Railway Sector

“ At that time, most electrical professionals were still learning about the larger coefficient of thermal expansion of aluminum compared to that of copper. The result was aluminum-bodied lugs used to terminate copper wire operated successfully, while copper-bodied lugs used to terminate aluminum wire failed. Three entire series of branch circuit device termination types were tried and failed: copper (C), copper/aluminum (CU/AL), and copper/aluminum/revised CU/ALR) before a workable design, copper/aluminum/rev. “

II (CO/ALR) was achieved. Larger aluminum wire sizes terminated in copper lugs almost always presented problems, while the use of aluminum-bodied lugs reduced those problems, except when moisture entered in the formula.