Automotive Wiring, Electrical and Flame Retardancy

If the interior's technical contradiction is "multiple indicators constraining one another", then the difficulty of electrical and wiring parts is more direct:flame retardancy is a hard requirement, and it has to be satisfied together with aging resistance. After NEVs pushed voltage to 1500 V, with larger currents and higher temperature rise, the halogen-free, low-smoke + long service life combination requirement for wiring-harness sheaths, electrical connectors and battery-pack housings has risen significantly.

NEV high-voltage wiring harness and charging cable — High-voltage harnesses and charging cables face significantly higher combined requirements for halogen-free flame retardancy, aging resistance and weather resistance than conventional low-voltage harnesses

1. Standards and requirements for wiring and electrical parts

System	Standard	Core requirement
Low-voltage harness flame retardancy	ISO 6722, FMVSS 302 (interior)	Horizontal burning-rate requirement; cables additionally carry the VW-1 vertical burning rating
High-voltage harness	ISO 19642, GB/T 25085/25087, UL 758	1500V DC flame retardancy and aging resistance; temperature resistance 125℃/150℃/180℃ by class
Bus and truck cable flame retardancy	UN/ECE R118 Annex 10	Self-extinguishing within 70 s, top insulation retained ≥50 mm
Charging cables / connectors	IEC 62196-2, SAE J1772	Flame retardancy, -30 to +50°C endurance, UV weather resistance, >10,000 insertion cycles
Material flame-retardancy rating	UL 94 V-0 / V-1 / V-2	Rated by wall thickness; harness sheaths and connector housings mostly require V-0
Battery-pack housing	GB 38031-2025 (mandatory from 2026-07-01)	Thermal propagation "no fire or explosion within 2 hours"; newly added bottom impact and post-fast-charge-cycle short circuit

2. The flame-retardancy vs. weather-resistance conflict, and Tiangang's solution

2.1 Why "flame retardant + conventional HALS" drag each other down

Common flame-retardant systems (halogenated flame retardants, phosphate esters, intumescent flame retardants APP/MCA) and their processing can all introduce acidic by-products. Conventional HALS, meanwhile, is an alkaline hindered amine - it neutralizes with these acidic substances, causing the HALS to deactivate early, and weather resistance falls with it.

This creates a dilemma: add flame retardant and weather resistance suffers; leave it out and the mandatory standard is not met.

2.2 NOR structure: resolving the conflict at the chemical-structure level

N-OR (N-alkoxy hindered amine) structure's key feature is low alkalinity and no neutralization with acidic substances, so it stays active in systems containing flame retardants or acidic components. Tiangang has two products in this direction:

Product	Chemistry type	Key metrics	Applicable scenarios
FR-810A Polymeric halogen-free flame retardant	Polymeric NOR-HALS	Flame retardancy + light stabilization + long-term thermal stabilitythree effects in one; recommended loading 0.2–1.2%; low volatility, low migration, low extraction; compliant with REACH / TSCA / FDA; recommended processing temperature ≤250°C	Battery-pack housings and module brackets, halogen-free flame-retardant LGF-PP, harness sheaths, PP fibers and nonwovens
XT-8 High-molecular-weight NOR light stabilizer	High-molecular-weight N-OR HALS	Resistant to sulfur at 3000-7000 ppm and chlorine at ≤850 ppm; a China-original structure with a CAS number; low alkalinity and low migration, usable alone or blended with HS-625	Blends containing acidic components, agricultural film and other harsh environments; can serve as the weather-resistance component in flame-retardant systems
HS-112 Low-molecular-weight liquid NOR	Low-molecular-weight N-OR HALS	Dynamic viscosity 3000 mPa·s (20°C); miscibility >50% in most common coating solvents; recommended loading 0.5-2% (can be blended with 1-3% UV absorber)	Automotive and industrial coatings, and processes requiring liquid feeding

A practical value of FR-810A: one fewer additive

The conventional approach is "flame retardant + stabilizer": two material codes, two loading controls, two weighing error sources. FR-810A merges flame retardancy, light stabilization and thermal stabilization into one product, reducing material codes and compounding steps while reaching the same flame-retardancy rating - a tangible cost saving in an automotive supply chain that demands batch consistency and controlled change.

3. Other electrical-related materials

Part	Material direction	Support Tiangang can provide
Battery-pack tray / underbody guard	Long-glass-fiber reinforced flame-retardant PP (LGF-PP + halogen-free flame retardant)	The N-OR system does not fail in acid; FR-810A can raise the flame-retardancy rating at low loadings
Battery module brackets / connector housings	Glass-fiber reinforced halogen-free flame-retardant PA6/PA66	XT-8 resists acidic environments; blended with AO-168 to improve long-term thermal stability
High-voltage connectors	Flame-retardant + hydrolysis-resistant PBT, PPA	Low-alkalinity NOR system, avoiding conflict with acidic flame-retardant by-products
Low-voltage harness sheaths	PVC / XLPE / TPE / halogen-free flame-retardant systems	AO-B215 and other blended antioxidants protect the process and long-term thermal stability
Automotive coatings / varnishes	Acrylic, polyurethane (water- and solvent-borne)	HS-3310 composite UV light stabilizers; HS-112 liquid NOR

For the complete flame-retardant and electrical-parts material list, see ④ NEV-Specific Materials and ⑤ Selection Guide.

Last Updated: 2026-10-20

Certifications

National High-Tech Enterprise
Vice Chairman Unit, China Plastics Processing Industry Association (CPPIA)
Vice Chairman Unit, Agricultural Plastics Branch, China Agricultural Plastics Application Technology Society
Member, Ageing Methods Subcommittee, National Technical Committee on Plastics (SAC/TC15/CS5)
Member, Society of the Plastics Industry (SPI), USA

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