(AET) Study Guide - NCATT

Page 39 of 5121. Use of Safetying Devices NCATT Training Standard Level (1a)(b) Shear WireObjective:Identify simple facts about use of shear wire.Content – Shear Wire:Explain the use of shear wire with reference to the following terms:• Shear Wire—Type of 0.20 inch diameter safety wire made of copper or brass. Shear wireis used for safetying emergency equipment and is designed to break when a force isapplied.• Emergency Equipment using Shear Wire—Includes the following:o Switch handles.o Guards covering handles used as exits.o Fire extinguishers.22. Aircraft Wiring NCATT Training Standard Level (A)(a) MulticonductorObjective:Identify basic facts and terms about use of multiconductor aircraft wire.Content – Multiconductor:Explain multiconductor aircraft wire and its uses with reference to the following terms:• Multiconductor Aircraft Wire—Two or more insulated wires in the same jacket.• Use of Multiconductor Aircraft Wire—Used for aircraft electrical power distributionsystems.• Sleeving Types—Includes vinyl sleeving, nylon sleeving, silicon rubber, and siliconfiberglass.• American Wire Gage (AWG)—Wire sizing standard. As the gage numbers become larger,the wire diameters get smaller. Wire sizing factors include the following:o Allowable power loss.o Permissible voltage drop.o Current carrying ability.• Conductors—Includes conductors made of copper and aluminum. Silver is veryexpensive, but it is sometimes used for conductors. Conductor characteristics include thefollowing:o Copper Conductor Characteristics—Copper conductors have higher conductivitythan aluminum. Copper conductors are more ductile, have relatively high tensilestrength, and are more easily soldered than aluminum. However, copper conductorsare more expensive and heavier than aluminum conductors.o Aluminum Conductor Characteristics—Aluminum conductors have 60% of theconductivity of copper. They weigh less than copper.• Conductor Plating to Prevent Corrosion (Oxidation)—Includes tin, silver, and nickel.Copyright © 2008 by the National Center for Aircraft Technician Training. All rights reserved.Individuals may download, print, and make copies of this documentfor their own personal use. Commercial use prohibited.