Electrical wiring in modern real estate has become the same mandatory engineering system as plumbing, sewerage and ventilation. The linear part of this system is formed on cables and wires, which are divided into two main types: flexible and rigid.
Main design features of flexible and rigid wires
The electrical wire in Figure 1 always contains a conductive core and insulation, which is actually provides normal conditions for the functioning of the core as a means of transferring current from the generator to load.
The core of the rigid wire is made in the form of a single wire of the required cross-section; to obtain a flexible core, several wires of a smaller diameter are taken and twisted together. In this case, several layers can be used, as their number increases, the flexibility of the wire increases with a constant cross-section.
Insulation of various colors is applied to the core to identify the purpose of each wire in the finished cable product. Then the individual wires are fastened to each other (zip-cord structure) or assembled into a core, if necessary, they are supplied with additional coatings and a common sheath.
Applications for rigid and flexible wires
Rigid wires have both limited flexibility and withstand relatively small number of bend-unbend cycles without breaking their consumer properties. With this in mind, they should be used in the stationary part of the wiring. For example, if there is enough space, machines and RCDs for various purposes in the dashboard are switched using rigid wires, and the dashboard is also connected to sockets and overhead lighting terminals.
The focal area of application of flexible wires in an apartment is connecting to numerous sockets household consumers from an iron, an electric kettle and a refrigerator to a music center and a computer, picture 2. Any extension cord is also equipped with a flexible cable, regardless of the number of outlets. In shields, they are used to implement interconnections at a high packing density.
The downside of the resistance of a wire with stranded conductors to multiple bends is a higher cost. This is determined by the high cost of manufacturing thin wires and the complexity of forming a core from them, and also the need to use thicker insulation to obtain the required mechanical strength. Therefore, the use of flexible wire in the linear part is not justified in terms of costs
Features of installation of rigid and flexible wires
Wires and cables pre-terminated with connector elements that are similar to the product in Figure 2 are less common. In all other cases, the wires are connected to the terminals. In this case, it is enough to simply remove the insulation from the hard wire to the required length. When working with a flexible wire, after stripping, it is imperative to put on a crimp ferrule, one of the options of which is shown in Figure 3. Its presence guarantees a large contact area and noticeably reduces the contact resistance.
Conclusion
As you can see, the main criterion for using rigid and flexible wires is the nature of the load: static or movable. In this case, a flexible wire can be used instead of a rigid one if it is impossible or difficult to lay the latter. The use of a rigid wire instead of a flexible one is strongly discouraged due to the danger of quick failure.