Copper Stranded Wire (Cu)

Copper Stranded Wire

Copper stranded wire is a composite wire made by twisting multiple thin copper wires according to specific rules using a high-speed twisting machine or a single twisting machine. It combines the high conductivity of a single copper wire with the flexibility and tensile strength of the twisting structure, and is the core material for power transmission, electrical connection, and special scenario applications.

Core Features

Conductivity: Copper's conductivity is second only to silver, with a large total cross-sectional area and high current carrying capacity after twisting.
Flexibility: Multi strand twisting disperses stress and has better resistance to bending fatigue than single strand copper wire.
Tensile strength: The twisted structure enhances mechanical strength, and the tensile strength of hard copper stranded wire can reach 350-500 MPa.
Corrosion resistance: Can be tin plated, silver plated, or coated with insulation layer to meet different environmental requirements.

Manufacturing Process

The production process of copper stranded wire includes drawing, annealing, stranding, testing. Specifically, as follows:
Copper Rod Pretreatment
Electrolytic copper (purity ≥ 99.99%) is continuously cast and rolled to produce copper rods with a diameter of 8mm.
Wire Drawing
Multi pass drawing (with the mold aperture gradually decreasing), pull the copper rod to the target diameter (0.1-4mm).
Lubricants (saponification solution or vegetable oil) reduce friction and prevent copper wire surface oxidation.
Annealing
Soft stranded wire needs to be annealed in a protective atmosphere (nitrogen) (400~600 ° C) to eliminate work hardening.
Hard twisted wire skips annealing and retains cold tensile strength.
Stranding
Multiple single wires twisted in the same direction, with a pitch ratio (twist distance/twist diameter) of 8-14, used for small section wires.
Detection
Electrical resistivity: detected by four terminal method.
Cross sectional area: weighing method or laser caliper.
Stranded tightness: Bending test (with no loose strands around the axis diameter ≤ 10 times the wire diameter).

Copper Stranded Wire List

Sectional Area (Standard, mm2)	Sectional Area (Calculated, mm2)	Strands	Struture	Outer Diameter (mm)
0.03	0.03	13	13/0.05	0.22
0.04	0.04	10	10/0.07	0.27
0.06	0.06	16	16/0.07	0.34
0.10	0.10	26	26/0.07	0.42
0.16	0.16	41	41/0.07	0.52
0.25	0.25	65	65/0.07	0.65
0.30	0.30	77	7×11/0.07	0.84
0.40	0.40	105	7×15/0.07	0.97
0.50	0.51	133	7×19/0.07	1.05
0.63	0.62	161	7×23/0.07	1.18
0.75	0.75	196	7×28/0.07	1.28
1.00	0.997	259	7×37/0.07	1.47
1.60	1.57	408	12×34/0.07	1.97
2.50	2.49	646	19×34/0.07	2.35
4.00	4.03	513	19×27/0.10	3.08
6.30	6.27	798	19×42/0.10	3.73
10.00	10.00	1273	19×67/0.10	4.73
16.00	15.83	2016	12×7×24/0.10	7.18
25.00	25.07	3192	19×7×24/0.10	8.55
(35)	34.47	4389	19×7×33/0.10	9.90
40.00	39.96	2261	19×7×17/0.15	11.03
(50)	49.36	2793	19×7×21/0.15	12.15
63.00	63.46	3591	19×7×27/0.15	13.50
(70)	70.51	3990	19×7×30/0.15	14.18
80.00	79.91	4522	19×7×34/0.15	15.08
(95)	94.01	5320	19×7×40/0.15	16.43
100.00	100.73	5700	19×12x25/0.15	18.27
(120)	120.87	6840	19×12×30/0.15	20.24
125.00	127.59	7220	19×19×20/0.15	20.29
160.00	159.42	9025	19×19×25/0.15	21.75
(185)	185.00	10469	19×19×29/0.15	23.25
200.00	196.15	11100	37×12×25/0.15	25.58
250.00	251.08	14208	37×12×32/0.15	28.67
315.00	310.58	17575	37×19×25/0.15	30.45
400.00	397.54	22496	37×19×32/0.15	34.13
500.00	496.92	28120	37×19×40/0.15	38.06

Copper Stranded Wire Application

Copper stranded wire has the advantages of good flexibility, strong resistance to bending fatigue, large cross-sectional area, high current carrying capacity, lower cost than solid copper bars, and easy installation. It is mainly used in the following situations:
Power System
Overhead transmission line: Copper core enhanced conductivity in JL/G1A-400/50 steel cored aluminum stranded wire.
Transformer winding: Swap wires (cross-sectional area ≥ 500mm ²) to reduce eddy current losses.
Construction Work
Lightning protection grounding system: Tin plated copper stranded wire (cross-sectional area 25~120mm ²) is used as the down conductor.
Electromagnetic shielding mesh: thin copper stranded wire braided layer suppresses high-frequency interference.
Transportation
Rail transit contact network: Copper magnesium alloy stranded wire is wear-resistant.
Automotive wiring harness: ultra flexible stranded wire (cross-sectional area 0.5~6mm ²) is suitable for engine compartment vibration.
New Energy and Industry
Photovoltaic power station: Tin plated copper stranded wire connected to solar panels, resistant to outdoor corrosion.
Welding machine cable: High flexibility twisted wire supports high current output.
Communication Field
RF coaxial cable: Silver plated copper stranded wire serves as the central conductor to reduce signal attenuation.
Base station grounding: Copper stranded wire with a cross-sectional area of 50mm ² ensures lightning leakage.
Special Scene
Deep sea cable: double-layer nickel plated copper stranded wire resistant to seawater corrosion.
Medical equipment: Oxygen free copper stranded wire (OFC) ensures signal transmission purity.