This SAE Recommended Practice provides general guidelines on the material selection, construction and qualification of components and wiring systems used to construct wiring systems for Heavy Duty Vehicles The guidelines are limited to primary wiring systems of less than 50 V and includes cable sizes American Wire Gage 20 to AWG 4 on heavy-duty on-highway trucks. The document identifies appropriate operating performances requirements. This document excludes the male to female connection of the SAE J560 connectors.