The ability to withstand extreme temperatures is vital for aerospace components, including electrical fittings. The BS EN 3475 series discusses electrical cables used for aerospace applications.
BS EN 3475-705 is a European Standard that specifies the process to be applied for measuring the contrast of wire and cable identification markings against the background of the unmarked wire insulation. BS EN 3475-705 has been developed primarily to define a reproducible process of contrast value determination for use both to determine the intrinsic laser markability of wires at the time of manufacture or later, and to enable electrical wiring systems manufacturers to ensure that the whole process of wire marking is carried out to the required standard.
BS EN 3475-705 on Contrast measurement testing for aircraft electrical cables is useful for:
It is a requirement within the aerospace industry that all wires and cables within an aircraft electrical system are identified with a circuit identification code at regular intervals down the length of the wire. Various marking methods are used for marking these identification codes on to the surface of electrical wires or cables including ink-based and laser-based processes.
The legibility of the markings is dependent upon the process used and the insulation medium. Minimum standards of contrast are required to facilitate reading back of the identity codes.
BS EN 3155-023 provides you with details for conducting the test such as the required apparatus, the measurement, and the process. Detailed diagrams of the lighting equipment, as well as contrast measurements on wire sample markings, have been provided for your reference.
EN 3475-705