5 Reasons for circuit breaker tripping. What should you do?

5 Reasons for circuit breaker tripping. What should you do?
circuit breaker tripping

Circuit Breaker Tripping. Why?

Before we discuss the circuit breaker tripping let’s define Circuit breakers. In our previous article, we discussed different types of overcurrent protection devices. A circuit breaker is one of the protective devices having a switch on and off button. It is designed for the purpose to limit the flow of a large amount of electrical current from electrical devices.

Do you notice that some time light of a residential place goes off due to circuit breaker tripping or sometimes the fuse blows up? It is due to some faults in the electrical network. We are listing different reasons that cause circuit breaker tripping for electrical engineers, electricians and for you in your home.

Reasons for Circuit Breaker tripping

In this article, we are discussing different reasons that cause circuit breaker tripping. We will start discussing for non technical persons. Like you in your home or workshop.

1-Circuit breaker tripping for non tech. persons.

A circuit breaker is a device with one job, Protecting you and your house against electrical hazard. As you know electrical devices are around us in our homes. These devices draws electrical current with a designed value. Circuit breakers at homes are called MCBs (its a technical name, don’t worry about it) each MCB has a current value which it can handle without tripping. But when the value of current passing through this CB exceed its rated value then it will trip for safety reasons.

We know that CB trips due to high current value. But what causes the current to be high? As mentioned above. Each electrical device draws a designed current value in normal operation conditions. But if the device it self has an internal issue, it will draw more and more current. This current is enough to make MCB to trip.

Now we discussed the causes which makes CB trips. What should you do as non technical person when your CB trips at home?

  1. Switch off all devices and unplug all possible electrical devices which are affected by tripped circuit breaker.
  2. Go to your electricity box and search for the CBs which are on the off position. A red or orange label may indicate the status of trip on the CB. Turn it on carefully. (If breaker keeps tripping while all loads are off and unplugged, then the breaker should be replaced).
  3. Turn on all devices one by one. If all devices turned on and no breaker tripped again its ok. If breaker keeps tripping, then you should call electrical service to check and inspect all devices to detect the issue and decide how to solve it.

Its better for your own safety to hire an electrician to replace the damaged breaker.

Now after this quick discussion for non technical persons. let’s move to electrical engineering discussion.

1-Overloaded Circuit

One of the main reasons for circuit breaker tripping is the overloaded circuit in the electrical system. We studied in our previous articles that the circuit breaker is always rated for a specific voltage and current. When a large number of loads are connected with the circuit, the circuit attempts to draw a greater electrical load than its rated value. Due to which the circuit breaker heats up, and the breaker tripping occurs. After tripping the circuit remains dead until someone reset the breaker lever to the ON position. 

Never overload electrical circuits
Never overload electrical circuits

2-Electrical Short Circuit

Another reason for the breaker tripping is the electrical short circuit. Defining a short circuit is necessary for our viewers. A short circuit occurs due to low resistance. In the Electrical phenomenon when the positive and negative terminal connects with each other in the absence of any resistance. This causes an unimpeded flow of electricity. And a large amount of current flows through a broker that causes tripping.

It is worth mentioning here that how to decide whether the tripping occurs due to a short circuit? The answer is clear and simple. If a circuit breaker trips instantly again and again after you reset.The tripping occurs due to a short circuit.

Short circuit types

  • In DC circuits When positive cable directly contact with the negative one this is a DC short circuit.
  • In AC circuits:
  1. Phase to phase AC short circuit is when two different phases connected to each others directly. This is the most dangerous type of the all 3 types. Its short circuit current is the largest.
  2. Phase to ground short circuit happens when one phase contacts ground cable. Its also called ground fault.
  3. Phase to neutral happens when one phase and the neutral contact each other directly.

3-Ground Fault

Another reason that causes the circuit breaker tripping is the ground fault. A ground fault is a type of short circuit when a hot wire came in contact with the ground or any other type of metal. The ground fault causes an increase in the flow of current. The increase in the flow of current is due to low resistance. It causes the circuit breaker to heats up and as a result, circuit breaker tripping occurs.

Some ground faults are not detectable by normal MCB. SO its recommended to use GFCI (ground fault circuit interrupter) This is better for human safety as this breaker can detect small milli-amperes and trips before a shock happens.

GFCI - ground fault circuit interrupter
GFCI – ground fault circuit interrupter

4-Arc Fault

When fluctuation or sparking occurs between two-wire connections at a point. Arc faults occur. Sometimes the screws at a point become loose, In this case AFCI (arc fault circuit interrupter) is recommended. While the circuit breaker is an Arc fault interpreter (AFCI ). It detects the early wiring problem and trips in advance to stop the flow of a large amount of current.So sometimes the circuit breaker tripping occurs due to arc fault.

5-Reason five is the CB it self

Some times the circuit and loads are all ok and in a good condition. But the breaker keeps tripping. This is because it is damaged. Like any devise, breakers has life time and then breakers go bad. And need replacement.