Silicone wire is widely used in electrical and electronic equipment where high temperature resistance, flexibility, electrical insulation and long-term reliability are required.

Compared with conventional PVC-insulated wires, silicone rubber insulated wire provides excellent flexibility and thermal stability while maintaining reliable electrical insulation. It is particularly suitable for internal wiring, heating equipment, electronic devices, industrial machinery, electric vehicles and other applications exposed to heat, vibration or limited installation space.

Winpower offers a range of UL silicone wire solutions, including UL3132, UL3133, UL3135, UL3239, UL3512, UL3572, UL3787, UL3858, UL30056 and UL4330.

These UL silicone wires cover different voltage and temperature requirements, from 300V general-purpose internal wiring to 3000V high-voltage applications, as well as multi-core and flexible wiring solutions.

This guide compares the key characteristics, specifications and applications of these UL silicone wire types to help engineers, OEM manufacturers and cable buyers select the appropriate solution.

1. What Is UL Silicone Wire?

UL silicone wire is an electrical wire that uses silicone rubber as its insulation material and is manufactured according to applicable UL requirements.

Silicone rubber is well suited to demanding electrical environments because it combines:

• High-temperature resistance
• Low-temperature flexibility
• Excellent flexibility
• Reliable electrical insulation
• Aging resistance
• Chemical resistance
• Good moisture resistance
• Easy installation
• Long service life

The supplied reference material describes silicone high-temperature wire as having good resistance to high and low temperatures, high voltage, aging, acids and alkalis. It also emphasizes its soft and flexible construction, which makes installation easier.

Today, silicone insulated wire is used across a wide range of industries, including household appliances, lighting, industrial equipment, EVs, robotics, medical equipment, electronic instruments and high-temperature machinery.

2. Why Choose Silicone Rubber Insulation?

2.1 High Temperature Resistance

One of the main advantages of silicone wire is its ability to operate in elevated-temperature environments.

Different UL silicone wire styles provide different temperature ratings. For example:

• UL3132: up to 150°C
• UL3133: up to 150°C
• UL3135: up to 200°C
• UL3512: up to 200°C
• UL3572: up to 200°C
• UL3787: 150°C
• UL3858: 150°C
• UL30056: up to 200°C
• UL4330: up to 150°C

The exact temperature rating depends on the specific UL style and construction.

2.2 Excellent Flexibility

Silicone rubber remains soft and flexible, making silicone wire easier to route through compact electrical assemblies.

This is particularly valuable for:

• Robotic arms
• EV electrical systems
• Compact electronic equipment
• Appliance internal wiring
• Industrial machinery
• Moving assemblies
• Precision instruments

UL3133, for example, is described as a flexible high-temperature wire using fine-stranded tinned copper and silicone rubber insulation.

2.3 High Voltage Insulation

Silicone wire is not limited to low-voltage internal wiring.

The UL silicone wire family also includes high-voltage products such as UL3239, UL3858 and UL30056.

The supplied UL3239 information covers voltage options from 3KV to 50KV, while the referenced UL3858 and UL30056 products are designed for 3000V applications.

2.4 Good Low-Temperature Performance

Silicone insulation can maintain flexibility in low-temperature environments.

For example, the referenced UL3133 and UL3572 specifications list minimum operating temperatures of -40°C.

This makes silicone wire suitable for applications where the cable may experience both temperature extremes.

2.5 Chemical and Environmental Resistance

Silicone insulated wire can provide good resistance to aging, moisture, ozone and various environmental conditions.

The supplied reference material also identifies resistance to acids and alkalis.

For applications exposed to oil, chemicals or other demanding environments, the complete cable construction should be selected according to the actual application requirements.

3. UL Silicone Wire Product Range

The following products represent the UL silicone wire series covered in this guide:

*UL3133: the referenced 3A page contains conflicting voltage information; Nizing lists 600V AC / 150°C, while the 3A technical specification section lists 300V. Verify against the final product specification before publication.

*UL3239 temperature and voltage options vary by construction; the supplied reference document lists 3KV–50KV and -60°C to +150/+200°C.

4. UL3132 Silicone Wire

UL3132 is a flexible silicone rubber insulated wire designed for internal electrical connections.

According to the supplied product information, UL3132 has a rated voltage of 300V, a temperature range of -60°C to +150°C, and a test voltage of 1500V.

UL3132 Specifications

UL3132 is suitable for internal fixed connections in lighting equipment, household appliances and electronic/mechanical equipment.

Its 300V rating and flexible silicone insulation make it suitable for general internal wiring applications where higher temperature performance is required.

5. UL3133 Flexible Silicone Wire

UL3133 is a flexible high-temperature silicone wire designed for electrical and electronic equipment.

The referenced Nizing specification lists:

• Rated voltage: 600V AC
• Maximum temperature: 150°C
• Minimum temperature: -40°C
• Maximum test voltage: 6000V
• Silicone insulation

The 3A product page describes UL3133 as a flexible wire using a fine-stranded tinned copper conductor and silicone rubber insulation, with applications in EV control systems, robotics, industrial wiring, laboratory equipment and thermal applications.

Key Advantages

• Flexible fine-stranded conductor
• Silicone rubber insulation
• High-temperature performance
• Good routing flexibility
• Suitable for compact wiring
• Designed for demanding electrical environments

Typical Applications

UL3133 can be used for:

• EV control systems
• BMS and signal wiring
• Robotics
• Automation equipment
• Industrial heating equipment
• Thermal sensors
• Laboratory instruments
• Precision electronics

For applications requiring both flexibility and elevated-temperature performance, UL3133 can be an attractive option.

6. UL3135 Silicone Wire

UL3135 is a 600V high-temperature silicone wire designed for internal connections in electrical and electronic equipment.

The supplied product information specifies:

• Rated voltage: 600V
• Temperature range: -60°C to +200°C
• Test voltage: 2000V
• Silicone rubber insulation
• Tinned, nickel-plated, silver-plated or gold-plated copper conductor

Typical Applications

UL3135 is suitable for internal fixed wiring in:

• Lighting equipment
• Household appliances
• Electronic equipment
• Electromechanical equipment

Compared with UL3132, UL3135 provides a higher rated voltage and higher temperature rating, making it suitable for equipment requiring up to 600V and 200°C performance.

7. UL3239 High-Voltage Silicone Wire

UL3239 is designed for high-voltage applications where conventional low-voltage silicone wire is not sufficient.

The supplied product information lists voltage options including:

3KV / 6KV / 10KV / 20KV / 30KV / 40KV / 50KV

It also lists a temperature range of -60°C to +150/+200°C, with tinned copper or nickel-plated copper conductors and silicone rubber insulation.

Key Features

• High-voltage insulation
• Silicone rubber insulation
• Multiple voltage options
• Flexible construction
• Tinned or nickel-plated copper conductor
• Suitable for high-voltage electronic equipment

Applications

The supplied material identifies applications including:

• LCD televisions
• Microwave ovens
• Fax machines
• Printers
• Copiers
• Scanners
• Cold cathode tube high-voltage wiring

UL3239 is therefore particularly suitable for applications requiring high-voltage insulation combined with silicone flexibility.

8. UL3512 Silicone Wire

UL3512 is a 600V high-temperature silicone rubber wire designed primarily for appliance and internal wiring applications.

The referenced Siechem specification lists:

• Rated voltage: 600V AC
• Temperature range: -60°C to +200°C
• Conductor: annealed tinned solid/stranded copper
• Insulation: silicone rubber
• Standard: UL 3512
• Test method: UL 758

Key Features

The referenced product information highlights:

• Low-temperature resistance
• Flame retardancy
• Halogen-free construction
• Oil resistance
• Ozone resistance
• Resistance to chemical oil and fuel

Typical Applications

UL3512 is listed for:

• Appliance wiring
• Internal wiring of electric clothes dryers

This makes UL3512 particularly relevant to appliances where high temperature, oil resistance and reliable internal wiring are required.

9. UL3572 Silicone Wire

UL3572 is a high-temperature silicone wire designed for applications requiring higher voltage and temperature performance.

The referenced Nizing specification lists:

• Rated voltage: 1000V AC
• Maximum temperature: 200°C
• Minimum temperature: -40°C
• Maximum test voltage: 10000V

One notable feature of UL3572 is its conductor construction. According to the referenced product information:

• Conductors below 0.38 mm diameter use nickel-plated copper
• Conductors of 0.38 mm diameter and above use tinned copper

Applications

UL3572 is positioned for wiring in high-temperature or precision environments, including:

• Household appliances
• Lighting equipment
• Industrial machinery
• Electric heating products
• Raw material furnaces
• Robotic arms
• AI data centers
• Electric vehicles
• Medical equipment
• Precision electronic instruments
• 5G equipment
• High-speed communication equipment

The combination of 1000V rating, 200°C temperature capability and flexible silicone insulation makes UL3572 particularly interesting for modern industrial and high-temperature electrical systems.

10. UL3787 Silicone Rubber Hook-Up Wire

UL3787 is a silicone rubber hook-up wire designed for applications requiring a combination of higher voltage and high-temperature performance.

The referenced Winpower product listing identifies UL3787 as:

150°C / 1000V AC Silicone Rubber Hook-Up Wire.

Key Characteristics

• Rated voltage: 1000V AC
• Temperature rating: 150°C
• Silicone rubber insulation
• Hook-up wire construction
• Suitable for high-temperature electrical wiring

UL3787 is positioned between conventional 600V silicone hook-up wires and higher-voltage silicone wire products.

It can therefore be considered for electrical equipment requiring a 1000V rating with 150°C temperature performance, subject to the specific product construction and application requirements.

11. UL3858 High-Voltage Silicone Rubber Cable

UL3858 is a high-voltage silicone rubber cable designed for demanding electrical and automotive applications.

The referenced Linke product identifies:

• Rated voltage: 3000V AC
• Rated temperature: 150°C
• Conductor: tinned copper
• Insulation/sheath: silicone rubber
• Multiple-core options
• Flexible construction

The product is specifically positioned for electric vehicles and high-voltage applications.

Typical Applications

UL3858 can be used in:

• EV high-voltage boxes
• Motor control units
• Charging sockets
• Battery management systems
• Electric buses
• High-power electrical systems

The referenced product also provides both shielded and non-shielded constructions, giving designers more flexibility when electromagnetic shielding is required.

12. UL30056 High-Voltage Silicone Rubber Wire

UL30056 is a high-voltage silicone rubber wire designed for high-potential electrical circuits and demanding thermal environments.

The Winpower product specification identifies:

• Rated voltage: 3000V AC
• Rated temperature: 200°C
• Silicone rubber insulation
• FT2 horizontal flame test
• UL Subject 758 / UL1581
• RoHS compliance

Key Features

3000V High-Voltage Performance

UL30056 is designed for high-potential circuits where reliable dielectric insulation is required.

200°C Temperature Resistance

The silicone rubber insulation is designed to remain flexible and electrically stable at temperatures up to 200°C according to the referenced product specification.

Wide Conductor Size Range

The referenced Winpower product lists sizes from 22 AWG to 350 kcmil, covering applications ranging from signal/control wiring to larger power connections.

Oil Resistance

The product is also positioned for appliance internal wiring where exposure to oil may occur.

UL30056 is therefore suitable for applications requiring a combination of 3000V high-voltage insulation and 200°C high-temperature performance.

13. UL4330 Multi-Core Silicone Wire

UL4330 is different from many of the single-core silicone wires in this series because it uses a multi-core construction.

According to the Winpower product specification:

• Rated voltage: 300V AC
• Temperature range: -40°C to +150°C
• Test voltage: 2000V
• Insulation: eco-friendly silicone rubber
• Construction: multi-core
• Diameter tolerance: 0.2–0.5mm

Key Features

Multi-Core Construction

The multi-core structure allows multiple electrical circuits or signals to be integrated into one cable assembly.

High Flexibility

The silicone rubber insulation provides flexibility for compact or moving applications. The product is specifically positioned for robotic arms and compact electronic housings.

High-Temperature Performance

The -40°C to +150°C operating range makes UL4330 suitable for equipment exposed to temperature fluctuations.

Applications

UL4330 is positioned for:

• AI data centers
• 5G base stations
• High-speed communication equipment
• Electric vehicles
• Charging infrastructure
• Robotic arms
• Industrial machinery
• Medical equipment
• Precision instruments
• Household appliances
• Lighting equipment

For applications requiring multiple conductors, flexibility and high-temperature performance in a compact cable structure, UL4330 provides a different solution from single-core UL silicone wires.

14. UL Silicone Wire Comparison

The comparison shows that the UL silicone wire family can be broadly divided into four groups:

300V Class

• UL3132
• UL4330

600V Class

• UL3133
• UL3135
• UL3512

1000V Class

• UL3572
• UL3787

High-Voltage Class

• UL3239
• UL3858
• UL30056

This classification makes it easier for engineers and purchasing teams to identify suitable products according to voltage requirements.

15. How to Choose the Right UL Silicone Wire?

Selecting a UL silicone wire should not be based only on the UL number.

A practical selection process should consider the following five factors.

15.1 Rated Voltage

The first step is to identify the maximum operating voltage.

For example:

300V → UL3132 / UL4330

600V → UL3133 / UL3135 / UL3512

1000V → UL3572 / UL3787

3000V → UL3858 / UL30056

3KV–50KV → UL3239

The actual application, construction and certification requirements should always be checked before final selection.

15.2 Operating Temperature

Determine both the maximum and minimum working temperatures.

For high-temperature applications, products such as UL3135, UL3512, UL3572 and UL30056 provide temperature ratings up to 200°C according to the referenced product information.

15.3 Conductor Material

Different applications may require different conductor constructions.

Common options include:

• Bare copper
• Tinned copper
• Nickel-plated copper
• Silver-plated copper
• Gold-plated copper

For example, UL3572 uses nickel-plated copper for smaller conductor diameters and tinned copper for larger conductor diameters according to the referenced Nizing specification.

15.4 Single-Core or Multi-Core

Choose the construction according to the electrical architecture.

Single-Core Wire

Suitable for:

• Internal power connections
• Hook-up wiring
• High-voltage wiring
• Individual circuit connections

Multi-Core Wire

Suitable for:

• Combined power and signal wiring
• Control systems
• Robotics
• Compact equipment
• Complex electronic assemblies

UL4330 is an example of a multi-core silicone wire designed for high-flexibility applications.

15.5 Application Environment

The working environment should also be evaluated.

Consider:

• Heat
• Cold
• Oil
• Chemicals
• Moisture
• Vibration
• Mechanical movement
• Installation space
• Electrical stress

The correct silicone wire should be selected based on the complete application rather than voltage alone.

16. UL Silicone Wire Applications

The wide performance range of UL silicone wire makes it suitable for many industries.

Household Appliances

Applications include:

• Clothes dryers
• Heating appliances
• Kitchen appliances
• Household electronic equipment

UL3512, for example, is specifically listed for appliance wiring and internal wiring of electric clothes dryers.

EV and Automotive Electronics

Silicone wires can be used for:

• EV control systems
• BMS wiring
• High-voltage boxes
• Motor control units
• Charging systems
• Internal electronic connections

UL3133 is positioned for EV control and BMS-related wiring, while UL3858 is designed for high-voltage EV applications.

Robotics and Industrial Automation

Robotic systems require wires that can withstand heat, movement and repeated bending.

UL3133, UL3572 and UL4330 are particularly relevant to robotics and industrial automation applications according to the referenced product information.

AI Data Centers and Communication Equipment

Modern data centers and communication systems increasingly require compact, flexible and thermally stable wiring.

UL3572 and UL4330 are positioned for applications including AI data centers, 5G and high-speed communication equipment.

Medical and Precision Equipment

Silicone wire can also be used in:

• Medical equipment
• Laboratory instruments
• Precision electronic equipment
• Instrumentation systems

UL3133, UL3572 and UL4330 are referenced for medical, laboratory or precision electronic applications.

17. UL Silicone Wire vs. Conventional PVC Wire

The major difference between silicone and conventional PVC insulated wire is the balance between temperature performance and flexibility.

Silicone wire is particularly attractive when the application requires high temperature resistance plus flexibility.

However, silicone should not automatically be considered the best choice for every application. Voltage, mechanical protection, abrasion, chemical exposure, current capacity and installation requirements must all be evaluated.

18. Why Choose Winpower UL Silicone Wire?

For OEMs and equipment manufacturers, choosing a silicone wire supplier requires more than simply purchasing a standard UL style.

The supplier should be able to understand the relationship between:

Voltage + Temperature + Conductor + Insulation + Construction + Application

Winpower’s UL silicone wire portfolio covers:

• 300V silicone wire
• 600V silicone wire
• 1000V silicone wire
• 3000V high-voltage silicone wire
• Multi-core silicone wire
• High-temperature silicone wire
• Flexible silicone wire
• High-voltage silicone wire

This allows different wire constructions to be matched to different equipment requirements.

For example:

General internal wiring → UL3132

Flexible high-temperature wiring → UL3133

600V / 200°C applications → UL3135

High-voltage equipment → UL3239

Appliance wiring → UL3512

1000V / 200°C applications → UL3572

1000V / 150°C applications → UL3787

3000V EV applications → UL3858

3000V / 200°C applications → UL30056

Multi-core flexible wiring → UL4330

19. Frequently Asked Questions About UL Silicone Wire

What is UL silicone wire?

UL silicone wire is an electrical wire using silicone rubber as the insulation material and designed to meet the requirements of the applicable UL style.

Why is silicone used for high-temperature wire?

Silicone rubber provides good thermal stability while maintaining flexibility, making it suitable for electrical equipment exposed to elevated temperatures.

What is the difference between UL3132 and UL3135?

According to the supplied specifications, UL3132 is rated at 300V and -60°C to +150°C, while UL3135 is rated at 600V and -60°C to +200°C.

What is UL3133 used for?

UL3133 is a flexible silicone wire used for applications including EV control systems, robotics, industrial equipment, laboratory equipment and high-temperature wiring.

What is UL3239 used for?

UL3239 is a high-voltage silicone wire designed for applications requiring higher voltage insulation performance. The supplied reference lists voltage levels from 3KV to 50KV.

What is UL3572 rated for?

The referenced UL3572 specification lists a maximum voltage of 1000V AC, maximum temperature of 200°C, minimum temperature of -40°C and maximum test voltage of 10000V.

What is UL3858 used for?

UL3858 is a 3000V AC silicone rubber cable designed for high-voltage applications including EV high-voltage boxes, motor control units, charging sockets and battery management systems.

What is UL30056?

UL30056 is a 3000V AC high-voltage silicone rubber wire with a 200°C temperature rating according to the referenced Winpower product information.

What is UL4330?

UL4330 is a multi-core silicone wire rated at 300V AC and -40°C to +150°C, designed for applications such as robotics, EVs, AI data centers, 5G equipment and precision electronics.

Can silicone wire be customized?

Depending on the manufacturer and UL style, conductor material, conductor size, color, core configuration, length and other construction parameters may be customized. The final configuration must remain consistent with the applicable certification and product requirements.

20. Conclusion

UL silicone wire is an important solution for electrical applications requiring a combination of high-temperature resistance, flexibility, electrical insulation and long-term reliability.

The UL silicone wire family covers a wide range of applications and electrical requirements.

From 300V internal wiring to 1000V high-temperature applications and 3000V high-voltage systems, different UL styles provide different performance characteristics.

The product range covered in this guide includes:

UL3132 · UL3133 · UL3135 · UL3239 · UL3512 · UL3572 · UL3787 · UL3858 · UL30056 · UL4330

The right product should be selected according to:

Rated Voltage → Temperature → Conductor → Construction → Environment → Application

For OEM manufacturers, electrical engineers and cable distributors, understanding these parameters can help identify the most suitable silicone wire for each project.

Winpower provides UL silicone wire solutions for high-temperature, high-voltage, flexible, multi-core and demanding electrical applications.