Connectors and Wiring Harness Requirements Wire harnesses shall not be located in close proximity to oil and fuel fluid fill areas or below fuel and oil filter locations. If these locations cannot be avoided, additional protective covers and shields must be provided to protect the harness. Harnesses shall be located a minimum of 50 mm from high heat sources (e.g. exhaust manifolds, turbochargers, hydraulic components, etc.) to avoid insulation and/or connector deterioration. 5.2.2 Maintenance Considerations The maintainability of the wiring system shall be an important consideration in the selection, design, and installation of harnesses, cable assemblies, and other wiring system components.
All wiring components shall be accessible, repairable, and replaceable (i.e. connector terminals). High-pressure wash systems are now in frequent use by maintenance people. When locating electrical connectors, place them in accessible locations while using other physical elements for protection and prevention of direct exposure to wash systems (e.g. brackets, housings, sheet metal structure, etc.). Where direct exposure to high pressure wash systems cannot be avoided, protective shields will need to be designed and installed. 5.2.3 Appearance The primary purpose for the wiring system is to provide electrical and electronic component function.
There is, however, another important and intangible value to consider when designing the wiring system. The appearance of the wire harness and its routing path should reflect an orderly, well-thought-out design plan. A poorly executed plan can have a negative impact on customer perceptions of the entire product. Use the product’s horizontal and vertical lines for routing paths. Design preformed bends into large harnesses to facilitate product assembly and improve appearance. Use other product elements to shield or hide the harness from view. Benchmark new automotive product applications for ideas.
5.2.4 Harness Bends Routing of the harness should insure connector seals are not stressed because the harness curvature is too close to the connector. This applies to routing of customer lines on or near the engine harness as well as the ECU customer connector (J1/P1). The minimum bend radius for a braided wire harness as measured from the inside of the bend shall be four times the outer diameter of the harness. Tighter bends are possible if the bend is preformed during harness manufacture. The bend radius size and location must be specified on the wire harness drawing. Bends in jacketed cables shall be based on manufacturer recommendations.
A bend must not adversely affect the operating characteristics of the cable. For flexible coaxial cables, the bend radius must not be less than six times the outside diameter. For semi-rigid coaxial cable, the bend radius must not be less than ten times the outside diameter of the cable. The minimum bend radius for flexible conduit must be six times the outer diameter of the conduit. Conduit bends shall not cause internal chafing of the wiring. A P P L I C A T I O N A N D I N S T A L L A T I O N G U I D E 33