What is SRML High Temp Wire?

The Extreme-Heat Motor Lead Wire

For industrial environments where heat and temperature extremes are unavoidable—such as motors in steel mills, foundries, ovens, kilns, or drying equipment—standard PVC or THHN lead wire will quickly fail.

An excellent option to consider is SRML Wire (Silicone Rubber Motor Lead).

SRML is a specialized single-conductor wire engineered with materials that resist temperatures that would melt or brittle-crack conventional insulation. It is a great choice for reliable internal and external wiring on high-heat industrial equipment, ensuring your motor and control circuits remain operational when the heat is on.

Below is some information that might help you with selecting this high-performance wire.

1. The Heat Advantage: Surviving the Extremes

SRML is defined by its ability to maintain electrical and mechanical integrity across a massive temperature range.

• High Temperature Rating: Standard SRML is rated for continuous operation up to 150ºC to 200ºC. This capacity is crucial for motors operating near high-temperature processes or in tight, unventilated spaces.

• Low Temperature Flexibility: Unlike standard elastomers that become brittle and crack in cold temperatures, the silicone rubber insulation remains highly flexible and resists cracking, typically down to -40ºC. This is vital for wiring that may be exposed to freezing conditions or rapid thermal cycling.

• Fire Resistance: When exposed to flame, the silicone rubber insulation turns into a non-conductive silica ash, which can provide a degree of circuit integrity long enough for emergency shutdown procedures.

2. Construction: Built for Mechanical Protection

SRML is built in layers, providing insulation, mechanical toughness, and abrasion resistance.

• Conductor Material: SRML uses finely stranded, tin-coated or bare Copper conductors. The stranding provides maximum flexibility, which is necessary for connections inside motor terminal boxes and high-vibration applications.

• Silicone Rubber Insulation: The inner layer is high-performance Silicone Rubber. This is the core component providing the high temperature rating and superior dielectric strength.

• The Outer Braid: The silicone layer is often protected by a heavy braided fiberglass or synthetic yarn serving. This braid provides essential abrasion and cut-through resistance during installation and in harsh operating environments.

3. Sizing, Rating, and Compliance

SRML wire is rated for voltage and application but requires careful consideration regarding termination.

• Voltage Rating: SRML is typically rated for 600 Volts, making it suitable for motor terminal leads, control panels, and power wiring up to the high-end industrial voltages.

• Ampacity: Because of its high temperature rating, SRML can often carry a higher current density than standard wire of the same size, but always consult the manufacturer's specific ampacity table.

• UL Listing: SRML wire meets various UL listings such as UL Style 3231, 3127, 3069, 3070 ensuring compliance with safety codes for high-temperature service.

• Installation Note: Since silicone rubber is soft, the outer fiberglass braid is vital. Care must be taken during stripping and termination to avoid damaging the underlying silicone insulation.

4. Primary Applications: Where SRML is Recommended

If heat is the primary failure threat, SRML is a great option:

• Motor Leads: Internal and external wiring for large industrial motors, especially in steel, glass, and paper mills.

• Foundries and Furnaces: Power and control wiring near heat-treating ovens and casting equipment.

• Control Panels: Wiring connections to resistance heaters, thermal sensors, and high-wattage components in enclosed panels.

• Appliance Wiring: Used in commercial cooking equipment, boilers, and industrial dryers.

5. Why Buy SRML High Temp Wire?

Choosing SRML means you are investing in a wire that will not only handle the heat but will also remain pliable and resistant to cracking for years. This drastically reduces the risk of thermal failure and costly operational downtime caused by brittle insulation.

Wire America is proud to offer this product by the foot or by the spool with fast shipping to your location. 

Click Here to Shop Our SRML High Temp Wire Selection

At Wire America, we believe in genuine conversation. You'll always talk with real people who understand that every project requires careful product selection. We're here to ensure you feel educated, confident, and great about your final purchase. Feel free to give us a call to discuss your project! You can reach us at: 833-268-8644

⚠️ Important Disclaimer: Safety and Compliance

Wire America provides this information as a guide only. Electrical installations must strictly adhere to the National Electrical Code (NEC) and all state, local, and jurisdictional requirements, which vary widely. Always consult a licensed electrician, electrical engineer, or the local inspecting authority before purchasing material or starting any electrical project. Wire America assumes no liability for the installation, use, or interpretation of these guides.