Changing a standard single switch to a two-way switching setup — so you can control a light from two different locations — is a popular home improvement, especially for hallways, staircases, and large rooms. However, in New Zealand, most of this work is restricted electrical work and must be carried out by a registered electrician. Here's what you need to know before you pick up a screwdriver.
Understanding Two-Way Switching
A standard (one-way) switch simply breaks or completes a single circuit. A two-way switch has three terminals — a common terminal and two traveller terminals — allowing two switches to control the same light fitting from different positions. The wiring between the two switch positions requires an additional conductor (often called a strappers wire or traveller wire), which means new cable may need to be run through walls or ceilings.
This is the key reason why this job is almost always restricted work in NZ: it typically involves working inside the wiring system, not just swapping a fitting.
What Is Restricted Electrical Work in New Zealand?
Under the Electricity Act 1992 and associated regulations, restricted electrical work (REW) covers any work on fixed wiring in your home — including adding, altering, or extending circuits. This includes:
- Running new cable between two switch positions
- Connecting wires to switch terminals that are part of the fixed wiring
- Any work inside a switchboard
Only a registered electrician (or a person under their direct supervision) can legally carry out REW. After completing the work, they must issue you an Electrical Safety Certificate. You can verify a tradesperson's registration with the Electrical Workers Registration Board (EWRB).
Safety note: Working on live or incorrectly isolated circuits can cause electrocution or fire. Even if you feel confident, the legal and safety risks of DIY fixed wiring in NZ are significant.
What a Homeowner Can Legally Do
As a homeowner, you are permitted to do very limited electrical work on your own home (not a rental). This generally includes:
- Replacing a like-for-like switch on an existing circuit — for example, swapping a faulty standard switch for an identical standard switch, without altering any wiring
- Changing a light bulb or a plug-in appliance
However, converting from a one-way to a two-way switch is not a like-for-like replacement. It requires different wiring, additional cable, and changes to the circuit — all of which are REW. Even if you purchase the correct two-way switch plates from Bunnings or Mitre 10, the installation itself must be done by a licensed sparky.
How the Job Is Done (What Your Electrician Will Do)
Understanding the process helps you have an informed conversation with your tradesperson:
1. Isolate the Circuit
The electrician will switch off the relevant circuit breaker and confirm the circuit is dead using a multimeter or voltage tester before touching any wiring.
2. Assess the Existing Wiring
They'll open the existing switch box to check what cable is already present and whether there is a suitable route to run a new cable to the second switch location.
3. Run New Cable
A three-core-and-earth cable (or two separate two-core cables, depending on the method used) is typically run between the two switch positions. In older homes, this may involve lifting floorboards or fishing cable through wall cavities.
4. Install Two-Way Switches
Both switch plates are wired with the correct connections at the common and traveller terminals. The switches are then fitted into their wall boxes.
5. Test and Certify
The electrician tests the circuit, confirms correct operation from both switch positions, and issues an Electrical Safety Certificate — which you should keep with your home's records.
Choosing the Right Switch
Two-way switch plates are widely available in NZ. When selecting one, consider:
| Feature | What to Look For |
|---|---|
| Style | Match your existing switches (standard, grid, slimline) |
| Colour | White, black, brushed steel, etc. |
| Brand compatibility | Clipsal, HPM, PDL are common NZ brands |
| Smart options | Some two-way smart switches require a neutral wire — check with your electrician |
Your electrician can advise on compatibility with your existing wiring and wall boxes.
Do You Need a Building Consent?
For a straightforward switch upgrade, a building consent is generally not required. However, the electrical work still requires an Electrical Safety Certificate as noted above. If you're unsure, check with your local council. The MBIE Building Performance website has useful guidance on what work requires consent.
When to Call a Professional
You should always hire a registered electrician for this job. Converting a standard switch to a two-way switch involves altering fixed wiring, which is restricted electrical work under NZ law. Attempting it yourself (or using an unregistered person) is illegal, may void your home insurance, and creates a genuine risk of electrocution or electrical fire.
A qualified local electrician can be found on tradedirectory.co.nz. Always ask to see their EWRB registration and request an Electrical Safety Certificate on completion.
Sources & Further Reading
- Electrical Workers Registration Board (EWRB) — verify electrician registration
- MBIE Building Performance — building consent guidance
- WorkSafe NZ — electrical safety information
- BRANZ — NZ building and construction research
- Bunnings NZ — switch and electrical fittings
- Mitre 10 NZ — electrical accessories
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