What Gauge Is Trailer Wire?

Aichie Tech Electronic makes trailer cables that are very durable and soft even for cold winter use. Because our sheath thickness is thicker than other factories. So our cables are resistant to friction and can move freely. Our trailer harness is also oil resistant.

The specifications of the trailer cable you choose will depend on the type of trailer and the application of the trailer cable. Suppose you are buying trailer cables for a 7-blade RV connector. In general, for 7-way trailer wire connectors, experts recommend using wire 12AWG for red or black (power) wire, white (ground) wire, and blue (brake power) wire. However, 16 gauge trailer wire is the minimum recommended for the remaining connections, including brown (tail light) wire, yellow (left turn/brake) wire, green (right turn/brake) wire, and purple (reverse light) trailer  cable.

However, if you want to connect different types of applications, your choice of trailer wiring will change. For example, if you have a 8 foot x 35 trailer and you intend to place heavy objects on it, you may need heavier trailer cables to support the application. As a general rule, a project like this usually requires a 16 awg trailer wire. However, if the trailer is longer, you may need a heavier wire gauge - for example, maybe a 14 gauge trailer wire will solve the problem, or maybe even a 12 gauge specification might be called for.

Now turn to slightly different trailer cable application. If you have a 10-foot camper and are working on projects such as license plate lights and wiring of two brake lights, your trailer cable size will be different from the first two applications. In general, if you use LED lights, then a 16awg trailer cable should be fine.

But some types of lights use more power than leds, or your lights may be more than a "typical" trailer. In this case, your choice of trailer cable must also be changed. In this case, a heavy duty trailer cable is recommended. For example, on a 7-way connector, running more lights than usual, or lighting multiple lights at once requires 14/7 trailer wire or even thicker wires, such as 12/7 AWG.

How to install trailer cable?

The general process for installing trailer cables is the same/similar for all applications, regardless of the trailer wire size you use. However, the specifics vary when it comes to the number of connectors involved in trailer wiring.

To correctly install 4-way trailer cable, you can refer to the following wire connection coding:

Ground = White

Tail/Running lights = Brown

Left turn/Brake = Yellow

Right turn/Brake = Green

Note that when using a 4-wire tow line, the left/brake light (yellow) line connector is marked with "L", while the right/brake (green) tow line connector is marked with "R" it.

However, when using a 7-core trailer cable, the installation requires some additional connections. For example, to properly install a 14/7 trailer cable, you would first follow the first four specified steps for using a 4-wire trailer cable installation.

Then, the 7-core tow wire requires three additional connections:

Red auxiliary 12V power supply/reverse light/reverse lock for trailer brakes

Blue brake controller output

Black 12V battery power

The picture above should give you a good idea of how to install 7 way trailer wiring.  If you follow the pin configuration, features, and color codes listed in the diagram, you will have a successful installation.