OEX ACX3057BL Blue Insulated Ring Crimp Terminals 10.5mm (14 Pack)

Heavy-duty blue ring terminals for high-current automotive connections

Product Overview

The OEX ACX3057BL insulated ring crimp terminals handle the serious current loads demanded by modern automotive electrical systems. Designed for 4.0mm² cable—the wire size commonly used for high-draw accessories like winches, inverters, and auxiliary battery connections—these 10.5mm internal diameter terminals fit M10 studs found on battery posts, starter motor terminals, alternator connections, and heavy-duty distribution blocks. The blue vinyl insulation instantly identifies these as 4.0mm² terminals, preventing dangerous mismatches when you're working with multiple wire gauges in complex power systems.

Each terminal features double crimp construction with separate crimps for the conductor and insulation, delivering both excellent electrical contact and mechanical strain relief. This matters when terminals face constant vibration from corrugations, thermal cycling under the bonnet, and the physical stress of high-amperage current flow. Tin-plated copper construction provides superior conductivity while resisting the corrosion that destroys electrical connections in Australian conditions—from coastal salt spray to inland dust and heat.

Supplied in a 14-piece pack, this quantity suits specific installations where you need multiple high-current connections: dual battery setups requiring several earth and positive terminations, custom switch panel builds with multiple power feeds, or maintaining a small inventory of the most critical terminal sizes without overstocking bulk quantities.

Key Specifications

• Terminal type: Insulated ring (eyelet style)
• Internal diameter: 10.5mm (suits M10 studs/bolts)
• Wire size range: 4.0mm² conductor
• Insulation colour: Blue (4.0mm² standard colour code)
• Insulation material: Vinyl (PVC)
• Terminal material: Tin-plated copper
• Crimp style: Double crimp (conductor + insulation)
• Pack quantity: 14 pieces
• Warranty: One year manufacturer warranty

Features & Benefits

10.5mm Internal Diameter – Fits M10 studs and bolts, the size commonly used for battery terminals, starter motor connections, alternator B+ posts, and heavy-duty earth points. The full 360-degree contact around the stud provides maximum current-carrying capacity and vibration resistance—critical for high-amperage automotive connections that can't tolerate resistance or loosening.

4.0mm² Wire Capacity – Designed specifically for 4.0mm² cable, the wire size that handles 30-50+ amp continuous loads in 12V systems. This makes these terminals essential for winch installations, inverter power feeds, dual battery isolator connections, and any accessory drawing serious current where undersized wire creates voltage drop and heat issues.

Double Crimp Design – Separate crimps for the wire conductor and insulation jacket ensure proper electrical contact and strain relief. The conductor crimp creates low-resistance connection for efficient current flow, while the insulation crimp prevents wire flex fatigue at the terminal entry—particularly important in underbonnet installations where vibration and heat cycling cause premature failures in single-crimp terminals.

Tin-Plated Copper Construction – Copper delivers excellent conductivity with minimal voltage drop, while tin plating protects against oxidation and corrosion. In Australian conditions—from tropical humidity to outback dust and coastal salt exposure—tin plating significantly extends terminal life compared to bare copper, maintaining low-resistance connections over years of service.

Blue Colour Coding – The blue vinyl insulation follows industry-standard colour coding for 4.0mm² wire terminals, providing instant visual identification during installation and future maintenance. When you're troubleshooting an electrical system months after installation or another electrician needs to work on your wiring, that colour coding prevents dangerous terminal-to-wire mismatches.

14-Piece Pack Size – Targeted quantity for specific high-current installations without excessive inventory. Ideal for dual battery systems (requiring multiple positive and earth connections), custom electrical builds, or maintaining workshop stock of critical heavy-duty terminal sizes without bulk-pack expense.

Technical Specs

• Terminal designation: Insulated ring terminal (eyelet crimp style)
• Ring internal diameter: 10.5mm (M10 stud compatibility)
• Stud/bolt size compatibility: M10 threaded fasteners
• Wire conductor range: 4.0mm² cross-sectional area
• Insulation sleeve colour: Blue (industry standard for 4.0mm²)
• Insulation material: Vinyl (PVC) compound
• Terminal conductor material: Tin-plated copper alloy
• Crimp configuration: Double crimp (wire barrel + insulation barrel)
• Terminal barrel internal dimensions: Sized for 4.0mm² stranded wire
• Current capacity: Rated for high-amperage automotive applications (30-50A+ continuous depending on wire length and installation)
• Pack configuration: 14 terminals per pack
• Quality standard: Manufactured to automotive crimp terminal specifications
• Warranty coverage: 1 year from purchase date

Compatible With / Goes Well With

• 4.0mm² automotive cable (various colours for different circuits)
• M10 studs, bolts, and threaded battery posts
• Heavy-duty ratcheting crimp tools with 4.0mm² dies
• Battery terminal distribution blocks with M10 studs
• Dual battery isolators and smart battery combiners
• High-current circuit breakers and fuse holders
• Wire strippers calibrated for 4.0mm² cable
• Heat shrink tubing for additional connection protection
• Dielectric grease for corrosion prevention
• Torque wrench for proper terminal installation (typically 8-10Nm for M10)
• Winch installation kits and power cable assemblies
• Inverter power connection hardware

Note: Always verify stud/bolt diameter before purchasing. 10.5mm ID terminals require M10 fasteners—using incorrect terminal sizes creates loose connections with high resistance and potential fire risk.

Frequently Asked Questions

What crimping tool do I need for 4.0mm² terminals?  Use a heavy-duty ratcheting crimp tool with dies sized for insulated terminals in the 4.0mm²/blue wire range. Quality tools ensure both conductor and insulation crimps close correctly with proper compression—standard automotive crimp tools may not have sufficient leverage for 4.0mm² wire, requiring professional-grade tools.

Can I use these for winch power connections? Yes, 4.0mm² wire and properly crimped ring terminals are standard for winch installations up to 12,000lb rating on short cable runs (under 3 metres from battery). For longer runs or higher-draw winches, verify wire sizing calculations account for voltage drop—you may require larger cable.

Will these fit standard car battery terminals? Most standard car batteries use larger terminal posts (typically requiring 13mm+ internal diameter ring terminals), but auxiliary batteries, distribution blocks, and some European battery designs use M10 studs where these 10.5mm terminals fit perfectly. Always verify stud size before purchasing.

Are these suitable for permanent underbonnet installation? Yes, tin-plated copper resists corrosion and vinyl insulation handles automotive temperature ranges. For maximum longevity in harsh environments, apply dielectric grease to connections, properly torque terminals to manufacturer specifications, and protect exposed connections with heatshrink tubing or terminal boots.

Can I connect 2.5mm² or 6.0mm² wire if I don't have the correct terminals? No—always match terminal size to wire gauge. Using oversized terminals on undersized wire creates poor crimps with high resistance and potential overheating. Using undersized terminals on oversized wire is impossible to crimp properly. Correct terminal-to-wire matching is essential for safe, reliable electrical connections.