Wiring Harness News WHN Sept-Oct 2020 WHN Sep-Oct 2020 - Page 46

46 SEPTEMBER/OCTOBER 2020 Wiring Harness News INDUSTRIAL INFO-TAINMENT Light Weight and Normal Weight Wire Construction in Aerospace Wiring By Michael Traskos Lectrome ______________________________ Saving weight is a large part of any aircraft design. Naturally, the electrical system is not exempt from the goal of shaving off a couple of pounds. This often comes in the form of looking for lighter connectors, lighter clamps, and also lighter wire constructions. Those that have done this have undoubtedly come across two classifications of wire construction: “Normal weight” and “light weight”. Of course, if the EWIS has to go on a diet, then the “light weight” construction looks like a good substitute for the “normal weight” … after all, why would the wire be called “light weight” if not for satisfying weight requirements. As with all parts of the EWIS, going to the light weight construction is not a simple swap. There are performance changes and requirements that must be addressed with making the change. High Level The difference between light weight and normal constructions is narrowed down to the insulation thickness. Comparing a 20AWG normal weight wire to a 20AWG light weight wire, the conductor size may remain the same, but the insulation thickness will not. In light weight constructions, to reduce the weight, the insulation thickness is decreased. In many cases, the light weight construction will have a wall thickness of 5 – 7 mils with the normal weight construction having a construction greater than 7 mils. Save weight, lose what? As with everything in engineering, there is a tradeoff for everything done. The use of the light weight wire construction is not without costs. For this example, we shall compare the performance requirements of AS22759/193 and /195. These are the light weight and normal weight Table 1. Test requirements for both construction types.