Braided Forissier Braided Copper Strip Selection Guide

Braided Forissier Braided Copper Strip Selection Guide

In high current power equipment, hard busbar connections often experience mechanical stress due to thermal expansion, contraction, vibration, or installation tolerances, leading to poor contact and even equipment damage. Braided flexible connections are the key components to solve this problem. Forissier Company (TRESSE METALLIQUE J. FORISSIER), as a brand under the International Wire Group, offers copper braided tapes with standardized cross-sections ranging from 60mm ² to 2000mm ², which are widely used in medium voltage switchgear, circuit breakers, transformers, industrial furnaces, and electrolytic cells.

This article is aimed at electrical design engineers and on-site maintenance personnel, systematically introducing the technical characteristics, selection criteria, parallel use rules, terminal processing requirements, and installation precautions of Forissier braided connectors, helping you make the optimal choice under different environmental temperatures and current carrying requirements.

Product Structure and Technical Advantages

1.1 Weaving tape material and process

Forissier's flexible connectors use flat or circular braided copper strips, with copper wire diameters of 0.10 mm (fine wire) or 0.20 mm (standard wire) available, and can provide 0.30 mm as needed. Fine wire braiding provides better flexibility and is suitable for high vibration or frequent displacement situations; Standard silk provides higher mechanical strength.

Copper wire material: Cu ETP (electrolytic tough copper) that complies with NF EN 13602 (formerly NFC 31 111) standard, with a copper content of ≥ 99.9%, a 20 ° C resistivity of ≤ 0.017241 Ω· mm ²/m (100% IACS), and a mechanical strength of ≥ 200 MPa in annealed state.

Connection terminal: formed by crimping or brazing bare copper tubes, with a wall thickness of 2 mm and standard lengths of 50, 80, 100, and 120 mm. The terminal surface can be tin plated (5 μ m conventional, 15 μ m harsh environment), silver plated (5/10 μ m), nickel plated, or gold plated.

Brazing process: Dip brazing can be used between copper pipes and braided tapes to effectively reduce contact resistance, prevent capillary water absorption, prevent external corrosion from spreading to the inside of the connection, and significantly extend the service life.

1.2 Main advantages

TMF solution: Customize weaving types and terminal angles (such as angled terminals) according to customer needs for easy installation.

Low contact resistance: The brazing process reduces heat generation and improves current carrying capacity.

Anti electric force damage: The copper tube is flaring treated on the braided belt side to prevent the copper wire from being cut or worn under the action of electric force.

Long lifespan: Both mechanical and electrical characteristics are guaranteed, reducing maintenance frequency.

Current carrying capacity and selection table

2.1 Rated current conditions

The data table provided by Forissier provides the maximum continuous current (I Max) allowed for a single connector at stable ambient temperatures (25 ° C, 35 ° C, 45 ° C). The limiting condition is the final temperature of the conductor:

Bare copper or red copper connector: ≤ 85 ° C

Tin plated copper connector: ≤ 105 ° C

The values in the table are based on the following assumptions:

Only a single connector works, without adjacent heat sources;

Stable ambient temperature;

Vertical installation of connectors (recommended).

2.2 Comparison of standard cross-section and current carrying capacity

The following are the current carrying capacities of some typical sections (unit: A), organized according to the original table:

Sectional area (mm ²) Terminal width (mm) Bare copper/red copper - Environment 25 ° C Bare copper -35 ° C Bare copper -45 ° C Tin plating -25 ° C Tin plating -35 ° C Tin plating -45 ° C

60 30/40 351 317 280 389 359 326

75 30/40 389 351 317 426 393 358

100 40/50 426 393 358 440 405 369

120 (2×60) 40/50 440 405 369 480 442 403

150 40/50 480 442 403 505 456 403

200 40/50 505 456 403 560 516 470

250 50/60 560 516 470 602 554 505

300 (2×150) 50/60 542 490 433 619 571 539

400 (2×200) 60/80 619 571 539 663 611 556

500 (2×250) 60/100 663 611 556 701 646 588

600 (3×200) 60/80 747 689 627 826 761 693

800 (4×200) 80/100 826 761 693 991 913 832

1000 (4×250) 80/100 991 913 832 1153 1063 967

1200 (6×200) 100/120 1153 1063 967 1356 1250 1137

1600 (8×200) 120/160 1356 1250 1137 1468 1353 1232

2000 (8×250) 160/200 1468 1353 1232 1775 1636 1490

Selection example:

The ambient temperature is 35 ° C, and a current carrying capacity of 600 A is required. Bare copper connectors are selected: according to the table, 150 mm ² (505A) is insufficient, and 200 mm ² (560A) is still insufficient. 250 mm ² (602A) or 300 mm ² (619A) are needed. Alternatively, tin plating of 200 mm ² (560A is still insufficient) can be used, and ultimately tin plating of 250 mm ² (619A) or two 150 mm ² parallel wires can be chosen.

Note: The values in the above table are for a single connector, and when multiple connectors are connected in parallel, they need to be multiplied by the parallel factor.