Stranded connection refers to directly and tightly twisting the core wires of the conductors to be connected together. Stranded connections are commonly used for copper conductors. Although aluminum conductors can also be stranded, the surface of the aluminum core wire is extremely prone to oxidation, which will cause circuit faults over time. Therefore, aluminum conductors are usually connected using a compression joint.
Direct connection of single-strand copper conductors. The connection method for small-section single-strand copper conductors is shown in Figure 1. First, cross the ends of the two conductor core wires in an X-shape, then wrap them together 2-3 times, straighten the ends, and then tightly wrap each end around the other core wire 5-6 times before cutting off the excess. The connection method for large-section single-strand copper conductors is shown in Figure 2. First, insert a core wire of the same diameter at the overlap of the two conductor core wires, then tightly wrap a bare copper wire with a cross-section of approximately 1.5 mm² around it, with a wrapping length about 10 times the conductor diameter. Then, fold the ends of the conductors to be connected back, and then continue wrapping the bare copper wire at both ends 5-6 times before cutting off the excess.
The connection method for single-strand copper wires with different cross-sections is shown in Figure 3. First, tightly wrap the core of the thinner wire around the core of the thicker wire 5-6 times. Then, fold the end of the thicker wire back and press it tightly onto the wrapped layer. Continue to wrap the thinner wire around it 3-4 times, and then cut off the excess wire.
Branch connection of single-strand copper wire. The T-branch connection of single-strand copper wire is shown in Figure 4. Tightly wrap the end of the branch wire around the main wire 5-8 times, and then cut off the excess wire. For core wires with smaller cross-sections, first tie a loop knot on the main wire with the end of the branch wire, then tightly wrap it 5-8 times, and then cut off the excess wire.
Cross branch connection of single-strand copper wire is shown in Figure 5. Tightly wrap the ends of the upper and lower branch wires around the main wire 5-8 times, and then cut off the excess wire.
The ends of the upper and lower branch core wires can be wound in one direction [see Figure 5(a)], or wound in both left and right directions [see Figure 5(b)].Direct connection of multi-strand copper wires. The direct connection of multi-strand copper wires is shown in Figure 6. First, straighten the multi-strand core wires after stripping the insulation layer, twist and tighten about 1/3 of the core wires closest to the insulation layer, and spread the remaining 2/3 of the core wires out in an umbrella shape. Treat the other core wire to be connected in the same way. Next, insert the two umbrella-shaped core wires towards each other and flatten them. Then, divide the ends of the core wires on each side into 3 groups. First, lift the first group of ends on one side and tightly wrap it around the core wire. Then, lift the second group of ends and tightly wrap it around the core wire. Finally, lift the third group of ends and tightly wrap it around the core wire. Wrap the ends of the other side in the same way.
Branch connection of multi-strand copper wires. There are two methods for connecting T-shaped branches of multi-strand copper wires. One method, as shown in Figure 7, involves bending the branch core wire 90° parallel to the main core wire [see Figure 7(a)], then folding the end back and tightly wrapping it around the core wire. The other method, as shown in Figure 8, involves twisting and tightening about 1/8 of the branch core wire closest to the insulation layer, and dividing the remaining 7/8 core wire into two groups [see Figure 8(a)]. One group is inserted into the main core wire, and the other group is placed in front of the main core wire and wrapped 4-5 times to the right as shown in Figure 8(b). Then, the group inserted into the main core wire is wrapped 4-5 times to the left as shown in Figure 8(c). The connected wire is shown in Figure 8(d). Connecting single-strand copper wires with multi-strand copper wires. The connection method between single-strand copper wires and multi-strand copper wires is shown in Figure 9. First, twist and tighten the core wires of the multi-strand wire into a single strand. Then, tightly wrap the multi-strand wire around the core wire of the single-strand wire 5-8 times. Finally, fold the end of the single-strand wire back and press it firmly against the wrapped area.
Connecting 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, tightly wrap the core wire of one wire around the core wire of another wire, and then fold the end of the other wire back and press it firmly. For multi-strand wires, cross the core wires of the two wires and then twist and tighten them. For connecting single-strand and multi-strand wires, tightly wrap the core wire of the multi-strand wire around the core wire of the single-strand wire, and then fold the end of the single-strand wire back and press it firmly.
Connecting two-core or multi-core wires and cables.
When connecting two-core sheathed wires, three-core sheathed wires or cables, or multi-core cables, care should be taken to stagger the connection points of each core as much as possible to better prevent leakage or short circuits between wires. Figure 11(a) shows the connection of a two-core sheathed wire, Figure 11(b) shows the connection of a three-core sheathed wire, and Figure 11(c) shows the connection of a four-core power cable.