TPS cable is one of the most commonly used cable types in New Zealand electrical installations. But with sizes including 1.0mm², 1.5mm², 2.5mm², 4.0mm² and 6.0mm², selecting the right cable requires more than simply matching a cable size to an application.
For electrical contractors, cable selection needs to consider the requirements of the individual circuit, installation conditions, current-carrying capacity, voltage drop, protective devices and applicable New Zealand electrical requirements.
This guide provides a practical overview of common TPS cable sizes and the types of applications in which electricians may encounter them.
What Is TPS Cable?
TPS stands for tough plastic sheathed cable.
It is widely used in New Zealand residential and commercial electrical installations. TPS typically contains insulated conductors enclosed within an outer protective sheath and is available in different conductor sizes and configurations depending on the application.
Electricians commonly encounter TPS cable when working on lighting, socket outlets, general power circuits and other fixed wiring installations.
TPS Cable Size Comparison
The table below provides a general overview of common TPS cable sizes and applications.
| Cable size | Common applications* |
|---|---|
| 1.0mm² TPS | Lighting, switching and selected lower-current circuits |
| 1.5mm² TPS | Lighting and selected fixed-wiring applications |
| 2.5mm² TPS | General power and socket-outlet circuits |
| 4.0mm² TPS | Selected higher-load and dedicated circuits |
| 6.0mm² TPS | Selected higher-current circuits, equipment and submain applications |
Important: This table provides general examples only and should not be used as a cable-sizing specification. Appropriate cable size depends on the individual installation.
Electrical contractors should consider factors including design current, installation method, current-carrying capacity, voltage drop, ambient conditions, grouping and derating factors, protective-device requirements, manufacturer information and applicable New Zealand electrical standards and regulations.
1.0mm² TPS Cable
1.0mm² TPS is commonly associated with lighting and other suitable lower-current applications.
Its smaller conductor size can make it convenient to work with where the electrical design and installation conditions allow its use.
However, the application alone should never determine conductor size. Installation method, circuit design and other relevant factors still need to be considered.
Common applications may include:
- Lighting circuits
- Switching
- Selected lower-current fixed-wiring applications
1.5mm² TPS Cable
1.5mm² TPS is another cable size commonly encountered by New Zealand electricians, particularly in lighting and selected fixed-wiring applications.
Compared with 1.0mm² cable, the larger conductor may provide additional capacity depending on the installation conditions and cable specification.
Common applications may include:
- Lighting circuits
- Switching
- Selected fixed-wiring circuits
- Applications requiring a larger conductor than 1.0mm² where supported by the circuit design
The final selection should always be based on the requirements of the circuit rather than cable size alone.
2.5mm² TPS Cable
2.5mm² TPS is widely used in general electrical work and is commonly associated with socket outlets and general power circuits.
For many electrical contractors, it is one of the core cable sizes regularly required for residential and light-commercial projects.
Common applications may include:
- General power circuits
- Socket outlets
- Residential electrical installations
- Selected commercial applications
Again, 2.5mm² should not automatically be assumed to be suitable for every power circuit. Installation conditions, circuit load, cable length, protective devices and other design considerations can affect the required conductor size.
4.0mm² TPS Cable
4.0mm² TPS may be selected for higher-load or dedicated circuits where the electrical design requires a larger conductor.
Applications may include:
- Selected dedicated circuits
- Higher-load equipment
- Longer cable runs where appropriate
- Other circuits where the design requires a larger conductor than 2.5mm²
The suitability of 4.0mm² cable depends on the specific circuit and installation conditions.
6.0mm² TPS Cable
6.0mm² TPS is commonly considered for selected higher-current applications.
Depending on the electrical design, this may include dedicated equipment circuits or certain submain applications.
Applications may include:
- Selected higher-current circuits
- Dedicated equipment
- Selected submains
- Other applications requiring increased conductor capacity
Equipment such as EV chargers, cooking appliances and other significant electrical loads are sometimes associated with larger cable sizes. However, 6.0mm² should not automatically be assumed to be the correct cable size for these applications.
The required conductor size needs to be determined from the actual equipment, circuit design, installation method, cable length, protective device and other relevant factors.
1.5mm² vs 2.5mm² TPS: What's the Difference?
The obvious difference is conductor cross-sectional area.
A larger conductor can generally carry more current under equivalent conditions, but cable selection isn't based on conductor size in isolation.
For example, an electrician comparing 1.5mm² and 2.5mm² TPS should also consider:
- Circuit design current
- Installation method
- Cable grouping
- Ambient temperature
- Thermal insulation
- Voltage drop
- Protective device
- Cable manufacturer specifications
- Applicable electrical requirements
This is why saying "1.5mm² is for lighting and 2.5mm² is for power" can be a useful generalisation but isn't a substitute for proper circuit design.
2.5mm² vs 4.0mm² TPS
The same principle applies when comparing 2.5mm² and 4.0mm² TPS.
A circuit with a higher design current may require a larger conductor, but load is only part of the calculation.
Cable length and installation conditions can also influence the appropriate conductor size.
A larger cable may sometimes be selected to manage voltage drop or installation conditions even where the connected load alone might suggest a smaller conductor.
4.0mm² vs 6.0mm² TPS
For higher-load applications, contractors may find themselves comparing 4.0mm² and 6.0mm² TPS.
The correct choice depends on the circuit.
Considerations can include:
- Maximum demand and design current
- Circuit length
- Installation method
- Current-carrying capacity
- Voltage drop
- Grouping and derating
- Protective-device characteristics
- Equipment manufacturer's requirements
Rather than selecting 6.0mm² simply because an application is considered "high load", the conductor should be selected based on the actual installation requirements.
What Determines the Correct TPS Cable Size?
There isn't one cable size that is automatically correct for every application.
Several factors can affect cable selection.
Design Current
The expected current of the circuit is a fundamental consideration when determining conductor size.
Installation Method
How and where the cable is installed can affect its ability to dissipate heat.
Cable installed in different environments can therefore have different current-carrying capabilities.
Derating Factors
Conditions such as grouping, ambient temperature and thermal insulation may affect the allowable current-carrying capacity of a cable.
Voltage Drop
Voltage drop becomes particularly important on longer cable runs and can influence conductor selection.
A conductor may need to be increased in size even where its basic current-carrying capacity appears sufficient.
Protective Device
Cable selection and circuit protection need to work together. The characteristics of the protective device form part of the overall circuit design.
Manufacturer Information
Contractors should use the relevant technical information for the actual cable being installed rather than relying solely on general rules of thumb.
Is TPS Cable Suitable for New Zealand Electrical Installations?
TPS is widely used in New Zealand electrical installations, but contractors should ensure the particular product selected is appropriate for its intended application and meets applicable requirements.
Product specifications and relevant compliance documentation should be checked before installation.
CoreGrid360 supplies electrical cable intended for the New Zealand market and makes relevant product information and compliance documentation available where applicable.
What TPS Cable Sizes Does CoreGrid360 Supply?
CoreGrid360 supplies a growing range of Dominion Cables TPS cable for New Zealand electrical contractors.
Our range includes common conductor sizes such as:
Check individual product listings for current specifications, configurations, availability and pricing.
Buy TPS Cable Online in NZ
CoreGrid360 is an Auckland-based online electrical wholesaler supplying electrical contractors throughout New Zealand.
We believe contractors should be able to see what they're paying without unnecessary complexity.
That's why we're building CoreGrid360 around transparent, competitive online pricing for electrical products.
Whether you're purchasing cable for everyday work or pricing materials for a larger project, you can browse our TPS cable range online and see current product pricing.
Ordering Larger Quantities?
If you're buying TPS cable for a larger job or require multiple rolls, send us your materials requirements.
Request project or volume pricing from CoreGrid360.
Frequently Asked Questions About TPS Cable
What does TPS mean in electrical cable?
TPS stands for tough plastic sheathed cable. It is a commonly used form of fixed electrical wiring in New Zealand.
What is 2.5mm² TPS cable commonly used for?
2.5mm² TPS is commonly associated with general power and socket-outlet circuits. However, the correct conductor size depends on the circuit design and installation conditions.
Can 1.5mm² TPS be used for lighting?
1.5mm² TPS is commonly encountered in lighting applications. Suitability for a particular circuit still needs to be determined according to the actual installation requirements.
Is 6.0mm² TPS suitable for an EV charger?
It may be suitable for some installations, but cable size for an EV charger cannot be determined from the equipment type alone. Charger load, circuit length, installation method, voltage drop, derating, protective devices and manufacturer requirements can all affect cable selection.
Does a longer cable run affect cable size?
It can. Longer cable runs can increase voltage drop, which may influence conductor selection.
Where can electricians buy TPS cable online in New Zealand?
CoreGrid360 supplies TPS cable online to electrical contractors throughout New Zealand. Contractors can view online pricing and product specifications or request pricing for larger project quantities.
Shop TPS Cable from CoreGrid360
Need cable for your next job?
Browse the CoreGrid360 TPS cable range and compare available sizes, specifications and transparent online pricing.
Buying in volume?
Important Information
This article provides general information for electrical professionals and is not a substitute for electrical design, manufacturer instructions, applicable standards or regulatory requirements.
Cable selection should be determined for the specific installation by an appropriately qualified person in accordance with applicable New Zealand legislation, standards and requirements.