How To Identify a Short Circuit in a Circuit Diagram?

Source

Electric circuits are the paths that the electrical particles or the electrons pass through, known as the current. The electrical circuit has many components such as conductors, resistors, power sources, etc.; circuits have three types: short, open, and closed circuits. So, how to identify a short circuit in a circuit diagram?

How To Identify a Short Circuit in a Circuit Diagram?

To identify a short circuit in a circuit diagram, you have to look for a wire with less resistance or no resistance connected around a resistor. If you find a wire like that, you have a short circuit resistor because there is no current flowing through it. For example, if you have a circuit consisting of a light bulb. 

The light bulb is connected to a power source; it will work fine until you connect a wire with very less resistance or no resistance in parallel with the bulb. Then, the current generated from the power source will not pass through the resistor and choose the path with no resistance; therefore, the bulb will be shorted and not work.

How To Identify a Short Circuit With a Multimeter?

  1. Locating The Short Circuit
    When locating a short circuit, you need to look for physical signs; melted metals on wires, burning odors, visible burns, or flashing lights. Once you have located the short circuit, you need to use your multimeter to confirm it by using continuity or resistance mode in the multimeter. If you found a lower resistance than you expected, this is your first indication that there’s a short circuit condition.
  2. Confirm By Using The Multimeter
    After locating the short circuit, you need to confirm it using the multimeter, but before starting to test the circuit, you need to disconnect it from the power source by turning off the circuit’s breaker. Adjust your multimeter again, change it from resistance mode to AC volts mode, and then use the multimeter’s probes to check the faulty device or switch by connecting them to the probes. The multimeter reading should be zero volts because the circuit should have no power since you turned off the breaker. 
    However, if the multimeter shows a reading other than zero, you need to check the circuit’s breaker again and make sure that there is no current leaking to the circuit and responsible for this power.
  3. Check The Wires
    After making sure there’s no power in the circuit, which is a very important step to ensure that you are safe when testing the wires. Adjust your multimeter again, change from AC volts to ohm, and check the wires. If the multimeter’s reading is OL or infinity ohms, you could have a bad breaker that can be tripped from a lower current, and you need to replace it from the main panel.
    Meanwhile, if the multimeter reads a continuity, you have a short circuit which can be caused by a bad switch, broken wire, or a bad breaker. You need to need the cause and fix it or replace the bad component, If there is a continuity still, you may have a bare wire, and you need to insulate properly. 

What Are The Dangers of Short Circuits?

The main danger of short circuits is the heavy load put on the new path, which generates heat and increases the temperature of the wire, and can lead to the melting down of its insulation. When the insulation melts down, this can lead to many consequences, for example:

  • The Emission of Danger Chemicals From Cells and Batteries.
  • An Explosion.
  • Fire Hazards.

Another danger of short circuits is shocks and injuries; when there is a short circuit, the current can search for a short path, such as the human body. If anybody is close to or near a circuit that has a short circuit problem and touches it accidentally or unintentionally, the current can pass through his body.

What Are The Causes of Short Circuit?

Short circuits can have several causes, such as bad wires insulation; you can prevent the causes of short circuits by knowing and countering them. Many different causes can lead to a short circuit problem, but the most common ones are:

  1. Bad Circuit Wire Insulation:
    When the wire’s insulation is damaged and old, it can let the neutral and live wires touch, which leads to a short circuit problem. Torn and worn-out wires and non-insulated screws, nails, and staples can be another cause of short circuits. Wires can get bad and damaged for many reasons; for example, animals like rats and mice can damage wires when they chew them; they make the wires get exposed and damage their insulation, leading to short circuit conditions.
  2. Bad Appliance Wiring:
    Bad appliance wiring is another reason for short circuit problems; old appliances and devices can have short circuit problems within their wiring, power cord, or plug. When the appliance is connected through its cord or plug, the short circuit is active, affecting the circuit they are connected to because they are considered an extension for the circuit.
  3. Loose Wires’ Connections: 
    When the wires’ connections get loose, the neutral and live wires can touch and cause the current to pass through an unintended path, which causes short circuits.

What Is The Difference Between Short, Open, and Closed Circuits?

Closed Circuit  Open Circuit   Short Circuit
Wires’ Connection   Connected Internally.  Connected Externally.  Connected Externally.
Current Flow  Current passes in a loop. The current doesn’t flow. The current doesn’t flow.
Resistance   Resistance is zero. Resistance is infinity. Resistance is infinity.

Open Circuits 

Open circuits are the circuit where there is no current flowing through; the current can flow if there is any break or incomplete path in the circuit; the current doesn’t flow and stops where there is a break; the current is not generated. So you can find current passing through only in closed circuits.

Therefore, if you have no current, you have an open circuit; the terminals of open circuits are disconnected, so there is no continuity in the circuit, which makes there is no current; however, in an open circuit, there is a voltage drop between the two terminal of the circuit. Therefore, open circuits have infinity resistance because they have zero current. 

Closed Circuits

You can imagine a closed circuit as the bridge over the water; the bridge allows you to pass from one side to the other, then you can go back to the other side again. It’s the same case for a closed electrical circuit, which allows the movement of electrons or electrical particles from one side to the other one.

The closed circuits have no interruption that stops the flow of the power; the current passes from one side to the other because the circuit is complete and has no breaks, and this happens when the switch is turned on “closed,” which completes the circuit, so the current start flowing. 

Related Readings:

How To Tell if a Resistor Is Burnt Out? And How To…

Why Do Parallel Resistors Have Less Resistance?

Why Is the Voltage in Parallel Resistors the Same? Answered

How To Measure and Identify Resistor Using…

What Happens if You Switch Neutral And Ground Wires?

Why Voltage Decreases When Current Increases?

What Does a Short Circuit Mean?

Short circuits are electrical circuits where the current passes between two unintended points; this path has no or very low resistance. For example, if the current path chooses to flow through a parallel path to a resistor or a device, the device will get shorted, so there will be no current passing to the device.

A new path is created when two points in an electrical are connected accidentally or unintentionally. Therefore, they create a path with very low resistance or no resistance, making the current prefer to pass through it and leave its main path. However, the main problem with short circuits is not the devices not working.

The new connection that is created sometimes can not tolerate the amount of energy flowing through it, resulting in a heavy load on the new path, which can raise its temperature. In addition, the heat generated from the load can lead to the melting down of the insulation of the wires and affect other surrounding components.

Source

Conclusion

To sum up, you can identify a short circuit in a circuit diagram by looking for a wire with less resistance or no resistance connected around a resistor. If you find a wire like that, you have a short circuit resistor because there is no current flowing through it.

For example, if you have a light bulb circuit connected to a power source, it will work fine until you connect a wire with very less resistance or no resistance in parallel with the bulb. In addition, you can identify a short circuit using a multimeter, but you have to locate it first.

When locating a short circuit, you need to look for physical signs; melted metals on wires, burning odors, visible burns, or flashing lights. After locating the short circuit, you need to confirm it using the multimeter, but before testing the circuit, you need to disconnect it from the power source.

Scroll to Top