Main Fuse Breaker Keeps Tripping? 8 Reasons For this

Amongst these are:

• Ground or Earth Fault
• Overloaded Circuit
• Appliance Faults / Faulty Appliance
• Environmental Factors 
• Issues with the Incoming Supply
• Short Circuit
• Electrical Faults or Electrical Issues
• Faulty Trip Switch
• Ground or Earth Fault

1) What do we mean by a ground fault or earth fault?

When there is a connection to Earth by one of the Live conductors of the circuit. That is, Line (Hot) or Neutral have a connection to Earth which is causing electrical current to leak away from the circuit resulting in a device in the fuse box / consumer unit / electrical panel tripping. 

When there is ground fault, depending upon the severity, one or more trip switches in the mains electric box will decide to trip. Under these circumstance the RCD/RCB/GFCI will generally trip. To learn more about this device read our article. 

2) Overloaded Circuit

An electrical circuit is a dedicated cable and trip switch that controls a specific part of the electrical installation in your home. One example of an electrical circuit could be plug sockets. The circuit would normally consist solely of a trip switch, cable, and several plug sockets. It would not be normal for the plug sockets circuit to also control the lights in the property for example. It would be a dedicated circuit for some or all of the plug sockets. 

When we overload an electrical circuit, we ask too much of the wiring and trip switch. Electrical circuits are carefully designed by electricians when they carry out the initial wiring or re-wiring of a property. The design stage considers the intended use of the electrical circuit and plans for a certain amount of anticipated electrical load. 

When designing an electrical circuit for plug sockets, a certain amount of electrical load will be expected from various appliances. When too many appliances are used at once, the design of the circuit is exceeded and the circuit breaker will trip until the electrical loads are removed.

3) Appliance Faults

When electrical appliances go faulty, a few electrical problems can occur within the appliance resulting in a trip switch activating and turning the electrical circuit off. If Line touches Neutral, Line touches earth or neutral touches earth then these unwanted connections can cause a trip switch to activate or a fuse to blow in the plug top of the appliance. 

As appliances age, the internal wiring can degrade forming microscopic cracks in the insulation that surround the copper wiring. These microscopic cracks can allow electrical current to ‘leak’ away from the appliance. 

Internal components in the appliance can fail. Where appliances contain or use water, electrics can become wet causing shorting out or earth faults within the appliance. Normally an appliance engineer is needed to rectify a fault within a faulty electrical appliance. 

An Immersion Heater that has gone faulty is one of the common reasons that a circuit breaker keeps tripping. Its worth trying to turn off the single circuit for this if you have one and see if the power trips once you have done this. 

4) Environmental Factors

Every electrical system is at the mercy of the elements or outside influences. Water is a common cause of trip switches activating. Whenever water enters an electrical system, it can bridge wiring causing shorting out, current leakage to earth or complete and total failure of the affected electrical accessory or cable in which it has penetrated. 

Rodents are a common cause of cable damage a tripped circuit breaker. They chew on the cables and destroy the outer sheath and internal insulation of the cables causing havoc in the process. Where rodent damage has occurred, the pest problem needs to be taken care of before repairs are carried out as new wiring is likely to be damaged in exactly the same way rather quickly if the rodents are still around. 

5) Issues with the incoming supply

Where there are issues in the street or incoming equipment that supplies the electrical system, there are occasionally switches that will trip as a result. Loose connections external to the homes electrical system can cause a GFCI/RCD/RCCB to trip in the electrical system inside the property. This can cause a great deal of confusion to homeowners and occasionally electricians in trying to find the issue. 

These kinds of supply issues sometimes display as intermittent power cuts and may or may not cause the system in your home to trip. 

A Qualified Electrician that specialises in fault finding and emergencies will be best placed to identify the source of the problem.

6) Short Circuit

A short circuit is a situation where the normal electrical resistance that is expected between Line and Neutral is not present. During normal operating conditions, the flow of electricity passed along the Line conductor of the circuit and into an appliance. When the electrical current has passed through the appliance it then flows down the neutral conductor. The size of the electrical current is limited due to the resistance provided by the appliance or electrical equipment through which it flows. 

When there is no resistance and Line is allowed to touch Neutral directly then there is a massive electrical current that flows and this will normally cause a circuit breaker to trip. 

This kind of issue usually occurs when a nail goes through a cable or an appliance goes faulty and is normally equipped with a bang as a fuse or trip switch disposes of the large fault current that has occurred. 

7) Electrical Faults

Various electrical faults can cause switches to trip. There can be a whole host of hidden defects in wiring systems (especially older wiring systems) that can mean a circuit breaker or other trip switch will activate. 

Crossed wires, damaged cables, overloaded wiring, water ingress, incorrectly wired circuits or electrical equipment, faulty sockets, faulty switches and more can cause trip switches to operate. Many electrical faults are not what they seem and will require the services of an electrician to attend and ascertain the cause. 

8) Faulty Trip Switch

Very occasionally a trip switch itself can go faulty and result in unwanted tripping. These circumstances tend to arise after a switch has been tripped and been reset many times resulting in complete failure. In these circumstances there is usually the matter of the faulty switch to replace AND the initial electrical fault to rectify before the matter can be concluded. 

Certain trip switches can become weak with age and trip before they are due to trip. Circuit breakers should allow the rated electrical current to safely flow throughout the circuit under normal operating conditions. When circuit breakers become old or suffer excessive wear and tear, they may begin to trip before they are actually supposed to. A typical 32-amp circuit breaker may begin to trip with say 20 amps of electrical current rather than the rated 32-amp figure. 

9) IF your main fuse keeps tripping with nothing plugged in or connected then try this….

https://www.electricalfaultsfixed.co.uk/blog/fuse-box-tripping-nothing-plugged

10) Common Questions

10.1) How do you fix a circuit breaker that keeps tripping?

You first need to establish if it is the breaker that is faulty or if there is another reason for the breaker tripping. One of the best things to do is to unplug all the equipment in your home and then check if the breaker resets. If the breaker does reset then it is possible that there is some faulty equipment causing the problem. 

If the breaker does not reset then it will be necessary to contract the services of an electrical fault-finding electrician to investigate the problem for you. 

10.2) Should I be worried if my breaker keeps tripping?

Generally, YES. Circuit breakers and trip switches are designed to trip when there is a problem on the electrical circuit. Ignoring the problem and continually resetting the trip switch is going to result in a broken trip switch AT BEST and electrical fires and endless damage AT WORST.

If a breaker is tripping then there is something wrong that needs checking out. 

10.3) How many times can a breaker trip before it goes bad?

There is not set number of times that a circuit breaker can trip before it goes bad. There are various issues to consider when asking this question such as:

• How large is the electrical fault current that causes the trip?
• How close to the safe breaking current is the fault current?
• How old is the circuit breaker?
• What are the installation conditions of the breaker and consumer unit?

These and other factors come into play when considering the average lifespan of a circuit breaker not to mention difference in manufacturing quality and processes between various circuit breaker brands. 

A breaker could trip only once and be completely destroyed if it is disposing of a fault current above its rated breaking current. 

A breaker could trip 20 times and be fine if little stress was caused during the process due to small overloads for example.

10.4) Is it ok to reset a tripped breaker?

It is generally ok to reset a tripped breaker ONCE. Resetting it more than this runs the risk of permanent damage to not only the breaker but the electrical circuit which it protects including cables and electrical accessories. 

Whilst a tripped breaker can be hugely inconvenient, it is worth carrying out some investigation and perhaps consulting an electrician to check what is causing the tripping and what is required to fix it.

11) What is the average life of a circuit breaker?

Without any tripping, most electrical circuit breakers seem to last in excess of 25 years. We regularly see equipment of this age and older that is still in service. Beyond this age it is likely that internal corrosion has taken place on the metals that form the circuit breaker innards. When this occurs, there is likely to be higher than normal resistances internally, poor contact and the likelihood that the circuit breaker may not operate or perform as the manufacturer intended. 

12) Can I replace a circuit breaker myself?

Whilst there are many ‘how to’ videos out there on the internet, replacing a circuit breaker is not something that we would recommend anyone other than an electrician carries out. There are several important steps that need to be carried out correctly in order to ensure that the work complies with BS7671 including:

• The compatibility of the equipment
• The torque settings
• Safe Isolation Procedures using equipment to GS38
• Testing and Certification procedures in accordance with BS7671
• Visual checks following the replacement

There is a common misconception that electrics are ‘easy ’ or ‘it’s just three wires’ and unfortunately this is not the case. The current regulations are in excess of 560 pages long and lay out what is required in order to carry out electrical work safely. No-one other than an electrician will have the required knowledge to do this correctly. The most important thing is peace of mind and safety and an experienced electrician will carry out electrical wiring to the required standard and certify the work where required. 

13) What to do if an appliance keeps tripping the breaker?

If ONE appliance keeps tripping the breaker causing a loss of power, then disconnect the appliance from the wall outlet and do not use it until it has been checked by an appliance engineer. Check that it IS IN FACT that specific appliance and not the socket outlet by using another appliance in the same plug socket and seeing if the problem occurs again. You could also try the appliance in different electrical outlets to see if that makes a difference. 

If it definitely is the appliance then have it checked.