SEP 19 197 6968996 PREFATORY. The object of this book is to give in a convenient form the properties and dimensions of bare and insulated wires and cables used in electrical construction. No attempt has been made to describe the uses of wire in any of the applications of electricity. To go into this would require that the whole field of electrical engineering be covered. It is believed that some of the matter is new. All of the tables have been very carefully computed, and are believed to be correct. In nearly all cases the formulas and constants used in computing tables are given, so that the user can determine at once the basis from which the table was calculated. A considerable amount of work has been done in testing samples to determine the proper constants. In many cases this has taken more time than the actual preparation of the tables. It is hoped that the work will be acceptable to the users of electrical wires, and that some of the labor involved in the preparation of these tables will be saved to those using the book. JOHN A. ROEBLING'S SONS Co. TRENTON, N. J., February, 1906. PREFACE. This book of tables was first published in 1892, under the title of "TABLES FOR ELECTRICAL ENGINEERS." In 1897 the book was revised and given its present title, "WIRE IN ELECTRICAL CONSTRUCTION." In 1916 the book was revised and published under the same title. The preface of the second edition tells the object of the book, which is true of the third edition. Above all other things this is a collection of tables of the properties of copper wire. The resistance of a mil foot of copper at 20° C, or 68° Fahr. used in the three editions is as follows: 1892 edition 10.3517 ohms. The weights of copper wire were figured from the same formula d2 × .003027 = pounds per 1000 feet in both the 1897 and the 1916 editions. The resistance of copper wire in the tables in all editions is figured at 100% conductivity. October, 1916. |