Braided Forissier Braided Copper Strip Selection Guide

2.3 Derating factor for parallel use

When multiple braided connectors are used in parallel for the same phase, the total current carrying capacity is not simply superimposed due to uneven current distribution. The following parallel coefficient correction is required:

Quantity coefficient of parallel connectors

1 1.0

2 1.83

3 2.54

4 3.25

5 3.96

6 4.48

7 5.5

8 6.5

Calculation method:

Determine the number of connectors n that need to be connected in parallel.

The current carrying capacity of a single connector is I2 single (refer to the table based on the cross-section and ambient temperature).

The actual total current carrying capacity of this combination is equal to I2 single multiplied by the parallel coefficient.

To achieve the target current Itotal, the required single current carrying capacity is I2 single ≥ Itotal/coefficient, and then the cross-section is reverse checked.

Case: The environment is 35 ° C and requires a total current of 1500 A. It is planned to use 4 parallel connections. If the coefficient of 4 is 3.25, then each one needs to provide 1500/3.25 ≈ 462 A. According to the table, bare copper at 35 ° C: 250 mm ² is 516 A, which meets the requirements. Therefore, four 250 mm ² bare copper braided tapes are selected in parallel.

Guidelines for Terminal Drilling Specifications and Selection

3.1 Standard drilling types

Forissier offers three standard drilling types (Type I, II, III) to accommodate different device wiring terminals:

Type I: Single hole centered, suitable for small and medium-sized sections (60-75 mm ²), with A × B sizes of 30 × 30 or 40 × 40 mm.

Type II: Double hole, suitable for 100-400 mm ², specific dimensions are shown in the table below.

Type III: Four hole, suitable for large cross-sections (400~2000 mm ²).

3.2 Recommended terminal dimensions and drilling layout for each section

Sectional area (mm ²) Terminal length A (mm) Width B (mm) Hole spacing C (mm) Hole edge distance D (mm) Recommended drilling type

60-75 30 or 40-- I

100 - 120 80 40 40 - II

150 - 200 80 - 100 50 40 - II

250 - 300 100 60 50 40 II/III

400 - 800 100 - 120 60 - 80 40 - 50 40 - 50 III

1000 - 1200 120 - 160 60 - 100 60 50 III

1600 - 2000 160 - 200 60 - 70 60 - 70 60 III

Key dimension description:

A: Terminal length (along the direction of the braided tape)

B: Terminal width (perpendicular to the braided tape)

C: Center distance between two holes (Type II/III)

D: The distance from the center of the outermost hole to the edge of the terminal

Hole diameter ∅: standard 10-18mm, can be customized according to needs

Selection suggestion:

For medium voltage circuit breakers or switchgear, type II or III drilling is usually selected to match the equipment terminal block.

If the device terminal is a screw structure, flat terminals without drilling holes can be used (crimping or welding should be provided).

3.3 Special Processing

Angle forming: It can produce terminals with angles (such as 30 ° or 45 °), suitable for installation with limited space.

Mechanical reinforcement: For ultra long or large cross-section connectors, mechanical reinforcement extra flexible can be added to prevent sagging or vibration fatigue.

Surface treatment: In harsh environments such as humidity, salt spray, and corrosive gases, it is recommended to use 15 μ m tin plating or silver plating.

Installation and usage precautions

4.1 Optimal installation direction

Forissier strongly recommends installing the braided connector vertically (i.e. with the braided tape in the vertical direction). This can:

Avoid long-term bending deformation caused by gravity;

Beneficial for air convection and heat dissipation, reducing temperature rise;

Reduce the accumulation of dust and moisture.

If horizontal installation is unavoidable, ensure that the connectors have sufficient support or use reinforced types.

4.2 Spacing during Parallel Connection

When multiple braided tapes are connected in parallel in the same phase, the minimum spacing between connectors should not be less than the thickness of a single connector. A too small spacing can lead to increased mutual inductance effect, uneven current distribution, and increased heat dissipation difficulty.

4.3 Avoid copper wire damage

The flaring design of the terminal has reduced the risk of copper wire being crushed, but it is still necessary to avoid excessive bending or torque transmission to the braided tape during installation.

Use a torque wrench to tighten the bolts according to the required torque of the equipment. Tightening too tightly may fracture the copper terminal tube, while loosening too loosely may increase the contact resistance.

4.4 Temperature Monitoring

In practical operation, it is recommended to monitor the temperature of the hottest point of the connector through infrared temperature measurement or surface mount thermocouple. The surface temperature of bare copper connectors should not exceed 85 ° C, and tinned connectors should not exceed 105 ° C. If it exceeds, consideration should be given to:

Increase the cross-section or increase the number of parallel connections;

Reduce environmental temperature (improve ventilation);

Check for harmonic currents causing additional heating.