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Which cable is better - flexible or rigid?

Which cable is better: flexible or rigid? When planning electrical work, in particular when it is necessary to select cable and wire products, the question arises of choosing between a flexible and a hard cable. In this article, we consider which cable better: flexible or rigid, depending on local conditions.

First, consider what a flexible and rigid cable is. The flexible cable is multi-core, which provides it with sufficient flexibility. A rigid cable is single core, that is, its conductive core consists of one conductor.

The main distinguishing feature of a flexible cable from a rigid one is the possibility of bending it an unlimited number of times, as well as the ease of bending.

Mono-core cable is not intended for frequent bends, it can be bent a certain number of times, after which its conductive core will break. For example, a new copper rigid cable is able to withstand 80 bends, and aluminum - 12 bends. Over time, the fracture resistance of a single-core cable decreases.

Based on this, we can conclude that the flexible cable is selected if it is necessary to connect mobile power consumers. A hard cable is preferred if the power receivers connected to the power supply have a fixed position, that is, they are not subject to constant movement.

Below we consider the features of using flexible and rigid cable in everyday life and in electrical installations.

Flexible and rigid cable in home wiring

The electrical wiring of the apartment provides power to sockets, switches and lighting devices. These elements have a fixed position, therefore, for the installation of home wiring, they prefer a rigid cable. But in this case, it is not forbidden to mount the wiring with a flexible cable.

If the flexibility of the cable in home wiring does not matter, then accordingly there will be no difference in the operation of the flexible and rigid cable. But when choosing between a flexible and a rigid cable, the time and material costs of installing electrical wiring should be taken into account.

The advantage of a flexible cable is that it is much simpler. stow, cable channelas well as directly in the junction box or shield. But during the installation of electrical wiring, in particular when connecting a flexible cable in the switchboard to protective devices and terminal blocks, to the switches, sockets and lighting devices, it is necessary to terminate the cable cores.

The termination of the cores of the flexible cable is carried out by special crimp lugs or by soldering them. Accordingly, when choosing a flexible cable for wiring, it is necessary to spend additional time on cable termination and funds on the acquisition of crimp lugs, crimp tools. In addition, a flexible cable is much more expensive than a hard cable.

A single-core cable in this case has an advantage, since its conductors are connected to the above wiring elements immediately after removing the insulating layer, without additional preparation (crimping with lugs, soldering), and when connecting in junction boxes, a multi-core cable is much easier to weld or crimp with sleeves.

One of the advantages of a flexible cable in home wiring is fracture resistance with frequent reconnection of the wire when replacing sockets, a switch or a lamp. But, subject to the selection of reliable sockets, switches, fixtures, the correct selection of protective devices, as well as subject to the rules for the operation of electrical wiring, a hard cable lasts quite a long time, since reconnecting the cable and, accordingly, bending it is rather rare.

Flexible and rigid cable in electrical installations

In electrical installations of distribution substations, industrial enterprises, a rigid cable is used to connect stationary equipment, auxiliary circuits for various purposes.Flexible cable in electrical installations is mainly used when connecting circuits inside switchboards for various purposes, in relay protection cabinets and automation equipment of substations. A hard cable can also be selected for this purpose.

In this case, it all depends on the design of the connected element. For example, in relay protection and automation cabinets, a flexible wire is used to connect secondary circuits to microprocessor protection terminals, since connecting a hard cable can damage the terminals of the device.

The flexible cable in the workshops of the enterprise is used to connect mobile power tools, welding machines and other electrical equipment that does not have a fixed location. Also, a flexible cable is used to power individual moving units that are available in the design of a particular item of equipment, for example, in a machine.

A rigid, single-core cable has a limited bending radius, so if you need to lay the cable at an angle close to a straight line, you prefer a flexible cable that can bend at a small radius.

It should be noted that the flexibility of the cable may be different. There are seven classes of cable flexibility. The higher the class, the higher the cable flexibility: the first class of flexibility corresponds to a single-core cable, the seventh class corresponds to the most flexible. As for the cost of the cable, the higher its flexibility class, the more expensive it is.

See also at bgv.electricianexp.com:

Marking electrical wires and cables

The practice of wiring and connecting a TV cable in an apartment - features of the process

Which wires and cables are best used in home wiring

How to install and connect an additional outlet to the wiring

Protection of wires and cables from rodents

Comments:

# 1 wrote: | [quote]

I liked the article. But something is not written about the current throughput. They say that with the same quadrature, a larger current can be passed through a flexible cable than through a single-core cable. Is it so? Could you write about this in the next newsletter?

Comments:

# 2 wrote: Michael | [quote]

I heard about the topic with high bandwidth, they explain that a multicore cable has a larger surface area (if we summarize the surface areas of all the veins included in it), and electric current flows precisely over the surface of the conductor.

Comments:

# 3 wrote: | [quote]

A wire happens with a single-wire-mono-core and multi-wire core erroneously considered as a multi-core. The more wires in the vein, the softer the vein. The current flows along the surface of the wire; therefore, a multi-wire core with the same cross section is more resistant to overloads.

Comments:

# 4 wrote: | [quote]

The current flows along the surface of the wire in high-frequency installations with a frequency in Megahertz. And at a frequency of 50 Hz, current flows over the entire area.

Comments:

# 5 wrote: Michael | [quote]

Firstly: A cable is called multi-wire, and a multi-core cable is one with many wires.
Secondly: Application and definition are standardized by GOST GOST
15845-80

There are ALL GOSTs. EVERYTHING is spelled out before us, you don’t need to invent anything. Internal wiring is carried out by installation wires (monolithic). Wiring for mobile el. devices are performed el. cords (multiwire), including for spotlights (spotlights).

Comments:

# 6 wrote: | [quote]

Correct the article, the article contradicts the TNLA!

Comments:

# 7 wrote: MaksimovM | [quote]

Vladislav, yes, indeed, for the same cross section, a cable with flexible conductors passes a greater current than with monolithic conductors. But the difference in current is negligible. For example, a hard cable with a cross section of 2.5 square meters. mm is designed for a rated current of 27 A, and a flexible cable of the same cross section is just over 30 A.Therefore, usually the reference data give the permissible loads of cable and wire products, regardless of the core design. Much also depends on the reliability of the termination and connection of the flexible cable cores.

Michael, GOSTs, PUE and other regulatory documents spell out almost all issues relating to electrical engineering, energy. If you talk like that, then why create sites, forums, discuss issues?

According to the rules, internal electrical wiring is performed by monolithic wires. But also the rules do not prohibit wiring with a flexible wire, because there are situations when a hard cable cannot be used. The article also describes in which cases to give preference to flexible, and in which rigid cable.

Often in practice it is impossible to do everything strictly according to the rules and recommendations of regulatory documents. Sometimes you need to bend the cable under a small radius. If you bend the hard cable under a radius less than the permissible, then in places of such bends there is a high probability of damage to the cable during its operation. Therefore, in this case, you only need to select a flexible cable. The same goes for bending resistance as well as softness of cores. Cable is always chosen according to local conditions.

Comments:

# 8 wrote: | [quote]

Place a picture of a multi-wire cable for comparison with a single-wire cable. And then two pictures of the same type of cable, a non-initiate can get confused.

Comments:

# 9 wrote: Yuri | [quote]

As correctly noted, flexible cables are MULTI-WIRE, rather than stranded. For example, the PV-3 wire is single-core, but nonetheless flexible, unlike PV-1, which is also single-core and not flexible)))
It is also worth noting that flexible cables (mainly of small cross-sections, and (or) having a large number of wires in the core) are made, as a rule, of higher quality copper. The thinner each wire is, the better copper should be, because it will not stretch in the manufacture of the wire itself.
Then, as a single-wire core, many manufacturers made anything horrible, it happened that such copper was magnetic)))

Comments:

# 10 wrote: Victor | [quote]

And multi-wire copper is far from ice. Either strews when stripping insulation, or as hard as a motorcycle cable.