Twin and Earth cable is a fundamental component in electrical systems, playing an integral role in domestic building wiring. They are the ones that act whenever we flick switches and power devices. Join us for an in-depth look at this popular electrical wire.
What is twin and earth cable specification?
Twin and Earth cable, often abbreviated to “T&E” cable, is a type of flat fixed cable that is known for its simplicity and reliability. It typically consists of two PVC-insulated copper conductors and one ground conductor. While standard t&e cables are typically insulated and sheathed with PVC, LSF twin and earth cable is also a popular choice for they give off less smoke and fewer toxic gases when burned.
Twin & earth cable is used for indoor fixed electrical installations; it is not designed to withstand severe mechanical abrasion, should not be installed where there is no additional mechanical protection and where frequent movement is required, and must be physically supported at regular intervals with twin and earth cable clips during installation. This cable is also known as 6242y cable. (in Australia, it’s referred to as TPS cable).
Below, let’s summarize some of the specific applications of twin and earth cables from the above information.
What is twin and earth cable used for?
Due to the lack of UV radiation and moisture protection, flat twin and earth cables are generally not suitable for outdoor use, but are used indoors for dry and fixed electrical installations (in walls, ceilings, or conduits). Common applications are as follows:
- Lighting Circuits: When wiring light fixtures, twin core and earth cable’s two insulated conductors carry the live and neutral currents, while the earth conductor provides a safety ground. It connects switches, fixtures, and dimmers of the lighting system, allowing users to control and illuminate the building.
- Socket Circuits: Twin and Earth cables can be used to power wall sockets and other similar outlets in homes, businesses, and other buildings, allowing users to plug in and use their electrical devices.
- Appliance Circuits: Twin and Earth cable wire fixed appliances such as ovens, electric heaters, and immersion heaters, ensuring that these appliances receive the necessary power to operate safely.
- Two-Way or three-way Switching: The additional core in 3 core Twin and Earth cable makes it available for two-way or three-way switching configurations, allowing users to control lights or outlets from multiple locations.
- Ring Circuits: In some regions, it’s common to use twin and earth cables in ring main circuits, which provide more capacity and better safety than a simple radial circuit, ensuring even distribution of power throughout a room.
- Junction Boxes: Twin and earth cable is also used to connect junction boxes (also known as fuse boxes or breaker panels). Junction boxes serve as points where multiple cables come together to branch or extend circuits. Twin and earth wires connect junction boxes to the electrical supply to provide safe power distribution throughout the building.
It’s worth noting that the specific usage of twin and earth cables may vary depending on local electrical codes and regulations. Additionally, the cable’s size also varies to suit the load requirements.
Identifying twin and earth cable sizes.
Twin and earth cables are typically used in low-voltage applications; load capacity (provided below), cable length, and cable size are the main factors to consider. For longer cable runs, thicker conductors are often needed to reduce resistance and maintain a stable voltage level. As far as cable size is concerned, the following table demonstrates the diameter, resistance, and specific application of different cross-sectional areas of two-core and three-core T&E cables:
Twin and Earth Cable Size Chart | ||||||
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Nominal Section (mm²) | Number of Conductors | Top-limit of Overall Diameter (mm) | Maximum DC Resistance(20℃)(Ω/km) | Minimum Insulation Resistance at 70℃ (MΩ.km) | Reference Weight(kg/kmm) | Application |
2x0.75 | 1 | 4.6x7.1 | 24.5 | 0.012 | 42 | Light-duty applications like lamps. |
2x1.0 | 1 | 4.8x7.4 | 18.1 | 0.011 | 49 | Suitable for lighting circuits, smoke alarms, and similar low current applications. |
2x1.5 | 1 | 5.3x8.5 | 12.1 | 0.011 | 65 | Indoor lighting circuits. |
2x2.5 | 1 | 6.2x10.1 | 7.41 | 0.010 | 97 | Often used for socket outlets, immersion heaters, and wall heaters. |
2x4 | 1 | 6.7x11.1 | 4.61 | 0.0085 | 140 | Small electric appliances like ovens and larger heaters. |
2x6 | 1 | 7.5x12.5 | 3.08 | 0.0070 | 192 | Larger electrical appliances such as electric showers and rice cookers. |
2x10 | 2 | 9.5x16.2 | 1.83 | 0.0065 | 306 | High power applications, like cooking appliances and central heating circuits. |
3x0.75 | 1 | 4.6x9.6 | 24.5 | 0.012 | 60 | Used in two-way lighting circuits or control circuits. |
3x1.0 | 1 | 4.8x10.1 | 18.1 | 0.011 | 70 | Suitable for lighting circuits with more than one switch or for applications requiring a third conductor for specific purposes. |
3x1.5 | 1 | 5.3x11.7 | 12.1 | 0.011 | 95 | Common size for domestic circuits, can be used in ring main circuits or radial circuits. |
3x2.5 | 1 | 6.2x14.0 | 7.41 | 0.010 | 142 | Used in larger domestic and light commercial applications |
3x4 | 1 | 7.0x15.8 | 4.61 | 0.0085 | 213 | More extensive lighting circuits with multiple fixtures |
3x6 | 1 | 7.5x17.5 | 3.08 | 0.0070 | 284 | Connecting high-power appliances, hot tubs, or electric vehicle charging stations. |
3x10 | 2 | 9.5x23.0 | 1.83 | 0.0065 | 457 | High power applications, like HVAC systems, and commercial kitchen equipment |
As can be seen easily from the above table common twin & earth cable sizes range from 1mm to 10mm or larger, with 1 mm to 2.5 mm being solid-core cables and larger being stranded-core electrical cables. The thicker the cable diameter, the more copper it contains and the heavier it is. Now that we’ve covered cable sizes, let’s look at the ratings of T&E cables.
Twin and Earth Cable Ratings
The rating of a twin and earth cable refers to the maximum current ( in amperes) that the cable can safely carry, and is largely dependent on the cross-sectional area of conductors and installation methods (in-wall conduit mounting or direct clamping). Below are typical current ratings of different T&E cable sizes:
- Twin and earth cable 1mm: 5 – 16 Amps.
- 5 mm twin and earth cable: 14.5 – 20 Amps.
- 5mm twin and earth: 20 – 27 Amps.
- Twin and earth cable 4mm: 26 – 37 Amps.
- Twin and earth cable 6mm: 32 – 48 Amps.
- Twin and earth cable 10mm: 44 – 64 Amps.
In summary, cable ratings stipulate the performance of cables and are critical to their safe use. The cable size chosen should be able to handle a slightly larger load than your equipment to ensure that the cable will operate efficiently without overheating or voltage drop issues. And installation methods and temperatures (T&E cables are rated from -5°C to +75°C) should also be carefully evaluated to ensure the safety and reliability of your electrical installations. Finally, let’s check out the color coding of T&E cable.
In summary, selecting the proper ratings for your electrical requirements is critical to safe operation, and current capacity, voltage rating, conductor size, etc. must be carefully evaluated to ensure the reliability and security of your electrical installations. Finally, let’s check out the color coding of T&E cable.
Twin and earth cable Colours
The conductors of T&E cables are usually color-coded to aid in identification and simplify installation. Color coding varies by region and time, but common standards are as follows:
- Live/Phase Wire: also known as hot wire, is typically brown, serves to transfer current from the power source to the device.
- Neutral Wire: is typically blue, which carries the electrical current back from the device or appliance to the source.
- Earth or ground Wire: is usually either bare copper or covered with green-and-yellow insulation. In the event of a fault, this wire provides a safe path for the current and helps prevent electrocution by safely directing the current to earth.
- Sheath color: generally gray or white, and can be customized as per customer’s requirement.
In a three-core twin and earth, the additional live wire is typically black. Failure to follow the correct color-coded wiring can be a safety hazard, making it critical to distinguish the color coding in accordance with local codes correctly.
Learn More: Understanding Electrical Cable Colours: Codes And Roles
Bottom Line
All in all, twin and earth cables are essential to fixed electrical installations. Their simple yet effective design makes them a preferred choice for both domestic and commercial wiring tasks. Choosing the correct cable size based on the load and carefully considering the ratings and material are crucial steps to ensure the safety and efficiency of the electrical system. When it comes to T&E cable quality, ZW Cable is your best choice, for we adopt the finest raw material, the strictest quality standard, and can customize cables. Most importantly, we offer superior products at the best price. ZW Welcome your inquiry.