Jumper Cables Melted: Possible Causes & Solutions

Having their cars’ batteries die sounds like a nightmare to everyone. When that happens, the first thing you should look for is a jumper cable.

But have you ever tried to jumpstart your car just to see your jumper cables melted? That’s like adding salt to the injury! 

This technical issue can happen to anyone, but not all of us know how to handle it. Worry no more; you are at the right place!

In this article, we will provide complete information about why your jumper cable gets smoking hot or melts during jumpstart, as well as some methods to deal with the problem. Let’s get started! 

So What Is A Jumper Cable?

Jumper Cables Melted

Most traditional vehicle types, including cars, run on gasoline. That’s something we already know. To start the car, though, we need the car battery.

When you turn the key, and the engine fails to start or when the battery doesn’t hold a charge, it is probably dead, and that’s when you need a jumper cable.

Simply put, a jumper cable is a pair of thick electric cables fitted with alligator clips at both ends. Sometimes, it’s referred to as a booster cable or jump lead.

As you can see from many car battery cables, a set often has two cables of different colors (red and black, black and white, etc.):

To jumpstart your car with a jumper cable, you use the alligator clips to connect the battery with another energy source (typically a portable jump starter or a functional vehicle).

This allows the car to charge the battery and get started, so you can drive it off to the mechanic’s shop and find out the underlying issue. 

Many factors can affect a vehicle’s battery life. Weather, forgetting to turn off the lights, or an old/dysfunctional battery are just some of them.

That’s why keeping a jumper cable with you and knowing how to use it are extremely helpful.

However, even this emergency equipment can fail. In some cases, you might see your jumper cables melt and don’t even know what’s happening.

Jumper Cables Melted: The Common Causes

So what causes jumper cables to melt? Well, there are five main reasons:  Wrong or reversed cable connection, loose connection, low-quality jumper cables, damaged jumper cables, or a short in the car you want to jump.

Below, we will go deeper into each of them.

Common Causes

Wrong Or Reserved Cable Connection 

The most common reason for smoking or melted jumper cables is reversing the connections to the wrong terminal.

When you mistakenly connect the jumper cables, electricity will flow backward through the dead battery.

Automotive mechanics refer to the issue as “reversed polarity“. Within a few seconds, the current flow will release excessive heat, which melts down the jumper cables’ plastic and rubber installations.

Reserving the jumper cables can create disastrous results, including severe damage to the battery and fried electronics.

Under normal conditions, a regular car battery doesn’t have enough voltage to cause serious personal injury, but there have been numerous records of people being shocked by reserved cable connections.

In case you feel a slight tingle or an electric shock, uncrossing the cables will get the polarity back to normal. Keep in mind that the current doesn’t go down to zero immediately, so proceed with caution.

Loose Connections 

Even if you have connected the jumper cables to the battery source, a loose connection can also result in overheating.

There is a significant amount of electrical current trying to get from one battery to the other. Therefore, electricity will leak and overheat the cables when a connection isn’t fully snug.

If you only get your jumper cable melted, you are lucky. Loose connections may also lead to short-circuiting, which damages the car’s electrical system.

The jumper cable or car battery can catch fire in extreme cases.

Low-Quality Jumper Cables

Sometimes, the culprit behind the issue above is a low-quality jumper cable.

Jumpstarting a dead car battery is quick and easy with a proper jumper cable. However, many manufacturers out there use cheap materials to reduce production costs, and it’s the consumers who suffer.

A good pair of jumper cables should feature clamps with “alligator teeth, ” providing the best bite. Ineffective clamps made of poor materials will make it hard to secure the connections and, well, you know the result.

Additionally, cable wires are made using metallic components. When electricity flows through the wire, each metal will react differently.

Although copper is often the ideal material since it does not become overheated quickly, many manufacturers will opt for aluminum wires since they are less expensive.

An aluminum jumper cable requires more electricity to transmit power from one battery to the other. That means your cable is more likely to get melted.

Damaged Jumper Cables 

How you store your jumper cables affects their performance. To ensure your lines function properly, don’t forget to keep them in optimal condition.

Exposing the insulation to poor conditions can damage the copper inside. This affects the wires’ ability to transport electricity.

Using these wires to jumpstart the battery may create dangerous currents that melt down the connection and even wreck your vehicle.

A Short In The Car You Want To Jump

The last thing that can get your jumper cable melted is a short in the car you want to jump.

For example, your vehicle has a battery of 12 V, but the donor car’s battery is 24 V. When this happens, the jumper cables will heat, smoke, and melt immediately.

How To Fix Or Prevent Jumper Cables From Melting?

How To Fix Jumper Cables From Melting

Unfortunately, there is no way to fix melted jumper cables. They are no longer safe to use anyway.

Still, as long as you stick to this safety guideline, it’s possible to avoid cable melting: 

Follow The Safe Order To Attach Jumper Cables

To avoid major problems, such as reversed polarity, you should connect jumper cables to the battery properly.

According to technicians, this is the safest order to attach jumper cables: 

  • Connect one end of the positive (red) jumper cable to the flat battery’s positive (+) terminal.
  • Attach the other end of the positive (red) jumper cable to the donor battery’s positive (+) terminal.
  • Attach one end of the negative (black) jumper cable to the donor battery’s negative (-) terminal.
  • Connect the other end of the black jumper cable to a metal part (unpainted) on the car with the flat battery.

Some say attaching the last jumper cable clamp to the negative terminal on the dead car’s battery is fine.

However, this increases the risk of explosion if the jumpstart doesn’t go as planned, so we don’t recommend doing so. Remember to tighten the battery terminals at the end.

Double-Check The Connections 

To prevent loose terminal connections, double-check them by lightly tapping the jumper cable with your hand. If they aren’t snug, fit them in before connecting the batteries.

Store Your Jumper Cables Properly 

As the previous part mentioned, keeping jumper cables in good condition is crucial when you don’t use them.

The best way is to store them in a protective bag. When you purchase, most cables should come with one.

Avoid getting the bag wet and clean it regularly to remove any dirt or rust that may form on the leads.

Cables can rust on the inside, too, and this is more difficult to detect. Still, you shouldn’t have any problems as long as you keep the cables away from moisture.

Invest In Good Quality Wires

Jumper cables might look all the same – two long cords, each has a clamp at either end. Nonetheless, inexpensive jumper cables are more likely to melt than a higher-quality set.

Instead of saving a few bucks, getting solid wires will save you from a lot of trouble in the future. A worthwhile investment, we’d say.

What To Look For When Choosing Jumper Cables To Prevent Melting?

With that in mind, there are a few factors you’d want to consider while picking a good set of jumper cables. Let’s go over them in detail.


What’s a jumper cable’s “rating,” you might ask? Well, it’s the gauge of the wiring used to construct the line. The wiring lies beneath the outer insulation, which shields your cable from environmental harm.

The lower the rating, the thicker the cable. When it comes to jumper cables, you will want to stick with heavy-duty ones because the current flow should be high enough to jumpstart the vehicle.

Hence, 1- or 2-gauge lines yield the best results, while 9- and 10- cables only work with compact cars.

However, thicker cables often come at a hefty price. Thus, general users should choose those in the 4- to 6- gauge range. They are robust enough for emergency use yet still keep you on a budget.

Cable Insulation 

Due to the minimal insulation used to protect the internal metal wiring, cheaper jumper cables tend to be very frail.

If you are looking for heavy-duty jumper cables, expect thick and sturdy insulation. Heavier insulation shields the inside from the heat generated during the jumpstart process.

This goes a long way in ensuring their longevity and boosts the cables’ functionality.

Cables with thick insulation are more difficult to bend. Put out the extra cash for a high-quality, long-lasting set to ensure the best performance.


Length is another critical factor.

With a short jumper cable, you will have difficulty jumpstarting your vehicle. A length of approximately 10 feet should be sufficient for most situations.

Nonetheless, you never know what kind of circumstance you will be in when your car’s battery dies.

For example, if you park your vehicle in certain ways, a 10-feet long cable might not be enough to give it a jumpstart from another car.

As such, consider investing in a 25-foot jumper cable. These cables are a bit more expensive, but on the bright side, you can rest assured that they work in any situation.


Without a reliable connection for the electricity to travel through, you won’t be able to give your battery the boost it needs to charge.

Therefore, inadequate metal, such as aluminum, will make it hard to jump-start the car effectively. Aluminum wires take much longer than copper ones to work, and they risk getting your jumper cable melted.

Among all the metals, solid copper is one of the most efficient conductors of electricity. Regarding jumping a dead car battery, sticking with copper wires is the best choice.

Those with a tight budget can opt for copper-clad aluminum jumper cables. Of course, they are not as robust as copper ones, but they still provide the necessary conduction for a successful jump-start.


The design of your jumper cables’ clamps can determine whether you will get snug and secure or loose connections.

As a rule of thumb, clamps with good, strong “alligator teeth” are the most reliable.

Better teeth can also be attached in different positions, which is extremely useful with several battery posts’ location and accessibility.

Also, take your time examining the handle portions. They should be made of sturdy and secure insulation so that you won’t electrocute yourself.

Many poor-quality cable sets come with loose-fitting handle insulation, and trust us, getting an electric shock is not a pleasant experience.


Can You Still Use Melted Jumper Cables?

No, you can’t.

A broken insulator increases the risk of fire and short-circuiting, both of which might cause irreparable damage to your car. In many cases, melted jumper cables also lead to serious personal injury.

When the plastic and rubber insulators start to melt, the best thing is to get a new set of jumper cables right away.

Are Jumper Cables Expensive To Replace?

In general, they don’t. However, it also depends on what type of jumper cables you choose.

Shorter and slimmer wires tend to be cheaper than longer and thicker ones. A standard 4-gauge, 20-foot cable costs around $25 to $30. Unless you are a technician, you won’t need anything more expensive than that.

Can You Jumpstart A Dead Car Battery Without Jumper Cables?

Yes, you can.

To jumpstart your vehicle without jumper cables, apply the push-start method, use a portable charger, or call a roadside assistance service.

The Bottom Line

Now you know what to do if you get your jumper cables melted!

This is a common problem, but as long as you invest in good quality equipment and follow our tips, you can proactively avoid unfortunate situations.

Thank you, and see you in the next post!

Leave a Comment