Big 3 Upgrade Electrical Wiring Kit - High Output Car Audio Upgrade

In this review the Big 3 Upgrade Electrical Wiring Kit is judged primarily as a targeted solution for owners upgrading car audio or high-output charging systems. It is best for people who need to relieve electrical load, fix dimming headlights, or support a high-output alternator because the kit replaces three critical conductors with oversized, pure copper wiring to improve current flow and system stability.

Key Features

• 100% Pure Copper Conductors: Oxygen-free high-strand-count OFC wire improves conductivity and reduces electrical resistance for stronger current carrying capacity.
• Tin-Plated Terminals: Terminals are tin-plated to resist oxidation and corrosion for longer-term stable connections under vehicle conditions.
• Flexible Jacket and Form Factor: The soft, tear-resistant jacket with an OD near 14mm bends easily for routing in tight engine bays and retains tensile strength over time.
• Full Big 3 Upgrade: The kit replaces battery negative to chassis, engine to chassis ground, and alternator power to chassis to reduce voltage drops and stabilize system voltage.
• High Current and Safety Ratings: Supports up to 350A and 600V, and uses flame-retardant insulation with wide temperature range to protect against heat and vibration.
• Installer-Friendly Kit Contents: Includes pre-cut 0 AWG ground and power leads, ring terminals, clamps, screws, zip ties, heat shrink and flame-retardant tape for a complete install.

Who It's For

The kit is aimed at car and truck owners upgrading audio systems, installing high-output alternators, or troubleshooting dimming lights and unstable voltage. Enthusiasts who plan a clean, permanent installation will appreciate the included terminals, clamps and heat shrink that simplify routing and termination.

It is less suited for those who only need a single replacement cable or who require professional custom-length fabrication beyond the supplied lengths. Buyers who want a fully plug-and-play harness with matched connectors for a specific amp may prefer a different product tailored to that amplifier.

Pros & Cons

Pros

• High-strand OFC copper improves current flow and can noticeably stabilize electrical systems under load.
• Durable, flexible jacket and tin-plated terminals reduce corrosion and make routing easier in tight spaces.
• Comprehensive kit contents support a complete Big 3 upgrade without sourcing extra parts.

Cons

• Pre-cut lengths may not suit every vehicle layout and some trimming or extension could be necessary.
• Not intended as a universal plug-and-play amp harness for devices needing proprietary connectors.

Specifications

Our Verdict

The Big 3 Upgrade kit is a practical, value-focused solution for owners upgrading vehicle electrical capacity for audio or alternator projects. Its pure OFC conductors, corrosion-resistant terminals and full accessory set make it an effective way to reduce voltage drop and improve system reliability, though installers should confirm supplied lengths match their vehicle before beginning work.

Frequently Asked Questions

Will this kit work with a high-output alternator?
Yes. The wires are rated to support high-output alternators with a 350A current capability and 600V rating.

Are the terminals corrosion resistant?
Yes. The kit uses tin-plated terminals designed to resist oxidation and corrosion over long-term use.

Do the supplied lengths fit every vehicle?
The kit includes 4 ft and 6 ft 0 AWG leads which cover many installations, but some vehicles may require longer runs or custom routing.