When does Wire become Cable?

We are all familiar with the terms wire and cable. It doesn’t matter if we’re new to boating, a master at 8 gauge marine wiring, or have never boated, we still know what wire and cable are. Or do we? The most common answer that you are likely to hear is that wire is thinner, and cable is thicker. While this is true, the answer is just not that simple. This table to the left demonstrates the difference gauges sizes as categorized by being either wire or cable. The problem is, this table doesn't explain why they are different. Let’s start by clearly defining what we mean when we use the word wire.

What do we mean by wire?

When we refer to wire, we are referring to a strand of flexible metal that is designed and manufactured to transmit electricity. The larger the diameter of this strand of metal, the more electricity it can carry. The thing is, if the diameter gets too large, then you begin to lose flexibility and the solid strand is more subject to damage from stress caused by bending, vibration, and flux. Suppose you’re working on 8 gauge marine wiring in tight spaces. In this case, flexibility is an absolute must. Is there a solution to this issue? Of course. Instead of one large-diameter strand, we’ll use multiple smaller strands together. When we bundle several smaller strands together, we get the same current carrying capacity and we do not have to sacrifice flexibility or durability. These bundled strands of wires are called ropes.

Wire versus Cable

Let’s look at an example. Here is a 16 gauge Pacer marine wire. This wire is comprised of 26 individual strands of tinned copper. Each of those individual strands is considered 30 gauge wire. With all 24 strands of 30 gauge wire wrapped together, we now have that rope that we mentioned above. You can see how the individual wires within the rope allow for bending and flexing stresses to be displaced which in turn reduces the risk of damage to the wire.

Here's another example. This is a 4 gauge marine battery cable, and you can see that it contains seven individual ropes. Each of those ropes contains sixty 30 gauge wires. So in essence, a stranded 4 gauge battery cable is made up of 420 strands of 30 gauge wire. To recap, a wire is a single strand of conductive metal, or it is multiple strands of that same metal combined to be a rope. In contrast, a cable is where you have multiple ropes together.

What about 8 gauge marine wiring?

So our rule about multiple ropes combined becoming a cable doesn’t hold up to 8 gauge marine wire, does it? When it comes to 8 gauge marine wiring, you’ll notice that although 8 gauge is considered wire it contains multiple ropes meeting the criteria for a cable. Why is that? The truth is that the word cable implies a certain degree of size. That is to say that when you use the word cable, you are implying something somewhat large. In the end, 8 gauge marine wiring just isn’t that large and so it tends to be considered wire rather than cable.

What sizes are Pacer marine wire and battery cable?

When it comes to Pacer marine wire and battery cable, we consider our 22 gauge through our 8 gauge to be wire and our 6 gauge through 4/0 aught to be cable. This straightforward system makes choosing the correct type of marine wire or battery cable for your application an easy choice. Whether you’re working on 8 gauge marine wiring or 16 gauge wiring, knowing the correct sizing makes all the difference.