UL 5128 450°C Mica Glass Wire for Vietnam Export — 300V AWM Style 5128 Factory Direct

UL 5128 450°C Mica Glass Wire for Vietnam Export

UL 5128 is a mica tape insulated wire with a glass braid outer covering, rated 450°C and 300V AC under UL AWM Style 5128, produced under UL Follow-Up Service File No. E333030. UL 5128 and UL 5107 share an identical insulation system — multiple layers of crystalline silicate mica tape wrapped over the conductor, with a glass braid outer covering for mechanical protection — and the same 450°C continuous temperature rating. The single parameter that distinguishes UL 5128 from UL 5107 is voltage: UL 5128 is rated 300V AC versus UL 5107’s 600V AC, achieved through a thinner mica tape insulation wall construction that provides the dielectric strength required for 300V circuits while reducing overall wire diameter and material cost relative to the 600V construction.

The 300V voltage rating of UL 5128 is not a limitation for the majority of applications where it is specified — it covers single-phase 230V AC heating circuits (the most common voltage for single-phase industrial heating equipment in Vietnam), all standard 24V DC and 120V AC control and instrumentation circuits, and thermocouple signal leads operating at millivolt levels. The applications where UL 5128 is the correct specification rather than UL 5107 are precisely those where the circuit voltage is inherently within 300V, but the wire routing location inside the heated chamber imposes a 450°C ambient temperature that is the binding constraint on wire selection — not the voltage.

Vietnam’s industrial heating equipment sector generates consistent demand for UL 5128 dây mica 300V chịu nhiệt cao (mica 300V high temperature wire) from equipment OEMs assembling single-phase heating equipment for domestic use and export, from kiln builders routing thermocouple leads through high-temperature refractory structures, and from maintenance operations replacing degraded thermocouple extension wiring in operating kilns and furnaces. CableApex exports UL 5128 factory-direct CIF Ho Chi Minh City from Yangzhou.

Product Specifications — UL 5128

UL 5128 vs UL 5107 — Choosing the Right Mica Glass Wire

Applications in Vietnam

Thermocouple extension leads inside kiln and furnace chambers (Vietnam)

Temperature measurement and control is a critical function in all industrial kiln and furnace operations in Vietnam — ceramic kilns in Bình Dương and Đồng Nai, glass annealing lehrs in the Ho Chi Minh City industrial corridor, and metal heat treatment furnaces in Đồng Nai and Long An provinces all require accurate temperature monitoring at multiple points inside the heated zone. The thermocouple extension lead — the wire section that carries the thermocouple signal from the thermocouple junction inside the heated zone through the kiln or furnace wall to the temperature controller in the external panel — must be routed through the kiln refractory structure or furnace wall insulation, where the ambient temperature at the wire surface can exceed 400°C at the internal penetration point.

Standard thermocouple extension cable using polymer insulation — including silicone rubber, which is rated only to 200°C — cannot be used for this internal routing section. UL 5128 mica glass wire provides the 450°C insulation performance required for the kiln-side portion of the thermocouple lead, operating reliably at the millivolt signal level (well within the 300V rating) at sustained temperatures that would destroy any polymer insulation within the first few hundred hours of continuous kiln operation. Vietnamese kiln builders specify UL 5128 at 22 AWG to 18 AWG for thermocouple extension leads — the AWG range appropriate for the low-current signal circuit while minimising wire diameter for routing through narrow refractory wall penetration points.

Single-phase 230V AC heating element connections — Vietnam export equipment

Vietnam’s rapidly growing industrial equipment manufacturing sector — centred in industrial zones in Bình Dương, Đồng Nai, and Hà Nội — assembles a significant volume of single-phase industrial heating equipment for export to other Southeast Asian markets and for domestic Vietnamese industrial use. Single-phase industrial heating equipment typically operates at 230V AC at the heating element connection — the circuit voltage that determines the wire specification required for the internal wiring from the terminal block to the heating element terminal inside the heated zone. At 230V AC, UL 5128 (300V rated) is the correct and most cost-efficient specification — providing the necessary 450°C thermal performance at the heated zone routing location while avoiding the over-specification and higher cost of UL 5107’s 600V-rated thicker insulation wall construction.

Vietnamese equipment OEMs assembling single-phase industrial dryers, food processing ovens, laboratory drying ovens, and heat sealing equipment for export to the ASEAN market specify UL 5128 as dây mica xuất khẩu (mica export wire) for the internal element wiring in the heated zone. The UL 5128 compliance documentation referencing File No. E333030 satisfies the UL recognition requirement for internal wiring in equipment submitted for UL listing to serve the North American and international export markets.

Low-voltage control and signal wiring in high-temperature enclosures (Vietnam)

Modern industrial kiln and furnace control systems in Vietnam route a variety of low-voltage control and signal circuits from the external control panel into the heated equipment enclosure — 24V DC PLC I/O wiring for heating zone control, 4–20 mA analogue signal wiring for process instrumentation, and 0–10V DC feedback signals for power controller regulation. Where these control circuits are routed through or along the heated zone of the equipment — rather than in an external conduit run that bypasses the heated section — the ambient temperature at the wire surface inside the heated zone requires 450°C rated insulation despite the low circuit voltage.

UL 5128 is the appropriate specification for these low-voltage control circuits in high-temperature routing environments — the 300V voltage rating covers all standard industrial low-voltage circuit levels, and the 450°C mica tape insulation ensures that the control wiring maintains its insulation integrity through the heated zone for the full service life of the equipment without the progressive insulation degradation that silicone rubber wire would experience when operated continuously at temperatures above its 200°C rating.

Gas appliance burner zone wiring — Vietnam commercial kitchen and food processing

Commercial gas cooking equipment and industrial gas-fired food processing equipment in Vietnam — gas combination ovens in Ho Chi Minh City’s food service sector, gas-fired tunnel ovens in the bakery and snack food processing industry in Bình Dương and Long An industrial zones — use UL 5128 for the low-voltage wiring in the burner control zone where the gas ignition system, flame sensor, and gas valve solenoid connections are routed in proximity to the burner flame and the heated oven chamber wall. These circuits operate at 24V DC or 230V AC — within UL 5128’s 300V rating — but the burner zone ambient temperature at the wire routing location requires the 450°C mica insulation performance to ensure long-term reliability of the burner control wiring in continuous production operations.

Additional applications in Vietnam

• Heat treatment salt bath furnace thermocouple and control leads — Vietnamese metalworking facilities in industrial zones
• Industrial vacuum oven temperature sensor wiring — Vietnamese electronics and semiconductor equipment
• Rubber curing press instrumentation wiring inside the heated platen zone — Vietnamese rubber products manufacturing
• Continuous sealing machine heat zone control wiring — Vietnamese food packaging and plastic film processing operations
• Ceramic decoration kiln temperature monitoring leads — Vietnamese ceramic decorating and firing operations

Key Features

Ordering Information

Specify AWG, conductor type (nickel-plated recommended for sustained 450°C operation), and quantity. MOQ 500 m per AWG. Mixed AWG orders accepted. UL 5128 compliance documentation and RoHS Declaration supplied with every order. For 600V three-phase heating circuits at the same 450°C temperature class, see UL 5107. Sample from 10 m.

Why CableApex for Vietnam

CableApex manufactures UL 5128 mica glass wire under UL Follow-Up Service File No. E333030 in Yangzhou, China. Factory-direct export to Vietnam — CIF Ho Chi Minh City, 10–14 day transit. Full UL compliance documentation for equipment OEM qualification and maintenance procurement. No distributor margin on factory-direct orders. Contact us within 24 hours.

Please enable JavaScript in your browser to complete this form.

Company Name

Full Name *

Work Name WhatsApp

Work Email *

Phone / WhatsApp

Request a Quote