Burnt Electrical Box

1) What is an electrical box?

There are a multitude of different names for essentially the same thing. The electrical box in your home can also be known by the following names:

• Consumer Unit
• Electrical Panel
• Fuse Box
• Fuse Board
• Distribution Board
• Trip Switch Box
• Electric Box

Regardless of the name you know this by, the usual term used by electricians to describe this box is the consumer unit. 

2) What does a consumer unit do?

The consumer unit takes the incoming power from the street and divides it into different electrical circuits and sends the electrical supply around your home. It is the brains and control centre of your electrical installation and absolutely vital to the safe operation of your home electrical system. This consumer unit is designed and installed by a qualified electrician to ensure that the cables in your home are protected and that you are protected adequately against electric shock in combination with other protective measures. 

3) What causes the consumer unit/electrical box to become burnt?

Sometimes these consumer units can have problems and overheat causing a BURNT ELECTRICAL BOX /consumer unit. When this happens there can be varying levels of damage. There can be several causes of this and we can determine these causes when we attend your home to make safe and repair the problems. 

There are devices in the consumer unit that generate heat during normal operation and this is fine. These devices are designed to dissipate the heat that they generate, and in cases where all the components are the same brand, the heat will be dissipated correctly and safely. Problems occur when components of different manufacturers are mixed together.

These components can cause mechanical stress, strain and therefore excessive electrical resistance and heat generation if they are not compatible with the original manufacturers’ equipment. It is not enough for the components to be of different brands but the same dimensions either. Components can be different inside but have the same size outer cases. 

These components will heat up on a specific side and dissipate any explosive forces from electrical faults in a particular way, mixing these components is never a good idea!

4) Are there any other ways that these problems can occur?

Yes, when electrical connections are too loose or too tight there can be big problems. Each manufacturer will have a recommended torque setting for their devices and these should be adhered to. What tends to happen over time to electrical components is that the screw terminals can become loose. 

Heating and cooling of metal as power is drawn through cables and components can cause screws to loosen. This, combined with the frequency of our supply in the UK which causes a slight vibration on the cables can mean that wiring can become dangerously loose within a short space of time. This is one of the reasons why a regular (every 10 years) electrical inspection is recommended. 

5) How does a loose connection cause burning?

When there is a loose electrical connection there is a high resistance joint. That means that the electrical current cannot flow through the circuit easily which creates heat. Guess what? Heat also creates a high resistance situation; the hotter electrical wiring gets the higher its resistance becomes which further adds to the problem and very quickly loose connections can get hot and become a fire risk! 

The photo above shows an issue which has caused a burnt switch and could easily have led to a BURNT ELECTRICAL BOX  / consumer unit had we not intervened at this stage. Despite the problems we found, the electrical installation was still functioning and the customer had not noticed any problems. This issue was hidden inside the consumer unit. 

We can see that the main wire feeding this switch is burnt black and the insulation has bubbled. This has damaged the switch and requires repair. 

6) What else can cause a burnt electrical box?

When a circuit is overloaded and not designed correctly, we can see problems inside the electrical box with the circuit breakers. Circuit breakers are the trip switches that you see inside your electrical box. These are designed to turn off the power to the sockets, lights, cooker and so on when there is an overload of current or a fault on the circuit.

The problem is that nothing is designed perfectly and these circuit breakers can sometimes overheat under the right conditions. It is rare but can happen. When electrical components inside the consumer unit get too hot, they can cause burning and a risk to the other components and wiring inside the box. 

7) Can we do anything to avoid problems like this?

There are a few things that can be done to avoid potential problems like this:

• Check the Panel / Consumer Unit for Damage
• Have an old Panel / Consumer Unit Replaced
• Have Wiring Repairs Carried Out Promptly
• Have an Electrical Inspection Carried Out

8) Check the Panel / Consumer Unit

You should regularly visually inspect your consumer unit or electrical panel for any damage, holes, signs of overheating or other issues. 

Damage could include things like cracking to any surface of the consumer unit, lid or flip down cover missing from the unit. Any switches that are broken or have visible signs of damage are also something that needs to be rectified. 

Holes in the panel are also generally not good as this could give access to live parts using fingers or objects. Any holes should be properly sealed up by an electrician using the correct equipment or products. 

When checking for overheating on electrical panels or consumer units, you are looking for discoloration such as yellowing, browning or blackening, signs of melting such as disfiguration in plastic consumer units and any sooting anywhere around the unit. 

Cables that enter the consumer unit or electrical panel should enter without touching bare metal edges and leaving no gaps where a finger could be inserted as a general rule. 

9) Get the Old Stuff Upgraded

Sometimes the “We have never had a problem before” outlook to electrics is not the best outlook. The chances are, if you are living with an aging wiring system, an old fuse box or electrical panel then you are going to experience serious electrical issues in the near future. 

Get your old wiring replaced if it is clearly ancient, have the consumer unit / electrical panel upgraded by an electrician who will also perform some safety checks whilst they are there swapping the panel. 

Newer consumer units will detect many more electrical faults, dangerous situations and offer much more protection against electric shock than older panels so they are a vital safety upgrade to the home. 

10) Sort out those Wiring Repairs

The dead socket outlets, flickering lights or intermittent tripping switches are all signs that there are wiring repairs that need to be carried out and electrical faults that need to be investigated. These issues do not generally resolve themselves and will nearly always get worse rather than better! 

I have lost count of the times I have turned up to an electrical emergency at a clients home to find that the problems have been recurring over several months with absolutely no action on their part until total system failure has occurred and expensive repairs have now become the only way to resolve the issue. 

11) What about Electrical Inspection?

An electrical inspection is a thorough process that takes several hours if done correctly (check how long this will take with your contractor before booking) and will highlight minor, major and downright deadly issues if there are any. 

An inspection every 10 years can pick up on issues that are not currently serious but will be if left. You are highly unlikely to have any issues in a new home for at least 10 years unless the installation is modified and not tested during works. 

The important point I tell my clients is that you must find an electrician that you trust, perhaps someone that your family has used and trust or someone with really great Google reviews. Ask that electrician to come and perform the inspection for you and run through any issues in PLAIN ENGLISH with you. 

Have any electrical work carried out correctly and ensure that you are given the necessary paperwork for any work carried out. Nearly every electrical job requires a certificate to conform with the wiring regulations and to ensure your safety and peace of mind. 

If you are unsure of the condition of your homes electrical system and would like it inspected then feel free to give us a call.