During the creation of power cable networks for various purposes there is always a problem of obtaining a permanent connection of the individual cable segments.
This procedure is most often done:
- splices in cables, the individual segments in those situations where there is a need to form lines of desired length;
- when the branches and the branch line;
- the so-called rough cut of the cable system and the rapid restoration of the wiring operation in emergency situations.
A compound in such situations may be performed in various ways. For example, you can okontsevat spliced cables releasable connector elements, and after installation, simply insert the plug into the socket.
It is acceptable to apply to special PPE-through terminals or equivalent. These solutions are expensive, require a certain skill in their use. In certain situations, you can do a simple means, including twisting wires.
Pros and cons of a twist connection
The main advantage of twisting as the connection method is reasonably considered:
- simplicity and high speed producing the compound;
- there is no need for special tools;
- minimum amount required consumables.
The list of the main drawbacks include:
- unacceptability use in high power networks (due to the risk of fire can not be connected through twist doge electric kettles, heaters, household and other similar device with a power of 1 kW and higher);
- presence of a particular implementation of skill;
- the need for careful additional insulation for cable connections.
Additionally, we point out that you can only connect twisting wires of the same material.
PUE prohibits the use of this type of connection without the use of additional measures to increase reliability. However, if certain simple rules it is admissible in the organization of temporary connections.
The reasons for poor connections twisting and ways to combat them
Technical shortcomings twist - a direct consequence of high risks of obtaining a large contact resistance with its uncontrolled increase over time. This is determined by the appearance of the oxide film, supplemented moving wire by mechanical action on the spliced cables.
Techniques to eliminate these disadvantages are based on eliminating the root causes. Since the rate of formation of the oxide film with its high resistivity is reduced using hermetically. The increase of resistance due to reduction of the contact area is suppressed when moving wires tightly pressed to each other.
Splicing single-wire veins
Splicing process comprises:
- removing the insulation at a length up to 5 cm (twist long lengths easier to lay, and the excess can be cut);
- neat sweep lived to a mirror finish;
- laying the wires parallel to each other and to perform one or two turns of the fingers;
- full twisting (pliers can be made);
- tousles free end side cutter is removed.
The result is to obtain the compound neat as a two or multiple conductors. Figure 1 demonstrates the latter
Curl should only exposed part of the veins, isolated areas are left without twisting. The direction of rotation was living does not matter.
Acceptable leaving one conductor straight and the other to wind it as that shown in Figure 2.
To increase the reliability of recommended to perform at least six turns, and solder the contact area, Figure 3.
Ready to protect the splice tape, heat shrinkable sleeve or different caps Figure 4.
Features stranded Stranding
This compound is made by the same rules, and differs mainly in that for increasing the area contact of individual wires are formed three-five (sometimes more) identical volume braids as shown in Figure 5.
Then, these braids are used as the basic elements of a mating twist pigtails of the second cable. Then the resulting braids can be woven with one another and compress further.