In New Zealand, changing a two-pin plug to a three-pin plug sounds straightforward, but it's important to understand that this is classified as restricted electrical work under the Electricity Act 1992. In most cases, this job must be carried out by — or under the supervision of — a licensed electrician. Read on to understand exactly what the law requires, what the risks are, and what your options are.
Why the Two-Pin vs Three-Pin Difference Matters
Older New Zealand appliances and some imported equipment may come fitted with a two-pin plug (no earth pin). Modern NZ three-pin plugs include a third, longer pin — the earth (ground) pin — which provides a critical safety path for fault current, protecting you from electric shock if an appliance develops a fault. Upgrading to a three-pin plug is often the right move for safety, but it must be done correctly.
What Is Restricted Electrical Work in NZ?
Under NZ law, restricted electrical work (REW) covers most work on fixed wiring and on appliances connected to the mains supply. The Electrical Workers Registration Board (EWRB) oversees licensing of electricians and sets out what work requires a licence.
Replacing or rewiring a plug that connects to the mains (230 V) supply is considered restricted electrical work. Only a registered electrician or a person under their direct supervision may legally carry out this work. Doing it yourself without a licence is illegal and could void your home insurance, create a fire hazard, or put lives at risk.
What a Homeowner CAN Legally Do
There are a small number of electrical tasks homeowners may perform themselves in NZ. These generally include:
- Replacing a like-for-like plug on a cord-connected appliance — but only if the replacement plug is identical in type and rating, and the appliance is not a "prescribed electrical article" requiring certification.
- Changing a light bulb or fluorescent tube.
- Resetting a tripped circuit breaker or replacing a fuse in a fuse box (not rewiring it).
However, changing from a two-pin to a three-pin plug is not a like-for-like replacement — it involves a change in the plug type and potentially the wiring configuration. This takes it firmly into restricted electrical work territory. When in doubt, always check with the EWRB or a licensed electrician before proceeding.
The Risks of DIY Plug Wiring
If a plug is wired incorrectly, the consequences can be severe:
- Electric shock or electrocution — incorrect wiring can leave the appliance casing live.
- House fire — loose connections cause arcing and overheating.
- Voided insurance — insurers may decline claims if unlicensed electrical work is found to be a contributing factor.
- Legal liability — particularly important for landlords, who have obligations under the Healthy Homes standards.
What the Process Involves (For Reference)
A licensed electrician changing a two-pin plug to a three-pin will typically:
- Confirm the appliance is suitable for earthing — some double-insulated appliances (marked with a double-square symbol) are designed to run without an earth and should not have an earth connected.
- Check the cable — older two-core flex may not include an earth conductor. If there's no earth wire in the cable, the cable itself may need replacing before a three-pin plug can be correctly fitted.
- Select the correct plug — rated for the appliance's current draw (typically 10 A for most household appliances in NZ).
- Connect the wires correctly — in NZ, the standard colour coding is: Active = Brown (or Red in older wiring), Neutral = Blue (or Black), Earth = Green/Yellow.
- Secure the cord grip — so the cable cannot be pulled free from the plug body.
- Test the installation — using a plug tester or multimeter to verify correct polarity and earth continuity.
| Wire | Colour (modern NZ) | Colour (older NZ) | Terminal |
|---|---|---|---|
| Active | Brown | Red | Marked A or L |
| Neutral | Blue | Black | Marked N |
| Earth | Green/Yellow | Green | Marked E or ⏚ |
Buying the Right Plug
If a licensed electrician is doing the work, they'll source an appropriate plug. For reference, three-pin plugs conforming to the NZ/Australian standard (AS/NZS 3112) are widely available at Bunnings and Mitre 10. Always ensure any plug purchased carries the New Zealand regulatory compliance mark.
When to Call a Professional
You should call a licensed electrician any time you need to:
- Change a plug type (two-pin to three-pin, or vice versa).
- Replace damaged or frayed cord and plug assemblies.
- Wire any new plug to a mains-connected appliance.
- Assess whether an older appliance is safe to use.
A qualified local electrician can complete this job quickly, safely, and issue you with a Certificate of Compliance where required. You can find licensed electricians in your area on tradedirectory.co.nz.
A Note on Safety
Always unplug an appliance from the wall before inspecting the plug or cord. Never attempt to work on a plug while it is connected to power. If you notice a damaged plug, frayed cord, or scorch marks, stop using the appliance immediately and have it assessed by a professional.