Figure 5-32. - Portable cord splices.
Large stranded cables (fig. 5-33) are not often used in residential wiring; however, they are used in other situations. such as for battery jumper cables and welding cables. When jumper cables or welding cables are broken, they can be temporarily repaired, as shown in figure 5-33.
Because solderless connectors (such as plastic end caps) are time-saving and easy to use. the electrician no longer needs to solder each and every splice. It not only takes less time to make a solderless connection but also requires less skill. However. soldering is still the most reliable method of joining pieces of wire, and every electrician should learn how to solder.
Once the decision is made to solder an electrical splice and the insulation has been stripped off the wire, the splice should be soldered as soon as possible. The longer the splice is exposed to dirt and air. the more oxidation will occur thus lessening the chance of a good solder joint. Clean metal surfaces. free from oil. dirt. and rust (oxidation) are necessary to allow the melted solder to flow freely around the splice. The surfaces may be cleaned by using light sandpaper or an emery cloth or by applying flux to the joint as it is heated
Figure 5-33. - Gable splices.
Solder usually comes in either bar or wire form and is melted with heat from soldering devices. such as a soldering iron. soldering gun. or propane torch (fig. 5-34).
The electric soldering iron and soldering gun are used when electrical service is available. The propane torch is used to solder large wires or when there is no electricity at the jobsite. Whatever method you use, be sure to apply solder on the side of the splice opposite the point where you apply the heat. Figure 5-35 shows the three methods of soldering. The melting solder will flow toward the source of heat. Thus, if the top of the wire is hot enough to melt the solder, the bottom of the wire closest to the heat source will draw the solder down through all the wires. Allow the splice to cool naturally without moving it. Do not blow on the joint or dip it in water to cool it. Rapid cooling will take all the strength out of a solder joint. Once it is cooled, clean off any excess flux with a damp rag, then dry and tape it.
Avoid breathing the fumes and smoke from hot solder. Some solder contains lead which if inhaled or ingested can cause lead poisoning. Avoid prolonged skin contact with fluxes. Your supervisor will give you a Material Safety Data Sheet (MSDS) with the precautions for solder and flux.
Taping is required to protect the splice from oxidation (formation of rust) and to insulate against electrical shock. Taping should provide at least as much insulation and mechanical protection for the splice as the original covering. Although one wrap of plastic (vinyl) tape will provide insulation protection up to 600 volts, several wraps may be necessary to provide good mechanical protection.
When plastic tape is used, it should be stretched as it is applied. Stretching will secure the tape more firmly. Figures 5-36 through 5-39 show the most commonly used methods of taping splices.
Safety for the electrician today is far more complicated than it was 20 years ago. But with proper use of today's safeguards and safety practices, working on electrical equipment can be safe. Electricity must be respected. With common sense and safe work practices, you can accomplish electrical work safely.Continue Reading