If you constantly ask what causes alternator wire to melt, the answer to that question depends on many factors. You need to consider whether you just had your alternator battery changed. If yes, you may have made a big mistake with the wire.
Other problems can cause your wiring to melt, like having a battery too big for your vehicle, high voltage, and more.
Your alternator is built to give your vehicle a long-lasting service that is trusted. Unfortunately, many vehicle users have complained about an unusual problem with their alternator wire. The problem is that the wires leading to the alternator often get too hot and, in extreme cases, melt wire.
Some factors can cause this to happen like wrong size wiring, high voltage, faulty electrical connection or overcharged alternator etc. The details are following.
1. Undersized Alternator ground wiring
If you have upgraded your alternator wiring recently, you might have gotten undersized wiring. Many people need to understand that each electrical component has a recommended wiring size.
When the alternator connector melted after you changed the wiring, it was most likely the wires were too small to handle the current coming from the alternator. You have to get the recommended wiring for your alternator.
2. High voltage
Another reason that your wiring might be running hot is due to the high voltage. The normal alternator output is between 13.5 to 14.5 volts. When the volt goes higher to 14.5, it is too high and could cause the wire to run too hot because it is not built to handle that voltage level.
You will have to get your alternator checked if this happens too often.
3. Faulty electrical connection
The most common cause of the hot or melted alternator cable is a corroded or loose connection in the alternator wire to battery.
When there is a loose or weak connection, the flow of current is reduced by the resistance created by the weak connection causing the wires to be too hot, which could eventually lead to melted alternator wires.
4. Short Circuit
When there is a short in the electric current supplies from the alternator, it could lead to a high power draw causing the alternator hot to touch.
The short circuit could cause the wires to melt and touch each other.
Three wires are connected to the alternator and come in different colors for easy identification. Three wires are connected to the alternator because the alternator powers many components in the vehicle.
The major wires connected to the alternator are the exciter, positive, and negative. Exciter wire powers the voltage regulator. It should be able to carry about 12.5 volts.
Furthermore, the positive wire, the red, goes from the alternator to the battery. The wire has the function of powering the battery. If this wire is faulty, the battery will not charge properly, and your battery will quickly drain.
In addition, the negative wire, which comes in black, runs from the alternator to your vehicle's chassis, which acts as the alternator ground wire. The wire aids in dropping the interference in the electrical system.
It is quite dangerous to mix up the alternator cables because it could cause the alternator to stop working, and at worst, it could stop the engine due to a drained battery.
The cables connected to the alternator are different in size. The Exciter cable is bigger, and this is because it is meant to allow more voltage to the voltage regulator through the L terminal. It generates the voltage needed by the alternator to start.
On the other hand, the positive and negative wires are much smaller than the exciter cables.
Having the wires mixed up will mean using a positive or negative wire to the L terminal, which requires a bigger wire. The wires will overheat and melt if used in this condition for too long; the wire will eventually fail, causing the alternator to stop working.
You can not use one wire with your alternator unless you will be replacing your alternator with a one-wire alternator. The alternator uses one wire to link the alternator to the battery. All other wiring is internal.
However, using this alternator does not mean you will not use ground wire connecting the alternator to the engine chassis.
A one-wire alternator will require ground wiring to connect it to the chassis. For the alternator to charge correctly, the alternator must be grounded to the engine block. Mounting it on the engine block will give the alternator a good link to the chassis.
It is important to understand that you must use the appropriate wires that belong to the right gauge. The wiring is less complicated when compared to the regular alternator.
Before we move on, ensure that the wire is not mounted to moving parts to avoid wire damage.
Many people feel that a bigger battery should not affect the alternator, but it could hurt it long-term. A bigger battery will cause your alternator to heat more quickly. If this continues, it will shorten the alternator's life.
It would help if you got a battery that fits your vehicle but is also a great combination for your alternator.
A bigger battery would also increase the level of voltage going to other components of your vehicle. It may damage the fuse, computer system, and other electronic parts.
An alternator amp may range from as low as 60 amps to as much as 150 amps or even more in a modern vehicle. There are also high-output alternators that can generate as high as 200 amps.
What amp is too high depends on the vehicle you are using and what type of alternator you have in your vehicle. A good alternator amp rating is directly related to its electric system.
What causes alternator wire to melt is mainly related to wiring, alternator, or battery issue. When you notice this in your vehicle, you should get these parts checked properly. Also, ensure that your battery is manageable for your alternator to avoid wiring problems and faulty alternators in the future.