UL 5334 24–12 AWG Mica Glass Wire — 17/5 Mil Construction
UL AWM Style 5334 is a single conductor with other-than-extruded insulation, rated 450°C and 300 Vac with a Horizontal flame classification. Its insulation and braid are described as “Non-extruded Mica with Glass Braid,” with thickness set by conductor-size group. For 24 AWG through 12 AWG, the Style requires a minimum average wall of 17 mils of Composite Mica Glass and a minimum average thickness of 5 mils of treated Glass Braid.
This page covers that 24–12 AWG construction: the meaning of the two minimum-average requirements, the braid treatment wording, the conductor forms, and the conditions in the Style’s Use. The heavier 11–4 AWG group, with its 20/10 mil requirements, is covered on the separate UL 5334 11–4 AWG mica glass wire page. For the broader Style overview, see the UL 5334 Mica Wire category.
Verified UL 5334 24–12 AWG Specifications
| Parameter | UL AWM Style 5334 record, applied to 24–12 AWG |
|---|---|
| Style | 5334 |
| Description | Single conductor with other-than-extruded insulation |
| Conductor group | 24 AWG – 12 AWG (within the 24 AWG – 4 AWG Style range) |
| Conductor form | Solid or stranded |
| Temperature | 450°C |
| Voltage | 300 Vac |
| Flame | Horizontal flame |
| Insulation and braid | Non-extruded Mica with Glass Braid |
| Composite Mica Glass | 17 mils (0.43 mm) minimum average wall |
| Treated Glass Braid | 5 mils (0.13 mm) minimum average thickness |
| Braid treatment | Silicone Varnish or TFE Finish |
| Optional shield | Stainless steel, alloy 304, applied as a braid over the treated glass braid |
| Marking | General |
| Use | Wiring of ovens or similar high-temperature equipment where protected from mechanical abuse and where the acceptability, including current-carrying capacity, has been determined by Underwriters Laboratories Inc. |
Four points in this table need clarification. First, the millimetre values are arithmetic conversions (1 mil = 0.0254 mm), not separate UL specifications. Second, both thickness values are minimum averages; the record states no minimum-at-any-point value. Third, Style 5334 is a single-conductor Style; its record lists no multiple-conductor assembly. Fourth, the record does not state a conductor material or plating; these are confirmed according to the qualified ordered construction.
17 Mil Minimum-Average Composite Mica Glass
The Style’s thickness table is headed “Min Avg wall of Composite Mica Glass.” For 24–12 AWG the value is 17 mils (0.43 mm by unit conversion). The average wall of the composite mica glass layer must not fall below 17 mils.
The 17-mil figure is a minimum average. It is not nominal, exact or typical, and it is not a minimum at any point. The actual wall of an ordered construction may exceed it, and no tolerance is attached to it. The record does not describe it as a thin, compact or reduced wall, and this page does not compare it with other Styles as a compact or minimum-diameter construction.
The record names the material “Composite Mica Glass” within an insulation described as “Non-extruded Mica with Glass Braid.” It does not describe the composite’s makeup, mica type or manufacturing process, and none is described here. The record also makes no comparison between composite mica glass and mica tape. No resistance to shifting, slipping, delamination or cracking, and no thermal-cycling, uniformity, adhesion or stability advantage is attributed to it.
5 Mil Minimum-Average Treated Glass Braid
Over the composite mica glass is a glass braid. For 24–12 AWG, the Style requires a minimum average braid thickness of 5 mils (0.13 mm by unit conversion). This is a minimum average only; it is not nominal or exact, and no point minimum is stated.
The two values describe two separate layers. They are not added together here as a finished wall; 17 plus 5 mils is not a Style value and not a universal wall figure. Neither the finished outside diameter nor the conductor diameter is derived from them, because conductor construction and other qualified construction details also determine finished dimensions. Where a drawing controls finished diameter or its tolerance, that requirement is stated in the RFQ and confirmed for the ordered construction.
Silicone Varnish or TFE Finish
The braid column of the Style table is headed “Glass Braid Treated with Silicone Varnish or TFE Finish.” Both treatments are permitted. The Style does not tie either one to a temperature or an application, and it does not rank them. They are finishes on the glass braid, not primary insulation: silicone varnish is not silicone rubber insulation, and TFE finish is not PTFE insulation. The record makes no statement about their relative flexibility, abrasion, chemical or dielectric behaviour, or life. Where a drawing requires one treatment, it is confirmed for the ordered construction.
Solid or Stranded Construction from 24 to 12 AWG
The conductor field reads “24 AWG – 4 AWG, solid or stranded.” Both forms are permitted across the whole Style range, so every size from 24 AWG to 12 AWG may be solid or stranded. The Style does not attribute any flexibility or installation advantage to either form.
The record does not define conductor material, plating, strand count, strand diameter, conductor class, lay length or stranding method. No particular conductor material or plating is required or recommended by the Style on the basis of its 450°C rating. Conductor resistance and current rating are not given. These details are confirmed according to the qualified ordered construction.
“Single conductor” in the Style description refers to the construction as a whole. A stranded conductor remains one conductor, and the Style does not provide for cabling several insulated conductors together.
450°C / 300 Vac / Horizontal Flame
The rating field reads “450 deg C, 300 Vac, Horizontal flame.” 450°C is the rated temperature; the record does not describe it as continuous, sustained or long-term. 300 Vac is the only voltage rating; no DC, peak or higher AC value applies. Horizontal flame is the flame classification. VW-1, FT1, FT2 and vertical flame are not Style-wide properties.
The rating is the same for both thickness groups. The 24–12 AWG requirements do not change the temperature, voltage or flame rating.
Optional Stainless Steel Alloy 304 Braid
The Shield entry reads: “Optional. stainless steel, alloy 304, applied as a braid over the treated glass braid.” It is a secondary construction option, not a requirement for 24–12 AWG. The record establishes its material, form and position only; it does not establish EMI attenuation, shielding effectiveness, chemical, corrosion, abrasion, crush or hot-spot protection, or mechanical reinforcement, and none is claimed here. Whether the option is required is stated in the RFQ.
Oven and Similar High-Temperature Equipment Wiring
The Use reads: “Wiring of ovens or similar high-temperature equipment where protected from mechanical abuse and where the acceptability, including current-carrying capacity, has been determined by Underwriters Laboratories Inc.” It has three parts:
- Wiring of ovens or similar high-temperature equipment: ovens are named directly in the Use. The record does not explain why that wording was chosen and does not list oven types or specific connections, so suitability for a particular design depends on the actual equipment and construction.
- Protected from mechanical abuse: exposed routing, abrasion locations, door pass-throughs, moving racks, field, building, tray and outdoor wiring fall outside the Use. Neither the glass braid nor the optional SS304 braid removes this condition.
- Acceptability, including current-carrying capacity, determined by UL: no current rating is assigned to any size from 24 to 12 AWG, and none is derived from AWG or general wiring-code tables.
The Style 5334 Use contains no repeated-flexing clause, and none is added here. Equally, the wire is not described as a high-flex wire.
24–12 AWG versus the 11–4 AWG UL 5334 Thickness Group
| Conductor size group | Composite Mica Glass, min avg wall | Treated Glass Braid, min avg thickness |
|---|---|---|
| 24 – 12 AWG (this page) | 17 mils | 5 mils |
| 11 – 4 AWG | 20 mils | 10 mils |
Two points in this table need clarification. First, each group’s values apply only to its own sizes: 12 AWG uses 17/5 and 11 AWG uses 20/10. Second, the record does not explain why the groups differ and does not state that the 20/10 group gives higher mechanical strength, current capacity, voltage capability or durability. Both groups share the same 450°C, 300 Vac, Horizontal flame rating and the same Use.
What Style 5334 Does and Does Not Define
For 24–12 AWG, the Style record defines the single-conductor construction; the rating (450°C, 300 Vac, Horizontal flame); the conductor form (solid or stranded); the insulation and braid (non-extruded mica with glass braid); the 17-mil minimum-average composite mica glass wall; the 5-mil minimum-average treated glass braid; the braid treatments; the optional SS304 braid; the marking field (General); and the Use.
The Style record does not define:
- conductor material, plating or strand construction
- conductor resistance or current rating
- minimum-at-any-point thicknesses
- finished outside diameter, tolerance or a combined wall
- the composition or manufacturing process of the composite mica glass
- any multiple-conductor assembly
- a repeated-flexing restriction, bend radius or service life
Common Procurement Errors
- Applying the 20/10 mil values of 11–4 AWG to 24–12 AWG.
- Treating 17 or 5 mils as nominal or point minimums.
- Using 17 + 5 mils as a finished wall or diameter basis.
- Describing the construction as thin-wall or compact without a qualified dimension.
- Specifying Style 5334 as a multi-conductor cable.
- Assuming a conductor material or plating.
- Assigning a current rating by AWG.
- Treating the optional SS304 braid as mandatory or as protection against mechanical abuse.
How to Specify UL 5334 24–12 AWG Mica Glass Wire in an RFQ
The Style fixes the single-conductor construction, the rating, the conductor forms, the 17/5 mil minimum averages, the braid treatments, the optional SS304 braid and the Use. The following should be stated by the buyer and confirmed for the ordered qualified construction, not filled with assumed values:
- AWG size within 24–12 AWG
- solid or stranded requirement
- conductor material and plating requirement
- detailed stranding requirement, if controlled
- finished OD or tolerance, if controlled
- Silicone Varnish or TFE Finish requirement, if controlled
- optional stainless steel alloy 304 braid: yes / no
- required marking
- quantity
- packaging
- required documents
- oven or similar high-temperature equipment type
- routed location
- mechanical-protection condition
- required current or end-equipment evaluation information
UL Marking and Documentation
Style 5334 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. 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.
