UL 3958 Silicone Jacketed Power Cable Overview
UL AWM Style 3958 is a single-conductor cable construction using a non-integral extruded silicone rubber jacket, supplied by CableApex as a factory-direct manufacturer. The cable is rated 200°C and 600 Vac. Unlike a standard single-layer insulated wire, UL 3958 combines a qualified insulated conductor — labeled or complying with the manufacturer’s AWM procedures — with a separate outer silicone rubber jacket applied over it. UL defines the Style’s use simply as internal wiring; “power cable” is CableApex’s commercial positioning for this jacketed construction, not UL’s own terminology.
200°C / 600 Vac Single-Conductor Cable Construction
| Parameter | UL Style 3958 |
|---|---|
| UL Subject / Section | 758, Section 3 |
| Construction | Single-conductor cable using non-integral jacket |
| Rated Temperature (Maximum) | 200°C |
| Voltage Rating | 600 Vac |
| Flame Rating | Horizontal flame |
| Insulated Conductor | Labeled or complying with manufacturer’s AWM procedures |
| Conductor Size | According to the qualified insulated conductor / AWM procedure |
| Core Insulation | According to the qualified insulated conductor / AWM procedure |
| Covering | Optional |
| Shield | Optional |
| Jacket | Extruded silicone rubber (SR), 30 mil min. average / 24 mil min. at any point |
| Marking | General |
| Use | Internal wiring |
| RoHS / REACH | Confirmed during quotation according to ordered materials and documentation requirements |
Non-Integral Silicone Rubber Jacket
UL Style 3958’s defining feature is its non-integral jacket — a separate outer jacket layer applied around a qualified insulated conductor, rather than the conductor’s insulation itself serving as the outer surface. The confirmed jacket material is extruded silicone rubber (SR). This does not mean the underlying insulated conductor is also silicone-insulated; this page does not describe UL 3958 as a “silicone-insulated and silicone-jacketed” or “dual-layer silicone” cable, since the core insulation material is not established by the Style-level record.
30-Mil Minimum Average Jacket Requirement
The extruded SR jacket is specified at 30 mils minimum average thickness and 24 mils minimum thickness at any point. These values describe the jacket wall only — they do not define the underlying conductor’s insulation thickness, a total insulation-system thickness, or a finished cable outside diameter. We do not calculate or publish a finished OD from these jacket figures, as the underlying insulated conductor’s geometry is not universally established by the Style-level record.
Qualified Underlying AWM Insulated Conductor
The UL Style 3958 record defines the insulated conductor as labeled or complying with the manufacturer’s AWM procedures — it does not establish one universal AWG range, conductor material, conductor plating, conductor form (solid or stranded), or core insulation material for every Style 3958 cable. This page does not present a single “featured AWG” the way some of our other Power Cable product pages do, because no Style-wide conductor range is defined here. The underlying insulated conductor is selected from the qualified construction covered by the applicable AWM procedure and confirmed for your specific order.
Optional Covering and Shield Configurations
UL Style 3958 permits an optional covering and an optional shield, each independent of the required silicone rubber jacket. Neither is a standard component of every UL 3958 cable — we do not automatically describe the covering as fiberglass, aramid, mica tape, polyester, PVC, or PTFE, and we do not automatically describe the shield as foil, copper braid, tinned copper braid, or spiral shield, since none of these materials are established by the Style-level record. If your application requires a covering or shield, specify the requirement when requesting a quotation.
UL 3958 Technical Specifications
See the specification table above for the complete confirmed ratings and construction elements for this Style.
Equipment Internal Power Wiring Applications
UL Style 3958’s confirmed use is internal wiring. Appropriate commercial application language for this page includes equipment internal power connections, protected internal electrical connections, internal power routing within equipment, OEM equipment internal wiring, and jacketed internal wiring where Style 3958 is specified. This page does not extend the use to building wiring, branch circuit wiring, feeder cable, field wiring, tray cable, conduit cable, external flexible cord, portable power cord, extension cord, direct burial, or utility distribution — UL 3958 is not automatically an appliance supply cord, mains lead, AC power cord, or plug-ended external cable.
UL 3958 vs Standard Single-Layer Power Wire
UL 3958’s structural difference from a standard single-layer insulated wire is the added non-integral jacket. Our UL 3071 18 AWG Silicone Power Wire, by comparison, is a single-conductor insulated wire with extruded SR insulation applied directly to the conductor at 30 mil / 27 mil, referencing a Type SF-2 covering construction — a different structure from UL 3958’s separate jacket-over-qualified-conductor build, and the 30/24 mil figures on this page describe a jacket, not the same kind of primary insulation. UL 3958 is also distinct from UL 3582, which is a defined fluoropolymer-insulated, silicone-jacketed construction with its own voltage and temperature envelope, and from our Multi-Core Silicone Rubber Cable, which is explicitly a multiple-conductor product — UL 3958 remains a single-conductor cable throughout. Select based on the confirmed Style and structure your application actually requires.
What to Specify When Ordering UL 3958 Cable
Because UL Style 3958 relies on the manufacturer’s AWM procedure for the underlying insulated conductor, please specify the following so the correct qualified construction can be confirmed:
- Required conductor size / AWG
- Conductor material or plating, if specified
- Required underlying insulated-wire construction or UL Style, if specified
- Operating temperature
- Operating voltage
- Shield requirement, if any
- Optional covering requirement, if any
- Required jacket colour
- Required finished OD or maximum OD, if dimensionally constrained
- Marking requirement
- Order quantity
- Packaging requirement
- UL documentation requirement, including RoHS / REACH if needed
- Equipment type
- Internal power connection application
- Shipping destination
If you already have a specific AWG, conductor, insulation material, or underlying AWM Style in mind, these details will be confirmed against the qualified manufacturing construction before quotation — not every combination is automatically available. Send this information and we respond with a quotation within 12 business hours. Production lead time depends on the confirmed construction and order quantity, and shipping options and applicable Incoterms are confirmed during quotation according to destination.
UL Marking and Documentation
Qualifying UL AWM Style 3958 constructions can be supplied through the relevant qualified manufacturing scope for this Style. Because the underlying insulated conductor and order configuration can vary within the qualified procedure, UL marking and documentation are confirmed according to the qualified Style 3958 construction supplied for the order rather than presented as identical across every commercial variation. RoHS and REACH are separate regulatory frameworks from UL recognition; applicable RoHS / REACH documentation requirements can be confirmed according to the ordered construction.
Browse our full Power Cables category, or see our general AWM Wire family for related single-conductor constructions.
