Electric Wiring Tables

Abstract

MR. MAYCOCK'S pocket-book of tables should prove very useful to those electrical engineers whose work consists solely of wiring and fitting. It contains in a very convenient form tables of all the quantities likely to be wanted in such work, and has the advantage of being quite up to date, the values in the tables of the safe currents, resistances, &c., of copper conductors being calculated on the basis of the recommendations of the Institution of Electrical Engineers Committee on Copper Conductors, which only made its report at the beginning of this year. It is, perhaps, a disadvantage of the pocket-book that it is so limited in its scope, and we are inclined to think that it would appeal more strongly to the particular class of electrical engineers for which it is designed if more general information were included. A summary of the fire insurance rules should certainly be inserted, and it would be useful if some idea were given of the approximate costs of wiring on the different systems alluded to in the section on “Systems of Wiring.” Some of the tables are simply “Ready Reckoners”; for example, the tables of “Price and Length of Conductors” give the prices of different lengths of conductors calculated from the price per yard, and would apply equally well to wood-casing and metal-piping, a fact which should be indicated in the title of the table. The table giving the current taken by different numbers of lamps working at different pressures and different efficiencies is a very useful one, particularly now that high-efficiency lamps are being brought forward. The same can hardly be said of the list of towns supplying on the alternate current system, since no details are given as to pressure and frequency. The usefulness of the pocket-book would be considerably increased by the addition of an index.