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use. Some cotton rags or waste, and a sponge, should be included if wet cells are employed. Glass battery jars cannot well be carried with the other materials, and if any of those in use are found to be broken or cracked, a separate trip should be made.
Proper Ground Connections.—Lightning arresters are useless unless properly grounded, and as the general practice in installing residence sets is to use a water or gas pipe for a ground, it is important that a positive connection should be made with minimum trouble and preferably without soldering. Several clamps have been devised that only call for scraping the pipe to insure a bright contact surface between the connection clamp and pipe that gives very good results in practice and which are cheap, simple in construction and easy to install.
Fig. 622.—Practical Ground Clamps. The Vogel clamp, shown at Fig. 62a, A, is designed for grounding telephone, telegraph, and
signal lines and is being universally adopted by the leading companies in the field. It is selfcontained, there being no detachable parts to become lost, and it is claimed it can be adjusted in less than a minute, and is cheaper and more permanent than a wrapped joint. As most ground connections are made to a water pipe, it is difficult to make a solder connection, therefore the use of ground clamps.
The band of the clamp is of 98 per cent pure, soft copper and heavily tinned with pure tin, the clamping piece is of spring brass and bolts and nuts of brass. The clamp remains tight under expansion or contraction of the pipe—the spring tension of the clamping piece does the trick. This clamp is adjustable, fitting from one-half to two inch pipes or cables. It has been subject to the severest tests in service and will safely carry a discharge of 300 amperes.
The Blackburn clamp is shown at B, Fig. 62a, and is similar in general design to that previously described except that a set screw is used to tighten the contact band around the pipe. A nut on the clamping screw insures that the wire will be properly secured to the ground clamp, and the band is provided with a series of holes so it can be adjusted to different sizes of pipes.
Simple Wire Skinner.- A very useful and simple tool for all wiremen is the P. and G. wire skinner, which is illustrated at Fig. 62b, as well as the method of using it. It consists of a piece of
spring steel bent in the form of a pair of tweezers about 31/2 inches long, and having two ends bent at right angles to the main sides of the instrument. These ends are provided with a sharp cutting surface to strip the insulation from heavy wires while the nicks are for duplex wires. It not only strips off the insulation but will separate the two wires of a duplex conductor with one pull. It can be used with any kind of insulated wire, including weather proof, rubber covered, cotton covered, braided, lead covered, lamp cord, etc., : without cutting or otherwise marring the wires.
Fig. 62b.-P. and G. Wire Skinner.
Examining Partition Interiors.-A pocket flashlamp and a small mirror will be found of considerable value in inspecting the interior of a wall or partition that would ordinarily be inaccessible. For fishing wires, retrieving cable and inspecting finished work this use of a lamp and
mirror provides a labor saving kink. The mirror has only to be introduced to the outlet hole in the wall, the flashlight and eye being held behind it as illustrated in Fig. 62c. The mirror reflects the lamp light into the space and the beam illuminates any objects within range. As the object is illuminated, the image will be reflected back to the eye by the mirror. The usefulness of this little device is as great as its simplicity.
FIG. 62c.—Examining Partition Interiors. Extending Radius of Action of Telephone Bell. -Frequently the telephone is not heard in all portions of the house when it rings and many calls are not answered because of this. If the telephone is in a lower hall, it can seldom be heard upstairs. An ingenious and cheap extension that will make the ringing of the telephone audible is illustrated at Fig. 62d. This device consists of two
Dry Batteryl Fig. 62d.—Extending Radius of Telephone Be!l. copper strips, DD, set into two binding posts and attached to the wall above the bell. The lower portions of the strips are interposed between one of the gongs and the clapper. As soon as the telephone bell rings it makes and breaks the circuit of an electric bell, B, and battery, C, that can be located in any part of the house and at any distance from the telephone bell, A.