Views:136 Author:Site Editor Publish Time: 2021-01-27 Origin:Site
Due to the different types of wires and connection forms, the connection methods are also different. Commonly used connection methods are twisted connection, compression connection, welding, and so on. Before connection, carefully peel off the insulation layer at the connection part of the wire, taking care not to damage the core wire.
Wire strippers or wire cutters can be used to strip the insulation layer of the wire, or an electrician's knife can be used to cut the insulation layer of the plastic hard wire. When cutting the plastic hard wire insulation layer with an electrician's knife, the electrician's knife-edge forms an angle of 45° with the wire on the wire to be cut. Cut into the insulating layer obliquely, and then push it at a 25° angle. Finally, fold the cut insulation layer and cut it all at once. Do not cut the core when cutting the insulation.
Twisted connection refers to directly twisting the core wires of the wires to be connected tightly. Copper wires are often connected by twisting.
1) Straight-line connection of single copper core wire
(1) The connection method of small cross-section single-strand copper wire is shown in Figure 1. First, cut the two wire ends into a certain length of wire core to remove the oxide layer on the surface of the wire core. Cross the two-wire cores in an X shape and twist them for 2 to 3 turns, then pull the straight end. Then tightly wind each thread end on the other core wire for 5-6 turns, cut off the remaining thread end, and clamp the end of the thread end.
(2) The connection method of large cross-section single-strand copper wire is shown in Figure 2. First, insert a core wire of the same diameter at the overlap of the core wires of the two wires. Then use a bare copper wire with a cross-section of about 1.5mm2 to tightly wind it. The winding length is about 10 times the diameter of the wire. Then fold back the core wires of the connected wires. After winding the bare copper wires at both ends for 5-6 turns, cut off the excess thread.
(3) The connection method of single-strand copper wires with different cross-sections is shown in Figure 3. First, wrap the core wire of the thin wire tightly around the core wire of the thick wire for 5-6 turns. Then fold back the end of the thick wire core wire and press it tightly on the winding layer. After winding the thin wire core wire for 3 to 4 turns, cut off the excess thread.
2) Branch connection of single copper wire
(1) The T-branch connection of a single-strand copper wire is shown in Figure 4. Wrap the end of the branch core wire tightly around the main core wire for 5 to 8 turns, then cut off the excess wire end. For core wires with smaller cross-sections, first, tie the end of the branch core wire to the main core wire with a loop knot, then tightly wind it for 5 to 8 turns, and cut off the excess wire end.
(2) The cross branch connection of single-strand copper wire is shown in Figure 5. Wrap the thread ends of the upper and lower branch core wires tightly around the main core wire for 5 to 8 turns, then cut off the excess thread ends. You can wind the ends of the upper and lower branch core wires in one direction [see Figure 5(a)], or in both directions [see Figure 5(b)].
3) Direct connection of multiple copper wires
The direct connection of multiple copper wires is shown in Figure 6. First, straighten the multi-strand core wire from which the insulation layer is stripped, twist about 1/3 of the core wire close to the insulation layer and tighten it, and spread the remaining 2/3 core wire into an umbrella shape. The same goes for the other core wire to be connected. Next, after inserting the two umbrella-shaped core wires facing each other, pinch the core wires flat. Then divide the core wire ends of each side into 3 groups, and first lift the first set of wire ends on one side and wrap them tightly on the core wire. Then lift the head of the second group and wrap it tightly on the core wire. Finally, the third group of thread ends is turned up and tightly wound on the core wire. Wind the end of the thread on the other side in the same way.
4) Branch connection of multiple copper wires
There are two ways to connect the T-branch of multiple copper wires.
(1) One method is shown in Figure 7. After the branch core wire is bent 90°, it is parallel to the trunk core wire [see Figure 7(a)]. Then fold back the end of the thread and wrap it tightly on the core wire [see Figure 7(b)].
(2) Another method is shown in Figure 8. Twist and tighten about 1/8 of the branch core wire close to the insulation layer, and divide the remaining 7/8 core wires into two groups [see Figure 8(a)]. One set is inserted into the core wire of the main road, and the other set is placed in front of the core wire of the main road, and wind 4 to 5 turns to the right in the direction shown in Figure 8(b). Then wind the group inserted into the core wire of the main road to the left in the direction shown in Figure 8(c) for 4 to 5 turns. The connected wires are shown in Figure 8(d).
5) Connection of single-strand copper wire and multi-strand copper wire
The connection method of the single-strand copper wire and the multi-strand copper wire is shown in Figure 9. First, twist and tighten the core wires of the multi-strand wire into a single strand. Then wrap it tightly on the core wire of the single-strand wire for 5 to 8 turns. Finally, fold back the end of the single-strand core wire and press it tightly on the winding part.
6) Connection of wires in the same direction
When the wires to be connected come from the same direction, the method shown in Figure 10 can be used.
For single-strand wires, the core wire of one wire can be tightly wound on the core wires of other wires. Fold back the end of the other core wires and press tightly.
For multi-strand wires, the core wires of the two wires can be crossed and then twisted and tightened.
For the connection of a single-strand wire and a multi-strand wire, the core wire of the multi-strand wire can be tightly wound on the core wire of the single-strand wire, and then the end of the single-strand core wire can be folded back and pressed tightly.
7) Connection of two-core or multi-core wire and cable
When connecting two-core sheathed wire, three-core sheathed wire or cable, or multi-core cable, care should be taken to stagger the connection points of each core wire as much as possible to better prevent leakage or short circuit between wires. Figure 11 (a) shows the connection of the double-core sheathed wire. Figure 11(b) shows the connection of the three-core sheathed wire. Figure 11(c) shows the connection of the four-core power cable.
Connection of 19 strands of copper core wires. Because of the large number of core strands, when connecting in a straight line, the middle of the core can be clamped. After the wire is connected, in order to increase its mechanical strength and improve its conductivity, it should be soldered.
The method of soldering the copper core wire connection is:
First, put the solder in a tin pot to melt it at a high temperature, then place the wire connector with clean surface treatment on the tin pot, and pour the molten tin on the joint with a spoon. In the beginning, due to the low temperature at the joint, the joint is not easy to be tinned. Continue to pour tin to increase the temperature of the joint and dip the tin until the joint is completely welded. Finally, remove the surface welding slag to make the surface of the joint smooth.
Connection of aluminum core wire. Because aluminum wires are easy to oxidize and the resistivity of the oxide film is high, copper wires should not be used for aluminum core wires. Aluminum core wires should be crimped by bolts and crimped tubes.
The bolt crimping method is suitable for the connection of aluminum core wires with small loads. The crimping pipe crimping method is suitable for the connection of the multi-stranded aluminum conductor with a larger load (also suitable for the copper conductor). When crimping, select the appropriate aluminum crimping tube according to the specifications of the aluminum core wire. Clean the crimping area first, and thread the two aluminum core wires into the crimping tube. Extend the two wire ends about 30mm from the crimping tube, and then crimp them with crimping pliers. When crimping, the first pressure pit should be pressed on the side of the aluminum core end. The crimping quality should meet the technical requirements.
The insulation layer of the wire is damaged due to external factors, or the wire is connected to ensure the safe use of electricity, its insulation must be restored. The insulation strength after the restoration of insulation shall not be lower than that of the original insulation layer. Commonly used insulating materials include butter tape, polyester film tape, and black tape. When doing insulation restoration, the starting point of the insulation tape should be twice the distance of the insulation bandwidth from the core. When wrapping, the yellow wax tape and the wire should maintain a certain inclination, that is, 1/2 of the pressure band per turn. After wrapping the first layer of yellow wax tape, connect the end of the yellow wax tape with black tape and wrap a layer in the opposite direction. The method is the same as before to ensure the insulation performance after the insulation layer is restored.
1. The tightening force should be moderate to prevent the bolts and nuts from slipping with too much force. It is found that the bolts and nuts that have been buckled are replaced in time, and it is strictly prohibited to work.
2. When using a screwdriver to tighten or loosen the screw, the screwdriver must be used to tighten the screw, and then tighten or loosen it. Prevent the screwdriver and the screw from slipping, causing damage to the screw, which is not easy to disassemble, especially the common air switch of the hanging box.
3. If you find bolts and nuts that are difficult to disassemble, do not act recklessly to prevent deformation and make it more difficult to disassemble. Appropriate knock, or screw loosening agent, dilute hydrochloric acid, etc. should be given, and the disassembly will be performed later.
4. Do not use pliers to fasten or loosen bolts and nuts to prevent damage. When using a live-end wrench, adjust the opening to prevent the bolts and nuts from being damaged and deformed, making it difficult to disassemble and assemble.
5. The same terminal block allows up to two wires of the same type and specification.
6. For wiring terminal blocks that are easy to loose or have poor contact, the wire connectors must be fastened to the wiring terminals in a "?" shape which is to increase the contact area and to prevent loosening.
7. It is strictly forbidden to install non-copper gaskets or non-conductive gaskets in the middle of wire connectors or wire noses.
8. When connecting wire connectors, the contact surface must be smooth and free from oxidation. When the wiring lugs or copper bars are connected, after the contact surface is cleaned, apply the conductive paste, and then tighten.
9. When connecting temporary wires, if a single wire is flexible, it is required to fold the terminal in half and then connect it to the lower port of the air switch. The single-core hard wire should be connected to the lower port of the air switch in a "?" shape.
10. For motor wiring of 30KW and above, it is required that no gaskets with poor conductivity, such as galvanized nuts, flat gaskets, spring gaskets, etc., should be connected between the motor outlet and the cable conductors connecting the motor.
11. When using insulating tape to wrap cables or other equipment to protect insulation, the insulating layer should be wound from one end to the other in a ratio of 1/2 of the pressure, and at least one back and forth.