power outlet inside or above a bath or shower?

No. Inside and directly above the bath or shower, only extra-low-voltage (SELV) fittings are allowed — ordinary power outlets are not. Fixed appliances near the wet area must be RCD-protected and suitably IP-rated, and all bathroom socket-outlet circuits must be RCD-protected regardless of position.

What certificates does an electrician issue?

A Certificate of Compliance (CoC) is issued at completion, and an Electrical Safety Certificate (ESC) is required for all consented work and is issued for high-risk work. Only a certified electrician can do prescribed electrical work.

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