SAE J1128 is a key U.S. automotive wire standard developed by the Society of Automotive Engineers (SAE) for low-voltage electrical systems in passenger vehicles, trucks, and off-road equipment. This American specification defines the construction, performance, and testing requirements for primary wires used in 12V or 24V systems.
SAE J1128 covers multiple wire types including GPT, GXL, SXL, and TXL, which differ in insulation thickness and temperature resistance. These wires are commonly used for vehicle control circuits, lighting, dashboard electronics, engine compartments, and power distribution.
Designed for harsh automotive environments, J1128-compliant wires offer excellent abrasion resistance, chemical resistance, flexibility, and thermal stability, with operating temperatures typically ranging from -40°C to +125°C, depending on insulation type.
As a widely recognized U.S. specification, SAE J1128 wire is trusted by OEMs, wire harness manufacturers, and aftermarket installers for its consistent quality and durability. It plays a critical role in designing reliable automotive electrical systems and meets both performance and safety requirements across the global automotive industry.