If for any reason you must disconnect a cable from the car battery, you must know exactly What is disconnected first in a battery? don’t ever think of disconnecting the positive (+) battery cable first. A small touch from the wrench or tool used creates a direct short to ground. The Negative (-) wire is the ground wireis always connected to the frame or to any metal part of the car, and can be safely disconnected first, without causing sparks, or even a fire.
What is disconnected first in a battery?
When it is not known which is the terminal that must be disconnected first in a battery, if it is the positive or the negative, we enter into a dangerous doubt. The cables, it is not a simple wiring that can be disconnected randomly in a vehicle battery. Then, the first thing to safely remove is the negative battery terminal before the positive terminal, if you were to disconnect the positive terminal with the key you used and it touches or rubs against the metal bodywork or the engine block it would cause a spark that would damage the battery. It is important to consider the following, while the process of connecting the battery starts with the positive terminal, to disconnect the battery you must start with the negative terminal.
Why is the battery negative disconnected first?
The negative (-) ground terminal is disconnected first to ensure that a short circuit to the battery occurs. Otherwise, it may generate an electric shock or cause a fire, with the use of the tool to disconnect the positive cable touch any metal surface of the car connected to the ground. When the negative battery cable is disconnected, you are disconnecting the battery from the car’s chassis.
In case of starting the process of extracting the positive first, before the negative and the used key or tool comes into contact with a metallic part of the car, it can cause a short circuit in the electrical system, affecting the fuses and relay, some electronic components and they will be scorched. Which translates if in case of first disconnecting the positive cable you will make a serious mistake and as a consequence you will have something of a risk, not only for you but for your car. Remember that the key or tool used may come into contact with a grounded metal part of the car, generating an electric shock or even a fire.
Q: Is it correct to disconnect the positive terminal?
whatever the situation, The first thing to do is disconnect the negative battery terminal instead of the positive. If you are preventing the battery from discharging, you can achieve this by disconnecting the positive or negative first. Enough with disconnecting one wire, it is because disconnecting any of the wires produces an open circuit, which does not allow the flow of current. Although disconnecting the positive terminal, while the negative terminal is connected may result in a hazard by causing electrocution or fire.
By disconnecting the battery You must keep in mind that you must first remove the cables from the negative terminal, they are generally the black cables, with a minus sign (-), and then proceed to disconnect the cables from the red positive terminal, with a plus sign (+). You should also be very careful not to accidentally touch a metal object to both battery terminals at the same time.
It is paramount to make sure that you disconnect first in a car battery, mechanical or electrical parts in some cases may represent a hazard. An impact due to mishandling of cables or electrical devices can seriously affect the driver or damage a component linked to the system. In any case, if you still have doubts, consult the owner’s manual or seek the advice of an expert. A dirty battery can generate a weak current between the + terminals and the battery retention bracket, leading to hidden current flow.
Finally when disconnecting the battery cables, you must disconnect the negative side first and then the positive. To connect the battery you must do it in the reverse order, positive and then negative.