Whether you're a mechanic or procurement specialist, knowing how to read automotive cable specifications is the secret to a successful installation. The right cable ensures safety, reliability and performance, especially in today's complex systems.

In this short guide, we'll cut through the technical jargon and explain how to read cable labels with practical, real-world examples.

Breaking down the specs

The world of cable specifications doesn't have to be confusing – not when you understand key terminology. The following sections clarify phrases you'll hear time and time again in the automotive industry.

Cross-sectional area (mm² or AWG)

A cable's cross-sectional area, measured in square millimetres (mm²) or American Wire Gauge (AWG), refers to the thickness of the conductive core – not the overall diameter of a cable, which includes insulation and protective layers.

Why is the cross-sectional area important? Basically, it determines how much electrical current a wire can safely carry. The larger the cross-sectional area, the more power it can handle without overheating.

Thicker wires are ideal for heavy-duty applications that demand large amounts of current, such as connecting an EV battery to its motor controller.

Voltage rating

Voltage rating refers to the maximum voltage a cable can handle under normal operating conditions.

Choosing an appropriate voltage rating guarantees reliable performance while minimising unnecessary increases in cost, size and weight. Think of voltage like a water hose – if the water pressure (voltage) is too high, the hose (cable) might burst.

Temperature rating

The temperature rating defines the range of temperatures a cable can operate within without compromising performance.

It's typically divided into two parts: the maximum operating temperature and the minimum installation temperature.

• Maximum operating temperature is the highest temperature a cable can handle without melting or cracking.
• Minimum installation temperature is the lowest temperature a cable can handle without damaging the insulation.

Insulation types

Different insulation types serve specific purposes, so it's essential to know exactly what you're getting. Here are five of the most common:

• PVC (polyvinyl chloride) – A versatile insulation used in general-purpose wiring for low- to medium-temperature environments.
• XLPE (cross-linked polyethylene) – Offers excellent thermal, chemical and mechanical resistance, making it ideal for high-heat zones.
• Silicone — Highly flexible and commonly used to withstand moving parts.
• TPE (thermoplastic elastomer) – Known for its high heat resistance (up to 250°C), so well suited for engine bays and EV power systems.
• ETFE (Ethylene Tetrafluoroethylene) – A premium insulation with outstanding heat, chemical and abrasion resistance, typically used in aerospace and high-performance automotive systems.

Related reading: A Quick Guide to Cable Covers & Protectors

Number of strands

The number of strands refers to how many individual copper wires are twisted together to form a single conductor. More strands mean greater flexibility, which is important when wiring moving parts and vibration-prone areas.

Colour coding

Automotive cables have different outer insulation colours depending on their function, which reduces wiring errors. Since colour codes vary between manufacturers and regions, it’s important to check the supplier’s instructions before starting work.

How to read a cable label

It's time to put everything we've learnt in this guide into practice. Let's break down the following cable specification as an example:

35mm² PVC 600V red battery cable

• 35mm² – the cross-sectional area of the conductor
• PVC – the insulation material
• 600V – the maximum voltage it can safely handle
• Red – the insulation colour, often used for positive battery leads
• Battery cable – indicates the cable’s intended use

Choose the right cables for your project

As a rule: When in doubt, check the spec. Understanding automotive cable specifications will ensure you always deliver the highest-quality work, free from expensive and time-consuming hiccups. 

If you need more advice on cable management, contact our team today.