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Automotive Grade Wire: Getting To Understand Different Types of Automotive-Grade Wires

Automotive Grade Wire: Choosing the right wiring harness for your automobile application and maintenance of electrical systems is essential to keeping your car’s electrical system working as designed. 

While there are many types of automobile wires, it can be unclear what wire type is best suited for your wiring harness application.

 We have compiled this article to help you know more about the different automotive-grade wires.

Table of Contents

Automotive grade wire understanding

An automotive wire is a flexible wire that includes stranded conductors for low-voltage automotive systems. 

The conductor materials can be aluminum or copper, with copper automotive wires having better current capacity and durability.

Cross-linked polyethylene (XLPE) and polyvinyl-chloride (PVC) are the most common insulation materials.

Most vehicles use a single conductor, except for certain specialized applications like trailer wiring, speaker wires, and electronic brake cables.

Automotive electrical wire types

By conductor

Automotive wires feature stranded copper conductors consisting of a fairly high number of fine wire strands that ensure resistance to fatigue and flexibility.

You can understand more about automotive-grade wire conductors by comparing them with house and marine-grade wires.

Automotive-grade wire vs house wire

Unlike a house wire, an automotive-grade cable is flexible with several fine cable strands. 

On the other hand, a house wire features a solid conductor, or if stranded cable, uses a small number of fairly heavy-gauge wire strands.

House wire has the following features:

  • Has thicker insulation to withstand the voltage rating of 300V or 600V
  • Does not bend as easily as automotive-grade wires. And can break if flexed continuously.

However, automotive-grade wire can withstand greater temperature extremes compared to house wires.

Besides, automotive-grade wires are approved for car use, while house wires aren’t. Therefore, you should never use standard house wire in automotive applications.

Automotive-grade wire vs marine-grade wire

Find a piece of 10 gauge marine-grade cable and a 10 gauge automotive-grade wire. Without looking too hard, you will realize that the marine-grade wire has many more copper strands.

Besides, if you closely look at the insulation jacket on the two wires, you will see some cryptic lettering on the marine-grade cable and none on the automotive-grade wire.

The number and letters on the marine-grade wire are essential, under ABYC recommendations, for wiring. This information will tell you about the following:

  • The minimum voltage rating of the wire
  • The chemical resistance properties
  • The insulation temperature rating
  • The actual gauge size

Moreover, the strands of the marine-grade wire are silver compared to the copper color of automotive-grade cable. 

The silver color is “tinning,” which is not a standard requirement. Instead, it is to maximize the corrosion effect on the individual strands.

While the actual differential varies slightly from one AWG size to another, the variation percentage is around 10% to 20%. 

The gauge sizing often provides more copper for a given AWG size. The bottom line is that “more copper is better.”

On marine-grade wiring, one of the factors you should always consider is the voltage drop, which is partly controlled by the ability of the wire to carry current with a minimum amount of electrical resistance.

Besides, since the marine-grade wire will have more strands for a certain AWG size, the wire will be more flexible. 

This feature is superior for dealing with the inherent flexing and vibrations in the marine cable wire runs.

By insulation

The most common automotive insulation materials are Cross-linked polyethylene (XLPE) and polyvinyl-chloride (PVC). Both are abrasion-resistant and tough.

By application

The three common types of automotive wires are battery cable, multi-conductor jacket wire, and primary wire.

Primary wire

The term “primary automotive wire” applies to single conductor cables for general vehicle wiring. They are either XLPE-insulated wires or PVC-insulated wires.

Cross-linked automotive-grade wire

Cross-linked automotive wires can withstand aging, extra durability, abrasion, and high heat. They are usually utilized in high-stress applications, such as industrial use vehicles and race cars.

Cross-linked insulation is manufactured by extracting the material through a tube under pressure and heat to “cross-link” or modify the insulation molecules to another state.

A cross-linked automotive wire consists of three different wire types:

Cross-link automotive wire typeDescription

A GXL wire has the following features:
An excellent heat resistance 
A thin wall or thickness
A lighter weight and smaller diameter than standard-duty Type SXL 
A temperature range of -40°C – 125°C

It is mainly used in trailers and trucks for general circuit wiring
SXLAn SXL has the following features:
An excellent abrasion and heat resistance
A temperature range of -40°C – 125°C
A standard wall or thickness

It is ideal for general circuit wiring.
TXLA TXL wire has the following features:
Excellent flexibility and heat resistance 
Extra thin wall and thickness for easy pulling through tight spaces
A temperature range of -40°C – 125°C

It is ideal for general circuit wiring.
Cross-linked automotive wire

Cross-linked automotive wire

PVC automotive-grade wire

PVC is a thermoplastic, synthetic material manufactured through polymerization of vinyl and chloride.

A polyvinyl-chloride automotive wire is often found in cabin or under-hood applications.

It features insulation that is resistant to acids, grease, and oil and is highly durable, making it perfect for automotive, construction, marine, trailer, truck, and many other automobile electrical connections.

A PVC automotive-grade wire consists of three different wire types:

PVC automotive wire typeDescription
GPTA GPT wire has the following features:
A standard wall
A temperature range of -40°C – 85°C 
Excellent resistance to abrasion, heat, and oil

It is often used in trailer wire and general circuit circuit wiring.
TWPATWP wire has the following features:
A temperature rating of 105ºC
A thin wall or thickness
HDTAn HDT wire has the following features:
A temperature rating of 85ºC
A heavy wall

It is designed for surface car electrical systems and is ideal where you need greater physical protection.

Multi-conductor jacket wire

You can use multi-conductor wires with a polyvinyl-chloride (PVC) jacket for exposed wiring subject to road dust and abrasion.

Common applications are for trailer wires and electrical emergency brake cables.

Battery cable

A battery cable is a heavy-duty wire for alternators, battery grounds, and starter wiring circuits.

Battery cables

Battery cables

By colors

Automotive wires come in ten different colors. For applications that need further identification, manufacturers can add 1-3 colored spiral stripes to the existing wires.

Other options are laser marking, inkjet printing, and dying.

By automotive approvals

The three common automotive wire approvals are:

  • SAE J-1128
  • Ford
  • Chrysler

Primary automotive-grade wire overview

Type GXL automotive-grade wireCross-linked-40°C – 125°CFord specification ESB-M1L85-A (tinned copper) ESB-M1L85B (bare copper) , S.A.E J1128
Chrysler specification
Engine compartment – higher heat.
Thin wall (most common)
Type SXL automotive-grade wireCross-linked-40°C – 125°CFord specification ESB-M1L8-A (tinned copper)
Ford specification ESB-M1L85-A (bare copper)
Chrysler specification MS-5919 (bare copper)
Engine compartment where higher resistance is essential.
Standard wall.
Type TXL automotive-grade wireCross-linked-40°C – 125°CFord specification ESB-M1L123-A2 (tinned copper)
Ford specification ESB-M1L123-A (bare copper)
MS-8288 (bare copper)
Smallest and lightweight.
Extra thin wall.

Type GPT automotive-grade wire
PVC-40°C – 85°CSAE J 1128 GXL has a lighter weight and smaller diameter than standard duty S.A.E J1128, Type SXL, and has excellent heat resistanceGeneral circuit wire.
Type TWP automotive-grade wirePVC-40°C – 105°CSAE J 1128Lightweight and small.
Thin wall.
Type HDT automotive-grade wirePVC-40 – 85°CChrysler MS-3494
Ford M1L
S.A.E J-1128
Lightweight and small.
Thin wall.


Understanding your automotive applications, the temperature and environment in which the wire will be used, and how it will be used will help you know the ideal automobile-grade wire you will need.
If you have more questions about automotive-grade wires, contact Cloom via chat, email, or phone. Our knowledgeable and experienced customer support team will be ready to assist.

I am Lillian Yang, having been a sales manager for over 10 years.

I have received many positive reviews from customers. They have praised our excellent service, on-time delivery, and high-quality cable assemblies.

For your projects, please provide cable assembly files/images/smples, etc., so that I can send you a quotation within 24 hours.

Contact me now and let’s get started on building your wire harnesses!

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