UL 3135 Silicone Rubber Motor Lead Wire — 200°C / 600V, Class H Insulation System
UL Style 3135 silicone rubber wire is the standard UL AWM construction for motor lead wiring in Class H insulation system motors, generators, and transformers. Rated 200°C continuous and 600 Vac under UL Subject 758, Style 3135 provides the 20°C thermal margin above the IEC 60085 Class H maximum winding temperature of 180°C required for reliable long-term motor lead performance — with the flexibility characteristic of silicone rubber insulation that allows routing through the tight clearances inside motor end shields and terminal boxes.
For international buyers familiar with Chinese-designation JG and JE motor lead wire, UL Style 3135 is the UL-recognized equivalent construction — extruded silicone rubber insulation at 30 mils minimum average wall over solid (JG equivalent) or stranded (JE equivalent) copper conductor, manufactured under UL Follow-Up Service and carrying the UL Recognized Component Mark on the wire surface.
Technical Specifications — UL Style 3135 Motor Lead Wire
| Parameter | Specification |
|---|---|
| UL Style | 3135 |
| UL Subject | 758, Section 3 |
| Temperature Rating | 200°C continuous / –60°C lower limit |
| Voltage Rating | 600 Vac |
| AWG Range | 26 AWG – 12 AWG, solid or stranded |
| Insulation Material | Extruded silicone rubber (SR) |
| Insulation Thickness | 30 mils min average / 27 mils min at any point |
| Flame Rating | Horizontal flame |
| IEC Insulation Class | Class H (180°C) — wire rated 200°C for 20°C thermal margin |
| UL Recognition | UL Recognized Component — file on record |
| Color Options | Red, black, white, yellow, blue, green (custom on request) |
| MOQ | 100 meters / cut-to-length from 1 meter for MRO orders |
IEC Insulation Class Reference — Where UL 3135 Fits
| IEC 60085 Class | Max Temperature | Recommended UL AWM Wire |
|---|---|---|
| Class B | 130°C | UL 1015 PVC 105°C (derated in enclosure) |
| Class F | 155°C | UL 3321 XLPE 150°C / UL 3135 SR 200°C |
| Class H (this product) | 180°C | UL 3135 Silicone Rubber 200°C ← recommended |
| Class C | >180°C | UL 5107 Mica-fiberglass 450°C |
Motor Lead Application Categories
Class H Motor Winding Terminal Connections
The primary application is the motor lead — the short wire connecting the motor winding terminal to the terminal box screw connections. In a Class H insulation motor, this wire sits at the highest temperature point in the motor and must maintain insulation integrity throughout the motor’s service life. UL 3135 silicone rubber provides the 200°C rating with the flexibility to route through tight clearances inside motor end shields and terminal boxes without cracking or fatigue at tight bend radii.
Generator and Alternator Internal Wiring
Stator and exciter winding connection leads in generators and alternators where sustained operating temperature, vibration, and long service life in remote installations demand wire that will not harden, crack, or lose dielectric integrity over decades of operation. UL 3135’s –60°C to 200°C continuous rating covers the full thermal range from cold-start to full-load operating temperature in both standby and prime power generator applications.
Transformer Internal Lead Connections
Connection leads between transformer winding ends and the terminal board in dry-type transformers operating at Class H temperature, where the lead must survive the winding hot-spot temperature while remaining flexible enough to accommodate thermal expansion movement during load cycling.
MRO Motor Lead Replacement
Motor rewinding workshops and maintenance operations require Class H motor lead wire in small quantities — cut to specific lengths matched to the motor frame size. UL 3135 is available cut-to-length from 1 meter for MRO motor repair orders, with phase-colour-coded sets (red/yellow/blue) for three-phase motor lead replacement. Specifying UL-recognized wire for motor lead replacement ensures the repaired motor maintains its original compliance documentation chain for export market resale or warranty claims.
Other Motor Lead Applications
- Submersible pump motor lead wire replacement
- Servo motor and stepper motor terminal connections
- Industrial fan and blower motor internal wiring
- HVAC compressor motor lead replacement
Related UL Styles for Comparison
UL 3135 motor lead buyers commonly cross-reference: UL 3071 (200°C / 600V silicone rubber with fiberglass braid SF-2 covering, 18–13 AWG for motor leads requiring mechanical protection), UL 3321 (150°C / 600V XLPE, Class F motor lead alternative at lower temperature rating), UL 3271 (125°C / 600V XLPE, Class B/E motor lead wire for standard industrial motors), and UL 3172 (200°C / 600V silicone rubber with glass or aramid braid, 26–18 AWG for enhanced mechanical protection).
Request a Quote
Submit your AWG, conductor type (solid or stranded), color, spool length or cut-to-length requirement, and annual volume estimate below. Phase-colour-coded motor lead sets available. Our team responds within 24 business hours. Free 10-meter samples available upon request.
