UL 3135 20 AWG — Selected Conductor Size Within the Style Range
This page covers UL AWM Style 3135 silicone rubber wire supplied at 20 AWG. The full Style range is 26 AWG through 12 AWG, placing 20 AWG in the fine-to-mid portion of that range. UL Style 3135 is rated 200°C at 600 Vac with extruded silicone rubber insulation at 30 mils minimum average and 27 mils minimum at any point, and the stated use is internal wiring of appliances where totally enclosed.
The insulation wall is uniform at 30 mils minimum average across the entire Style range, so at 20 AWG the finished outer diameter follows from the conductor construction alone. Where the equipment design calls for a flexible insulated conductor at this size within a totally enclosed appliance assembly, this construction is the relevant option. For other conductor sizes, see UL 3135 Silicone Wire.
UL AWM Style 3135 — Specifications
| UL AWM Style | 3135 |
| UL Subject / Section | 758, Section 3 |
| Temperature rating | 200°C |
| Voltage rating | 600 Vac |
| Conductor range (Style scope) | 26 AWG – 12 AWG, solid or stranded |
| Conductor size (this page) | 20 AWG |
| Insulation | Extruded silicone rubber (SR) |
| Minimum average insulation thickness | 30 mils (0.76 mm) |
| Minimum insulation at any point | 27 mils (0.69 mm) |
| Flame rating | Horizontal flame; VW-1 vertical flame test available |
| Marking | Per UL Subject 758 marking requirements; confirmed for the qualified ordered construction |
| Use per UL Style file | Internal wiring of appliances where totally enclosed |
| RoHS / REACH | Requirements confirmed according to ordered materials and documentation requirements |
Specifying 20 AWG
20 AWG is selected when the equipment design calls for this conductor size at the lead position in question. Available routing space, termination hardware, current requirements and the overall equipment design determine whether it is appropriate — the conductor size on its own does not establish suitability, and current-carrying requirements should be confirmed against the applicable engineering data for the equipment.
Where 20 AWG is confirmed, the remaining construction is settled at order stage. The UL Style file defines the insulation and the conductor size range but not the conductor material, finish or strand construction:
- Solid or stranded. Both are within the UL Style 3135 scope. Selected 20 AWG constructions can be supplied with stranded bare or tinned copper according to the confirmed order.
- Conductor finish. Bare or tinned copper is confirmed during quotation, normally driven by the termination process used in the assembly.
- Strand construction. Where your assembly requires a specific strand configuration, specify it at enquiry so it can be checked against production capability.
- Colour. Standard silicone colours are available; where multiple lead positions require identification, send a colour list with quantity per colour.
Handling and Routing Characteristics
Silicone rubber is a flexible insulation material, and stranded constructions may be selected where installation flexibility is important during appliance assembly. In practice this supports routing during the assembly step and handling of the lead into position within the appliance housing.
This is a material and handling characteristic rather than a dynamic-flex rating. UL Style 3135 is designated for internal wiring of appliances where totally enclosed — it is not classified for repeated bending, continuous movement or dynamic applications, and no flex-life or bending-radius data is published for these constructions. Where the equipment design involves movement of the wire in normal service, confirm the requirement separately rather than inferring it from the material.
Note also that silicone behaves differently from PVC under processing tooling. It is softer and compresses more readily, which affects stripper blade clearance and crimp settings — confirm the insulation dimensions at enquiry so tooling can be set against the actual ordered construction.
Totally Enclosed Appliance Internal Wiring
The UL Style 3135 file states the use as internal wiring of appliances where totally enclosed. This condition applies to the finished installation and is the boundary within which this product is supplied:
- Protected internal appliance leads routed entirely within the appliance housing
- Compact internal routing inside appliance housings where the available channel space suits a 20 AWG construction
- Protected internal appliance wiring in elevated-temperature areas, away from direct flame and direct heating-element contact
- OEM appliance wiring assemblies where 20 AWG silicone is a repeated lead specification
- Harness production where the finished assembly is installed as totally enclosed appliance internal wiring
Suitability for a specific appliance design depends on the equipment, the routing arrangement, the ordered construction and the applicable equipment-level evaluation. UL Style 3135 is not supplied or positioned as control panel wiring, general industrial internal wiring, field wiring, building wire, external wiring or heating-element connection wire.
Processing Notes
Where 20 AWG silicone wire is processed as part of an assembly operation, settle the following at enquiry:
- Cutting. Fixed-length cutting can be arranged where the assembly uses repeated lead lengths. Specify the required tolerance.
- Stripping. Confirm the insulation dimensions so stripper settings can be calibrated to the ordered construction.
- Termination. Confirm the terminal hardware so the conductor construction can be checked against the crimp barrel range, or specify a tinned finish where soldering is used.
- Reel and spool format. Confirm the format and length your assembly line works with.
UL Marking and Order Documentation
CableApex supplies UL AWM Style 3135 construction from factory production. UL marking and Style-specific documentation depend on the qualified ordered construction, and both should be confirmed during quotation. Where RoHS, REACH or other documentation is required, specify the requirement at enquiry so availability can be confirmed for the ordered materials and construction.
Buyer Specification Checklist
Send the following so a quotation can be prepared against a defined construction:
- 20 AWG confirmation
- Conductor construction — solid or stranded
- Bare or tinned conductor requirement
- Insulation colour, with quantity per colour
- Total quantity
- Reel or spool length
- Cut length and tolerance, if applicable
- Stripping requirement
- Termination process used in the assembly
- Marking requirement
- Documentation requirement
- Destination
Related UL AWM Styles
Buyers specifying UL 3135 20 AWG may also consider: UL 3135 Silicone Wire for the full 26–12 AWG Style range and other conductor sizes; and UL 3172 (200°C / 600 Vac, extruded silicone rubber with glass or aramid braid covering, 26–18 AWG — same temperature and voltage class with a braid covering, where the routing arrangement calls for one). The wider ranges are available under Silicone Rubber Wire and AWM Wire.
