NASA/TM-102179, NASA TECHNICAL MEMORANDUM: SELECTION OF WIRES AND CIRCUIT PROTECTIVE DEVICES FOR STS ORBITER VEHICLE PAYLOAD ELECTRICAL CIRCUITS (JUN 1991)

NASA/TM-102179, NASA TECHNICAL MEMORANDUM: SELECTION OF WIRES AND CIRCUIT PROTECTIVE DEVICES FOR STS ORBITER VEHICLE PAYLOAD ELECTRICAL CIRCUITS (JUN 1991). This document has been prepared by the JSC Engineering Directorate, Orbiter Electrical Wiring and Installation Subsystem to aid in the electrical design of payloads to be carried aboard the Space Transportation System (STS) Orbiter vehicle. It will guide designers in selecting wire sizes and associated protective devices that are acceptable by JSC for Orbiter-borne payloads. Although the information presented is generally applicable to generic aerospace applications, it is limited in scope and is primarily intended to serve the purpose noted above. Therefore, only the ambient pressures and temperatures are addressed that are normally experienced by an Orbiter-borne payload during ground checkout and while inside the Orbiter payload bay. Part numbers and parameters for various protective devices in the appendix are also Orbiter-specific. If the designers choose to use other than "Orbiter-approved" parts they may easily find corresponding values for their specific device which can be substituted for values listed in the tables and used in their calculations. Many circuits and installations in a design will have more than one configuration that can fulfill all essential safety and reliability needs. This document does not establish requirements, but establishes guidelines form which deviations can be evaluated. Users will be required to identify for individual evaluation only those circuits that do not meet or that exceed the limits established in this document. The result of following this guide will be the delivery of a payload for flight in the Orbiter that will not conflict with the wiring and circuit protection requirements imposed by the Orbiter Payload Safety Panel. A design that is acceptable, based on these guidelines, must still be evaluated by the JSC Materials Branch for insulation compatibility. Data used in this document is derived from Eagle Engineering's report, "Wire Size Determination for Aerospace Applications."