UL 5128 Multi-Core Mica Glass Braid Cable — 450°C 300V
UL AWM Style 5128 is a single or multiple conductor with other-than-extruded insulation, rated 450°C and 300 Vac with a Horizontal flame classification. Each conductor is 24 AWG to 4 AWG, solid or stranded, insulated with non-extruded mica tape or a mica composite and covered by a glass braid treated with silicone varnish or TFE finish. The Style permits two or more of these conductors to be cabled together into one assembly, with a maximum assembly O.D. of 1.500 inches.
This page covers that multiple-conductor construction: what the Style permits for the assembly, which elements are optional, what each individual conductor must meet, and what an RFQ has to state for the assembly to be confirmed. For the broader Style overview, see the UL 5128 Mica Wire category.
Verified UL 5128 Multi-Conductor Specifications
| Parameter | UL AWM Style 5128 record |
|---|---|
| Style | 5128 |
| Description | Single or Multiple conductor with other-than-extruded insulation |
| Rating | 450°C, 300 Vac, Horizontal flame |
| Conductor range | 24 AWG – 4 AWG, solid or stranded |
| Insulation | Non-extruded Mica tape, or Mica composite (see facing page) |
| Per-conductor thickness, 24–12 AWG | Total mica tape layers 15 mils min avg; treated glass braid 7 mils min avg |
| Per-conductor thickness, 11–4 AWG | Total mica tape layers 20 mils min avg; treated glass braid 15 mils min avg |
| Braid treatment | Silicone Varnish or TFE Finish |
| Assembly (optional) | Two or more conductors described above may be cabled together |
| Maximum assembly O.D. | 1.500 inches (38.1 mm by unit conversion) |
| Assembly materials (optional) | Mica glass binder and/or fiberglass fillers may be employed |
| Overall covering (optional) | The assembly may have an overall treated glass braid |
| Shield (optional) | Stainless steel, alloy 304, applied as a braid over the treated glass braid |
| Marking | General |
| Use | Internal Wiring of high-temperature equipment where not subjected to repeated flexing and protected from mechanical abuse. (The acceptability, including current-carrying capacity, has been determined by Underwriters Laboratories Inc.) |
Four points in this table need clarification. First, 1.500 inches is a maximum for the assembly, not a standard or typical finished diameter. Second, the binder, fillers, overall treated glass braid and SS304 braid are each optional and independent; none is a default part of every assembly. Third, all mica and glass-braid values are minimum averages for the individual conductors; the record states no minimum-at-any-point value. Fourth, the record does not state a conductor material or plating; these are confirmed according to the qualified ordered construction.
Two or More Qualified Conductors in One Assembly
The assembly entry of Style 5128 reads: “Optional, two or more conductors described above, may be cabled together with a max O.D. of 1.500 inches.” Three points follow from that wording.
- The assembly is optional. Style 5128 is also supplied as single conductor; the multiple-conductor form is a permitted construction, not the only one.
- “Conductors described above” means fully qualified conductors. Each conductor in the assembly is a complete Style 5128 conductor, with its own mica insulation and treated glass braid meeting the Style’s thickness schedule.
- “Two or more” sets a minimum, not a list of configurations. The Style does not define any particular core count. The number of conductors for an order is set by the purchaser’s requirement and confirmed for the ordered construction.
Because no core counts are defined, this page does not offer standard configurations or estimate how many conductors of a given size fit within the maximum O.D. Whether a requested count, conductor size and set of options can be built within the 1.500-inch limit is confirmed against the ordered construction.
1.500-Inch Maximum Assembly OD
The Style limits the cabled assembly to a maximum O.D. of 1.500 inches (38.1 mm, given here as the metric conversion of the UL value). This is an upper limit for the assembly, not a target, standard or typical diameter, and not the finished diameter of every assembly.
The actual finished assembly diameter depends on the ordered configuration: the number and size of conductors, the actual dimensions of each insulated conductor, whether an SS304 braid is applied to the conductors, and whether binder, fillers and an overall braid are used. It is not estimated from AWG size and insulation thickness. Where a drawing controls the finished assembly diameter, that requirement is stated in the RFQ and confirmed, and in every case the assembly must remain within the 1.500-inch maximum.
Optional Mica Glass Binder and Fiberglass Fillers
The Style states: “A Mica glass binder and/or fiberglass fillers may be employed.” Both are optional assembly features. Either may be used alone, both may be used together, or neither may be used.
The record names these materials and does not assign them a function. It does not state that the binder holds conductors in position, prevents abrasion, improves vibration resistance or improves dielectric or thermal behaviour, and it does not state that fillers add mechanical strength, prevent conductor movement, improve roundness or affect flame or thermal rating. None of those properties is claimed here. Whether a binder, fillers or both are required is a construction choice for the RFQ.
Optional Overall Treated Glass Braid
The Style states: “The assembly may have an overall treated glass braid.” This is an optional covering over the complete assembly. It is described in the record as a treated glass braid; it is not described as a jacket, and it is not called one here.
The record does not attribute abrasion, mechanical, chemical or moisture protection or any flexibility effect to the overall braid. An assembly with an overall braid remains subject to the full Use, including protection from mechanical abuse. Whether the overall braid is required, and any treatment requirement for it, is stated in the RFQ.
Individual Conductor Mica and Glass-Braid Requirements
Each conductor in the assembly must meet the single-conductor requirements of Style 5128 for its size group:
| Conductor size group | Total mica tape layers, min average | Treated glass braid, min average |
|---|---|---|
| 24 – 12 AWG | 15 mils | 7 mils |
| 11 – 4 AWG | 20 mils | 15 mils |
Three points in this table need clarification. First, “total mica tape layers” means the combined thickness of all mica tape layers on a conductor. Second, both values are minimum averages; they are not nominal, exact or point minimums, and the finished diameter of an individual conductor is not derived from them. Third, the glass braid on each conductor is treated with silicone varnish or TFE finish; these are braid finishes, not primary insulation.
The conductors themselves are solid or stranded within 24–4 AWG. The record does not define conductor material, plating, strand count, strand diameter, lay length, conductor class or resistance, and these are confirmed according to the qualified ordered construction.
Optional Stainless Steel Alloy 304 Braid
The Style also permits an optional braid of stainless steel, alloy 304, applied over the treated glass braid. In a multiple-conductor order, where and how this option is applied should be stated in the RFQ and confirmed for the ordered construction. The record establishes the presence, material and position of this optional braid only; it does not establish shielding effectiveness, noise reduction, measurement accuracy, abrasion, crush or thermal protection. The option is covered in detail on the UL 5128 mica wire with optional SS304 braid page.
Internal Wiring, Repeated-Flexing and Mechanical-Protection Limits
The Use reads: “Internal Wiring of high-temperature equipment where not subjected to repeated flexing and protected from mechanical abuse. (The acceptability, including current-carrying capacity, has been determined by Underwriters Laboratories Inc.)” For a multiple-conductor assembly this means:
- Protected multiple-conductor internal wiring in high-temperature equipment, where the exact conductor, circuit and assembly requirements are confirmed by the purchaser. The Style does not designate instrumentation, sensor, thermocouple, RTD or control-circuit use, and none is designated here.
- No repeated flexing: the assembly is not a continuous-flex, robotic or drag-chain cable, and no bend radius or flex life is given.
- Protected from mechanical abuse: field, building, tray, outdoor and direct-burial use fall outside the Use, and neither the overall treated glass braid nor the SS304 braid removes this requirement.
- Current-carrying capacity: it sits within UL’s determination of acceptability. No ampacity is published or derived from AWG.
What Style 5128 Does and Does Not Define for Multi-Core Assemblies
The Style record defines the rating; the conductor range and form; the insulation and per-conductor thickness schedule; the braid treatments; the optional assembly of two or more conductors with a maximum O.D. of 1.500 inches; the optional mica glass binder, fiberglass fillers, overall treated glass braid and SS304 braid; the marking field (General); and the Use.
The Style record does not define:
- any specific core count or standard configuration
- how many conductors fit within 1.500 inches
- a standard finished assembly diameter
- any function or performance of the binder, fillers or overall braid
- conductor material, plating or strand construction
- conductor resistance or current rating
- conductor identification, colour coding or lay-up arrangement
- bend radius, flex life or service life
Common Procurement Errors
- Treating 1.500 inches as the standard finished diameter.
- Requesting a core count without confirming it fits within the maximum O.D.
- Assuming binder, fillers or overall braid are included by default.
- Calling the overall treated glass braid a jacket or attributing protection to it.
- Specifying conductors that do not individually meet the Style thickness schedule.
- Assuming a conductor material or plating.
- Assigning current ratings from AWG.
- Specifying the assembly for repeated flexing or unprotected routing.
UL 5128 Multi-Core RFQ Information
The Style fixes the rating, conductor range, insulation and per-conductor thickness schedule, braid treatments, the assembly options with the 1.500-inch maximum O.D., and the Use. The following should be stated by the buyer and confirmed for the ordered qualified construction, not filled with assumed values:
- AWG
- solid or stranded requirement
- conductor material and finish requirement
- detailed stranding, if controlled
- number of conductors
- mica tape or applicable qualified mica composite
- glass-braid treatment requirement
- optional SS304 braid requirement
- mica glass binder requirement
- fiberglass filler requirement
- overall treated glass braid requirement
- finished assembly OD requirement, if controlled
- marking requirement
- quantity
- packaging
- documentation requirements
- equipment type
- internal routing position
- mechanical-protection conditions
- confirmation that repeated flexing is not involved
UL Marking and Documentation
Style 5128 wire is supplied as UL-recognized component wire where supplied under qualified manufacturing scope. The marking field of the Style record reads “General”; it does not prescribe a fixed legend, and identical marking is not assumed for every possible assembly configuration. UL marking is applied according to the confirmed ordered construction and should be confirmed at the order stage.
Applicable RoHS / REACH documentation can be confirmed according to the ordered construction. CE, UKCA, CSA, FT1, VW-1, CPR, VDE, DIN, EN and IEC are not declared for this product.
Commercial, origin, compliance and transport documents are identified during quotation and confirmed according to the order.
