Electrical Fault-Finding Steps to Identify Faults

July 2024

An electrical system will operate in a seemingly normal manner right up until the point of complete failure. Electrical problems can go unnoticed by homeowners until a symptom appears to warn of the electrical issues that are lurking. 

1) What is an Electrical Fault?

An electrical fault can be defined as an issue that prevents the electrical system from operating in the manner in which it was designed and installed to. Such faults can be serious electrical issues like the risk of electric shock, or more minor inconveniences such as a faulty appliance or light bulbs that flicker. 

Issues that appear to be minor can actually be a symptom of something more problematic beneath the surface so its always important to check them out as soon as possible.

2) What types of electrical faults are there?

There are various issues that can occur within an electrical system meaning an almost unlimited number of electrical faults can occur. The most common are:

• Short Circuit
• Earth Fault
• Loose Connection
• Cable Insulation Breakdown
• Faulty Circuit Breaker
• GFCI or RCD issues
• Complete Power Loss

Within these particular faults, there can be a whole host of reasons for the cause but we will cover the typical issues that can cause each in this article. 

3) Short Circuit

The short circuit is a situation where Line (HOT) and Neutral have somehow managed to become connected to each other. When this occurs, there is very little electrical resistance to electrical current flow and as such power surges can occur and large fault currents can develop. 

The result of this is, that without quick action by the consumer unit, electrical panel or fuse box, there is likely to be severe overheating of the electrical system and electrical fires as electrical wiring overheats and struggles to cope with the massive current flowing through it. 

Causes: A nail through a cable, electrical appliances with faults, damaged wiring, loose connections in junctions and other accidental damage. 

Fixes: Great care should be taken when attempting to correct or locate an electrical fault. Try to remember if any recent work has been carried out in the home, even things as small as hanging a picture on the wall could have resulted in a nail through a cable.

Unplug appliances before resetting a breaker. This will rule out a faulty appliance problem. If the GFCI or RCD still trip then a professional electrician will need to be called to carry out some fault finding.

4) Earth Fault

An earth fault occurs when there is an unintended path to earth from somewhere on the electrical circuit. This could be an accidental connection from Line (HOT) to earth or Neutral to earth. 

With a Ground-Fault circuit Interrupter (GFCI) or Residual Current Device (RCD), there does not have to be a great deal of electrical current making its way to earth for the device to trip. These devices are designed to protect us from electrical shocks so they have to be incredibly sensitive in order to protect us adequately. 

Where an RCD or GFCI is tripping, do not continually reset the breaker as this may result in the device breaking, other electrical damage occurring and the risk of electrical shock increasing as there is now much less protection.

Causes: Again, there can be numerous causes for this device to trip. Cable damage, faulty wiring, water ingress into outdoor equipment such as security lights and appliance faults can all cause a GFCI or RCD to trip off continually or intermittently. 

Fixes: Before resetting a circuit breaker, RCD or GFCI device, check that all electrical appliances have been unplugged from the wall in the property. Once this has been done, try resetting the breaker. Careless DIY can also result in cable damage hidden in the walls so think back to remember if any works have been carried out recently. 

5) Loose Connection

A loose connection can be a risk to the entire house. Loose wires cause fires. Where wiring has not been inspected by a qualified electrician for a long time (>10 years) things can work loose. 

Wiring that was never correctly torqued (tightened up) in the first place is particularly at risk. Connections that were made too tight are also at risk strangely. 

Causes: Wiring works loose due to the continued expansion and contraction of various metals. Sockets, switches, and other electrical accessories have metal terminals and, along with the metal wiring in our homes, expansion and contraction occurs at different rates and in varying amounts depending upon how much electrical current is flowing through the electrical wiring. 
Along with the tiny vibrations from supply frequency in our mains wiring, the connections can loosen over time. 

Fixes: An electrician should come to check the connections to ensure that they are adequately tightened and safe. If you have recently carried out any electrical work, re-check the connections to ensure that they are adequately tightened. If in any doubt, consult a professional for electrical work.

6) Cable Insulation Breakdown

Around the wiring in our homes, there is an insulating layer of flexible PVC. Over time, this can become brittle and micro cracks can develop in the insulation. This is accelerated where cables have been subjected to extensive heavy loads or prolonged use. 

The last cables to fail in an electrical system are usually the cables that supply the lighting circuit. The lighting circuit tends to have the easiest time in most domestic wiring systems as it supplies absolutely minimal electrical current. 

Causes: Age of wiring, abuse, excessive loads, homes with only a few circuits that are heavily used. 

Fixes: An electrical inspection is recommended to determine the condition of the wiring system and its suitability for continued use. Possible rewires may be needed if electrical test results come back with poor readings. 

7) Faulty Circuit Breaker

There are a variety of trip switches in our electrical panels, consumer units and fuse boards. They each have a specific purpose and without them, our electrical system would be unable to function safely. 

The purpose of each trip switch is to protect against electrical faults and the circuit breaker is there to prevent excessive electrical current from flowing through the wiring and causing damage. 

Causes: Too many appliances being used at the same time, damage to wiring, short circuits (see above) and in some cases the circuit breaker may itself be faulty. 

Fixes: Try unplugging all appliances, leave the circuit breaker off for a few minutes and then attempt to reset once. It may trip off or blow off again. Do not reset this device more than once. The breaker is tripping because there is an electrical fault and serious damage can occur if it is continually reset. Call a licensed electrician immediately to investigate the cause of the problem for you. 

8) GFCI or RCD Issues

These devices are life saving devices and should be tested regularly by a qualified professional. There is a self-test that you can do which is not as thorough, but does at least let you know that the device is operational.

When these devices trip, there is a definite risk of electrical shock occurring so they shut of the power supply to the electrical equipment on the part of the electrical installations that they protect. Some consumer units, electrical panels and fuse boxes have a “Main Switch” RCD or GFCI device that protects the whole installation.  

An upfront switch tripping, is not ideal as the whole installation will experience power loss at the same time. They are however, better than not having an RCD or GFCI at all. 

Causes: Water ingress, rodent cable damage, faulty wiring, faulty appliances and loose connections.

Fixes: Firstly, unplug everything from the wall, switch off all wall switches and attempt to reset the device. If the device does not reset then call an electrician to carry out some electrical testing for you. 

9) Complete Power Loss

Where complete power loss occurs, double check that the lighting circuits are also affected. Some consumer units will allow power to disrupt to everything but the lighting. 

If there is indeed a complete power loss the first thing to do would be to call your local electric company that supplies your home to see if there are any emergency works being carried out locally or other homes affected. 

If you are in the United Kingdom this can normally be achieved by dialling 105 freephone to speak with the local network operator for your area. 

Causes: Complete power loss is an electrical emergency and can be caused by a tripping, burnt out or failing main switch, a blown fuse on the incoming supply, a loose neutral connection in the main electrical panel or fuse board and in some cases: supply issues in the street. 

Fixes: There are no safe DIY fixes for this type of electrical fault I’m afraid. Once you have established with the local power company that there are no issues, its definitely a job for a professional. Checking electrical connections, the main safety switch and checking for causes of power outages should be left to professionals. 

10) What is an open circuit?

An open circuit is a situation where the circuit has become broken. This can occur when faulty electrical components cause a breaker to trip, cable damage occurs on one of the conductors in the cable or where junction boxes burn out or connections become loose. 

A closed circuit is necessary for electrical current to flow as there is a complete pathway for it to make its way round. 

11) Is old wiring dangerous?

Electrical switches, electrical outlets, home circuits and electrical switchboard (panel, consumer unit or fuse box) are only designed to last so long. Many homes will now have wiring that is outdated, untested and potentially dangerous. 

Old wiring MAY be dangerous but the only way to know for sure is to have your wiring inspected by a professional. The electrical testing that is carried out is of the upmost importance and will reveal a problem circuit, electrical safety concerns and other electrical hazards that need to be rectified. 

Your electrician will give you a report detailing the outcome of the inspection. The report should outline any repair works that are necessary in order to bring the electrical system up to current regulations or up to code. 

Today’s codes are most stringent that decades gone by and older homes with older wiring may not result in a satisfactory outcome on the inspection report. 

12) Summary 

There are many possible electrical faults that can occur. Some are hidden and will never show a symptom until a secondary issue develops and that is why regular electrical inspections are important. 

There are some possible DIY fixes, but these are limited and any interference in the electrical system by unqualified persons can result in a fire hazard, shocks or burns. 

Its important to know when to consult an electrician for professional help and advice, I trust that this article has helped in some way.