Considerable attention was given to breaking the joints of the ducts properly, so as to maintain throughout the conduit lines the greatest break possible. The joints in each superimposed line were broken at half the length of the individual pieces of conduit, the joints in lines in the same horizontal plane being broken at one-quarter the length, thus preventing any joints from touching one another either at the sides or corners, which tended to prevent a burn-out on one line from being communicated to another. There was some little difficulty at first in maintaining the breaks, owing to slight variations in the lengths of the conduit, but after a very short time both the workmen and the inspectors became very expert at this and in the proper use of short lengths to maintain the spacing; after the first few weeks there was little if any difficulty in attaining at all times almost perfect results. The method of making the breaks is shown in the photographs and by the isometric sketch at _F_, Fig. 15. All the conduits used on this work were furnished by the Great Eastern Clay Company, and were made at its factory at South River, N.J., where they were inspected before shipment. The mandrel used in the final rodding was made as shown at _G_, Fig. 15, the larger size being used for all lines. The rods for pushing it through the conduit lines were made of 6½-ft. lengths of ordinary 1-in. wrought-iron pipe with extra long (3-in.) couplings. The lines were rodded in both directions from alternate manholes, thus avoiding uncoupling the rods and allowing every pull to be effective in pushing the mandrel through the ducts. [Illustration: Fig. 15. [Full Page] ELECTRICAL CONDUITS: METHODS OF LAYING, RODDING, ETC. A. FORK ENDED STEEL BONDS FOR CONDUITS. B. SEQUENCE OF METHODS OF BUILDING BENCH-WALL PROPOSED WHEN USING EXPANDED METAL BONDS. C. ISOMETRIC DRAWING OF EXPANDING MANDREL. D. DETAILS OF “WEASEL” Used for gripping disconnected pipe rods in conduit E. CUTTER FOR REMOVING OBSTRUCTIONS IN CONDUITS. F. ISOMETRIC SKETCH SHOWING METHOD OF BREAKING JOINTS AND POSITION FORKED BONDS. G. PLAN AND SECTIONS OF EXPANDING MANDREL. INDEX +-----+------------+-------------+ | | Multi-Duct | Single-Duct | | | Mandrel | Mandrel | +-----+------------+-------------+ | _A_ | 3¼” | 3⅜” | | _B_ | ¾” | ⅞” | | _C_ | 2½” | 2⅝” | +-----+------------+-------------+ Note End pipe connections may be changed to suit connections of rodding outfit, care being taken to use a connection which will not split and expand the mandrel if it should be driven back into it, in attempting to ram the mandrel back when stuck in a duct. Connection at Head End may be dispensed with, if the mandrel is threaded through ducts by rods attached to the trailing end.]