Braided flexible strip
Raw flat braid supplied on reels or in cut lengths for further processing into straps, connectors or flexible busbars.
Flexible conductors & shielding
Braided Aluminium Wire: Flat and Tubular Braid
Braided aluminium wire is made by interlacing many fine aluminium-magnesium filaments into a flat strap or a hollow sleeve. Flat braid is used for flexible earthing straps, jumpers and braided busbars; tubular braid is used as an electromagnetic shield over cables and harnesses. Compared with copper braid it weighs roughly 70 % less for the same metal cross-section, at the cost of lower conductivity, so it suits weight-sensitive vehicles, vessels and energy-storage systems.
- Usual alloy
- 5154 / 5154A Al-Mg
- Filament size
- 0.10 – 0.30 mm (36 – 30 AWG)
- Forms
- Flat strap, tubular sleeve
- Conductivity
- About 32 % IACS
What braided aluminium wire is
A braiding machine winds fine wire filaments from a set of bobbins, called carriers, that travel around each other in opposite directions so the strands pass over and under one another. The result is a hollow, flexible sleeve. Left round, it is a tubular braid for shielding; pressed or woven flat, it becomes a flat braid that behaves like a highly flexible strap.
Braid construction is written as carriers – ends – filament gauge. A "24-5-36" braid, for example, uses 24 carriers, each laying 5 parallel filaments (ends) of 36 AWG wire, so it contains 120 filaments in total. The number and size of filaments set the metallic cross-section, and therefore the current capacity and weight; the braid angle and coverage set the flexibility and shielding performance.
Copper, tinned copper and silver-plated copper are the traditional braid materials. Aluminium braid has grown with vehicle electrification, lightweight aircraft and marine design and the steady pressure on copper prices, because aluminium gives the same flexibility and shielding function at much lower weight.
Why 5154 aluminium-magnesium alloy is used
Pure electrical aluminium such as 1350 conducts best (about 61 – 62 % IACS) but its fine filaments are soft and break easily on braiding machines and in repeated flexing. Most aluminium braid therefore uses 5154 or 5154A, an alloy with roughly 3.1 – 3.9 % magnesium. Magnesium strengthens the filament by solid-solution hardening and improves resistance to salt and humidity, while conductivity falls to about 32 % IACS.
| Property | 5154 Al-Mg braid filament | 1350 electrical aluminium | Annealed copper |
|---|---|---|---|
| Electrical conductivity | ≈ 32 % IACS | ≈ 61 – 62 % IACS | 100 % IACS |
| Resistivity at 20 °C | ≈ 0.054 Ω·mm²/m | ≈ 0.028 Ω·mm²/m | 0.01724 Ω·mm²/m |
| Density | 2.66 g/cm³ | 2.70 g/cm³ | 8.89 g/cm³ |
| Tensile strength | Higher; about 240 MPa annealed, more when drawn hard | Low; fine filaments break easily | About 220 – 250 MPa annealed |
| Corrosion behaviour | Very good, including marine air | Good | Oxidises; usually tinned or plated |
| Main braid use | Shielding, earthing straps, flexible links | High-current braid where strength is less critical | All braid types |
Typical values. Filament tensile strength depends on the drawing and annealing route; ask for test data on the specific lot.
Where conductance matters more than filament strength, some makers braid 1350 or other 1xxx alloys, or use copper-clad aluminium filaments that combine a copper surface for contact and plating with an aluminium core for weight. Each option is a balance between resistance, flex life and termination method.
Flat braided aluminium wire: sizes and data
Flat braid is used wherever a conductor must bend, vibrate or absorb movement: earthing straps across shock mounts, jumpers between battery modules, links across expansion joints in busbar runs and connections to moving switchgear contacts. The table gives representative constructions. Cross-section is calculated from filament count and diameter; mass and DC resistance are calculated for 5154 metal and exclude the few percent extra length that the braid lay adds.
| Nominal width | Construction | Filament | Metal area (mm²) | Metal mass (kg/km) | DC resistance (mΩ/m) |
|---|---|---|---|---|---|
| 3/32 in (≈ 2.4 mm) | 24-2-36 | 0.127 mm (36 AWG) | 0.6 | 1.6 | 88.8 |
| 1/8 in (≈ 3.2 mm) | 24-3-36 | 0.127 mm (36 AWG) | 0.9 | 2.4 | 59.2 |
| 3/16 in (≈ 4.8 mm) | 24-5-36 | 0.127 mm (36 AWG) | 1.5 | 4.0 | 35.5 |
| 1/4 in (≈ 6.4 mm) | 24-10-36 | 0.127 mm (36 AWG) | 3.0 | 8.1 | 17.8 |
| 3/8 in (≈ 9.5 mm) | 24-5-30 | 0.255 mm (30 AWG) | 6.1 | 16.3 | 8.8 |
| 1/2 in (≈ 12.7 mm) | 24-10-30 | 0.255 mm (30 AWG) | 12.3 | 32.6 | 4.4 |
| 3/4 in (≈ 19 mm) | 24-20-30 | 0.255 mm (30 AWG) | 24.5 | 65.2 | 2.2 |
| 1 in (≈ 25 mm) | 24-32-30 | 0.255 mm (30 AWG) | 39.2 | 104.3 | 1.4 |
| 1-1/2 in (≈ 38 mm) | 48-16-30 | 0.255 mm (30 AWG) | 39.2 | 104.3 | 1.4 |
| 2 in (≈ 51 mm) | 48-32-30 | 0.255 mm (30 AWG) | 78.4 | 208.7 | 0.7 |
| 3 in (≈ 76 mm) | 48-47-30 | 0.255 mm (30 AWG) | 115.2 | 306.5 | 0.5 |
Calculated values for guidance only. Measured weight and resistance are slightly higher because of braid lay; confirm on the supplier's data sheet.
Flexible braided busbar
Wide, multi-layer flat braid pressed into a dense strap for high-current paths in battery packs, energy storage and traction equipment.
Braided connectors
Flat braid with crimped or pressure-welded lugs at both ends, linking busbars, motors and switchgear while taking up vibration and misalignment.
Earthing and bonding straps
Narrow braid with punched or crimped terminals for chassis grounding, enclosure bonding and equipotential connections on vehicles and vessels.
Tubular braided aluminium wire for shielding
Tubular braid slides over a cable or wire bundle and is connected to earth at the ends, forming a conductive screen that intercepts electromagnetic interference. Optical coverage, meaning the share of the surface hidden by filaments, is the first quality measure; well-made aluminium braid typically reaches 85 – 90 % or more in normal sizes, with lower values on very small diameters.
| Nominal ID | Construction | Filament | Metal area (mm²) | Nearest AWG by area | Metal mass (kg/km) |
|---|---|---|---|---|---|
| 1/8 in (≈ 3 mm) | 24-5-36 | 0.127 mm | 1.5 | 15–16 | 4.0 |
| 3/16 in (≈ 5 mm) | 24-6-34 | 0.160 mm | 2.9 | 12–13 | 7.7 |
| 1/4 in (≈ 6 mm) | 24-16-36 | 0.127 mm | 4.9 | 10 | 12.9 |
| 1/2 in (≈ 13 mm) | 48-11-36 | 0.127 mm | 6.7 | 9 | 17.8 |
| 5/8 in (≈ 16 mm) | 48-8-34 | 0.160 mm | 7.7 | 8 | 20.5 |
| 7/8 in (≈ 22 mm) | 48-7-30 | 0.255 mm | 17.2 | 5 | 45.6 |
| 1 in (≈ 25 mm) | 48-8-30 | 0.255 mm | 19.6 | 4 | 52.2 |
| 2 in (≈ 51 mm) | 48-14-30 | 0.255 mm | 34.3 | 2 | 91.3 |
The AWG column compares metal area only. Because 5154 conducts about a third as well as copper, an aluminium braid of a given AWG area carries less current than a copper braid of the same size.
- Small ID (up to about 1/4 in): sensor and signal leads, harness branches, control cables
- Medium ID (3/8 – 1/2 in): industrial control cables and main vehicle harness bundles
- Large ID (5/8 – 2 in): power and energy-storage cables, shipboard cables and sleeving over busbars
Aluminium braid compared with copper braid
| Factor | Copper braid (bare or tinned) | 5154 aluminium braid |
|---|---|---|
| Weight, same metal area | Reference | About 70 % lighter |
| Conductivity | 100 % IACS | About 32 % IACS |
| Area for equal resistance | Reference | About 3 times larger, still about 5 % lighter |
| Shielding at equal coverage | Lower transfer impedance, more margin | Adequate for most automotive and industrial EMC needs |
| Flex fatigue | Very good | Good with correct construction and bend radius |
| Corrosion | Bare copper tarnishes; tinned for protection | Self-protecting oxide; good in humid and marine air |
| Termination | Solder, braze, crimp, weld | Crimp, pressure weld or ultrasonic weld; soldering is difficult |
| Joining to copper parts | Direct | Needs bimetallic lugs or washers and moisture sealing |
| Material cost | Higher and more volatile | Lower |
A simple way to decide: if the circuit is limited by voltage drop or heating, or must solder to copper hardware, copper braid is the safe choice. If the goal is weight saving and the design can accommodate a larger cross-section and correct terminations, aluminium braid delivers a lighter assembly. For equal resistance, aluminium alloy braid needs about three times the copper area, which ends up only slightly lighter; for shielding and earthing, where resistance is rarely the limit, the weight saving approaches the full 70 %.
Terminating and installing aluminium braid
Crimped lugs
Use lugs designed for aluminium conductors, filled with contact compound, and crimp tooling qualified for the braid area. Aluminium creeps under constant pressure, so the crimp geometry matters.
Pressure or ultrasonic welding
Consolidating the braid ends into a solid block by pressure or ultrasonic welding removes the gaps between filaments and gives a stable, low-resistance contact face for bolting.
Copper-aluminium joints
Where a braid meets copper busbars or terminals, use bimetallic lugs or copper-aluminium washers and keep the joint dry to prevent galvanic corrosion.
Bolted connections
Use flat washers and spring or conical washers to maintain clamp force, follow the torque value for the hardware size and re-check after thermal cycling where practical.
Bend radius
Keep bends generous and avoid sharp kinks at the lug barrel, where filaments break first under vibration. A strain-relief sleeve helps.
Plating
Tin or silver plating of terminal areas can be specified where a contact surface needs lower and more stable resistance.
Standards and tests for braided conductors
| Standard | Relevance |
|---|---|
| IEC 60228 | Conductor classes for insulated cables, including flexible classes used as a reference for braided conductors |
| ISO 19642 (series) | Road vehicles: automotive cables, including aluminium conductor requirements |
| IEC 62153-4-3 | Measurement of surface transfer impedance, the main test for shield performance |
| ASTM B117 | Neutral salt-spray testing used to compare corrosion resistance |
| ASTM B211 / B800-type wire specifications | Reference specifications for aluminium wire and drawn filaments, depending on alloy |
Useful incoming checks include filament diameter, braid construction count, width or ID, metal area by weight, DC resistance per metre, optical coverage on tubular braid, and the condition of crimped or welded ends on finished connectors.
Typical applications
- Electric and conventional vehicles: flat braid earthing jumpers, engine and body straps, tubular braid over harness bundles
- Battery packs and energy storage: braided flexible busbars between modules, pack grounding and auxiliary links
- Marine and offshore: shielding over shipboard power and control cables, earthing straps in salt air
- Rail and traction: flexible links in panels and across bogie or car-body joints
- Data centres and telecom: bundle-level shielding sleeves and cabinet bonding straps
- Aerospace and defence: lightweight bonding jumpers and shielding where every gram counts
References and standards
- IEC 60228 – Conductors of insulated cables
- ISO 19642 – Road vehicles: Automotive cables
- IEC 62153-4-3 – Metallic cables: surface transfer impedance, triaxial method
- ASTM B117 – Standard Practice for Operating Salt Spray (Fog) Apparatus
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
Braided aluminium (aluminum) wire: frequently asked questions
Is braided aluminium wire as good as copper braid?
For shielding, earthing and flexible links it performs the same function at about 70 % less weight for the same metal area. It conducts about a third as well as copper, so for current-carrying links you need a larger cross-section, and terminations must be designed for aluminium.
Why is 5154 alloy used rather than pure aluminium?
Fine filaments of pure aluminium are weak and break during braiding and flexing. The magnesium in 5154 raises filament strength and corrosion resistance; the trade-off is lower conductivity, about 32 % IACS.
What does a construction such as 24-5-36 mean?
It means 24 carriers, 5 ends (parallel filaments) per carrier, and 36 AWG filaments of about 0.127 mm. That gives 120 filaments and a metal area of about 1.5 mm².
Can aluminum braid be soldered?
Not easily, because of the tough oxide film. Aluminium braid is normally crimped with aluminium-rated lugs, pressure welded or ultrasonically welded at the ends.
How do I connect aluminium braid to copper busbars?
Use bimetallic copper-aluminium lugs or washers, apply contact compound, and keep the joint protected from moisture to avoid galvanic corrosion.
What shielding coverage can tubular aluminium braid achieve?
Standard sizes are commonly built to around 85 – 90 % optical coverage or more; very small diameters usually achieve less. Shield performance should be confirmed by transfer impedance testing.
Looking for flat or tubular aluminium braid?
Send the width or ID, construction or cross-section, length, termination and quantity to sales@metline.in, and we will reply with a proposal.
