When building a car audio system, the choice of cables and conductors is not a secondary detail: it directly affects the effective power, safety and lifespan of the system.
Many inexpensive commercial products use materials such as aluminum or brass , but the technical difference with pure copper is substantial.
In this article, we explain why copper is superior, how to size your cables, and why ISP Audio fuse blocks really make a difference.

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Comparison of conductive materials

The conductivity and resistance of materials determine how much current can pass without causing voltage drops or overheating. Here's a clear table:

What this means in practice:

• Copper transmits current more efficiently → lower losses and maximum amplifier performance.

• Lower internal resistance → less heat and risk of overheating.

• Greater stability over time → less oxidation and reduced maintenance.

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Cable sizing

Correct cable sizing is essential to ensure all the power reaches your system without losses.

Simple current calculation

$$I (A) = \frac{P_\text{RMS} (W)}{V_\text{batt} (V)}$$

• $P_\text{RMS}$ = real power of the amplifier

• $V_\text{batt}$ = system voltage (typically 12 V)

Example: a 300W RMS amplifier →

$$I = \frac{300}{13} \approx 23\,A$$

Note: This value is empirical . Each amplifier has different efficiency based on its class (A, AB, D, Digital) and internal construction. Actual current may therefore vary.

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Cable capacity based on material and length

The following table shows the indicative cable range for typical car audio installations (distances up to 3–5 m).

Aluminum's current carrying capacity is approximately 0.78 times that of copper for the same cross-section. This means that thicker cables are needed for the same current.

Rule of thumb: Copper can handle about 4/4.5 A/mm² over lengths up to 5 meters , while aluminum typically reaches ~3 A/mm².

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Durability and reliability over time

Pure copper cables offer tangible advantages:

• Reduced oxidation: connections remain efficient for years.

• Thermal stability: less heat generated means a safer and longer-lasting system.

• Minimal maintenance: Copper cables maintain performance even under difficult conditions (vibrations, variable temperatures).

Aluminum, on the other hand, tends to oxidize more quickly and requires greater attention to the joints.

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ISP Audio Fuses: Pure Copper Only

All ISP Audio fuse blocks are made exclusively of pure copper. The advantages are clear:

Why it makes the difference:

1. Current flowing without bottlenecks → maximum system efficiency.

2. Stable connections → no risk of overheating.

3. Longer duration → investment that remains valid over time.

Compared to many commercial distribution blocks, our fuse blocks do not introduce losses or critical points : the current reaches the system without obstacles, even under high loads.

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To conclude

Choosing pure copper isn't just a matter of perceived quality: it means more usable power , lower losses , secure connections and longer life .

ISP Audio cables and fuses ensure your car audio system operates at peak performance, safely and without compromise, today and for years to come.