Fig. 22.
On the contrary, if the burners fail to work and no sign of a short circuit can be thus obtained, it is evident that a wire is broken or a screw is loose.
To locate a break, connect up the bell as just described and attach the testing wire to the switch with all levers closed; this is actually putting the bell in series with the battery, coil, and ground. Then hunt for the break. Take a long piece of wire and fasten one end to a ground pipe. Then touch the other end to the circuit wire in the cellar as far as you can go, baring the insulation in spots, but carefully re-insulating it again. If there is no break in the cellar, the bell will ring loudly at each contact. Next, proceed to the next floor and repeat the operation, gradually working away from the battery. As soon as you pass the break, the bell will fail to respond. Two persons here are better than one, as it may be necessary to go quite a distance from the bell before finding the trouble.
Fig. 23 shows details of the wiring from the hall light to the two push-buttons. A wire is run right down from the top push T, middle connection, past the lower push L, where a similar branch joins it, until it reaches the section switch. The lighting and extinguishing wires from the lower push run up and are joined on to the similar wires from the top push, which latter wires go directly through the floor and ceiling to the automatic burner A.
Fig. 23., & Fig. 24.
Fig. 24 is the detail of the wiring for the cellar automatic burner A, from the push P, and is so clearly shown as not to require further explanation.
The secret of success in gas-lighting work is careful wiring. The platinum tip of the vibrating rod is often bent, either by accidental blow or by the continual hammering against the tip on the collar. This often causes an open circuit when the lighting armature refuses to buzz. Again, soot will form, causing weak action owing to imperfect contact. Examine, adjust, and clean; here, as in all electrical work, contacts must be clean.
In general wiring, use weatherproof office wire, or, better still, well-made electric light wire. For ordinary house work No. 16 B. & S. gauge is preferable; smaller wire means higher resistance and less current at burner. For braided office wire, No. 16 runs about 95 feet to the pound, No. 18 about 135 feet to the pound. The cheaper grades of wire without the patent finish or extra insulation are not worth using; sooner or later trouble will ensue, and once a house is wired, it is no pleasant job to hunt trouble, especially if the wire was put on before the plaster. In modern buildings in large cities, the use of conduit tubes has become general, but the handling of these conduits comes more under the province of the electric-light wireman and less within the scope of these pages.