A vehicle harness drawing rarely says “1.0 sq mm wire”. It says FLRY-B, AVSS, GXL or ISO 6722 Class C, and each of those codes points to a specific standard, insulation and temperature rating. Substituting one for another without checking can put a PVC wire into a location specified for cross-linked insulation, with failure following months later. The charts below show where each code comes from.
ISO 6722 temperature classes
ISO 6722-1 is the international standard for single-core cables in road vehicles. It classifies cable by the temperature range it withstands, and separately by wall thickness (thick wall, thin wall and ultra-thin wall).
| Class | Temperature range | Typical location |
|---|---|---|
| A | minus 40°C to 85°C | Cabin and body wiring |
| B | minus 40°C to 100°C | Cabin, general chassis |
| C | minus 40°C to 125°C | Engine compartment, near heat sources |
| D | minus 40°C to 150°C | Engine and exhaust-adjacent routing |
| E | minus 40°C to 175°C | High-temperature zones |
The standard continues to classes F, G and H (up to 250°C) for special applications. The class describes the insulation’s temperature endurance; it does not replace a check of current rating and voltage drop for the circuit.
Standards and wire types
| Standard | Origin | Wire types it defines |
|---|---|---|
| ISO 6722-1 | International | Single-core cables by temperature class A to H and wall thickness |
| SAE J1128 | North America | Low-voltage primary cable: GPT (PVC), and SXL, GXL and TXL (cross-linked polyethylene, standard, thin and extra-thin wall) |
| SAE J1127 | North America | Low-voltage battery cable |
| SAE J1939/15 | North America | Unshielded twisted pair CAN data cable for heavy vehicle networks |
| JASO D 611 | Japan | Thin-wall automotive cable, including AVS and AVSS types |
| JASO D 618 | Japan | Test methods for automotive low-voltage cable |
| JIS C 3406 | Japan | AV type low-voltage automotive cable |
| DIN 72551 Part 5 and 6 | Germany | FLRY thin-wall PVC vehicle cable (FLRY-A and FLRY-B differ in conductor stranding) |
| IS 2465 | India | Cables for motor vehicles, including battery cable |
Reading the codes together
Harness drawings from Japanese vehicle platforms tend to call AVS and AVSS types; European platforms call FLRY and ISO 6722 classes; North American and many commercial vehicle platforms call SAE types. A drawing that names one family can often be met by an equivalent wire from another only with the vehicle maker’s approval, because wall thickness, conductor stranding and test methods differ. The safe rule is to quote the exact type on the drawing and raise any substitution as a formal deviation.
What APAR makes
APAR manufactures automotive wires in 0.5 sq mm to 2.5 sq mm and SAE 28 AWG to 6 AWG, covering ISO 6722 types A, B, C, D and E, e-beam cross-linked GXL, TXL and SXL wires, FLRY-B, AVS, AVSS and AV types, CAN bus cable to SAE J1939/15, and battery cables to IS 2465, SAE J1127 and J1128 and ISO 6722. See automotive wires and cables and battery cables and accessories for the range, and the battery and automotive cable selection guide for sizing low-voltage DC runs. Complete assemblies are covered under harness for automotives and EV.