La boîte de disjoncteur de l'unité grand public fait un bruit de bourdonnement

March 2024

1) What are the Causes for a Fuse box Buzzing Noise?

There are numerous possible causes for a FUSEBOX BUZZING NOISE. Sometimes a buzzing noise is not a big issue and there is no reason for alarm but under some circumstances there could be a serious problem that required professional intervention.%20

• Doorbell Transformer
• Loose Connections in Fuse Box / Consumer Unit
• Issues with Electric Meter%20
• Issues with incoming Mains
• Failing components in Fuse Box / Consumer Unit%20

2) Doorbell Transformer

Strange electrical noises can come from all sorts of electrical components and the doorbell transformer is no exception. Most home doorbells are lower voltage than the mains and require a transformer to step-down the voltage to a lower voltage than the mains supply.%20

These transformers are very efficient and not much energy is wasted when the voltage is changed to a lower one. Any energy that is wasted is used as heat and sound. The sound tends to be a low hum type noise which, is particularly prevalent especially with older doorbell transformers.%20

If you listen closely, you may be able to pinpoint the exact location of the buzzing and if it is the transformer then a low hum could be completely normal. A loud buzzing sound can indicate that there are problems however, if there is a particularly loud sound coming from yours then have a local electrician check it out for you.%20

3) Loose Connections in Fuse Box

Loose connections are a serious problem and can cause fired if left unchecked. One of the first noticeable signs of loose connections is flickering lights which should never be ignored. The next noticeable sign is a burning smell, buzzing or crackling sound from the fuse box. Any loud bang from the fuse box should never be ignored, even if it doesn’t happen again as this is another serious sign that there are electrical problems.%20

Over time, wiring connections can become loose as metals heat up and cool down, vibrations on the mains supply wiggle things loose slowly and screws work loose. These combined effects can speed up loose wires resulting in connections that fail after a few years especially if they were never torqued correctly to begin with.%20

4) Issues with Electric Meter

One of the main things that can happen with an electric meter is the mains cables working loose like we can see in this photo:

This has resulted in LIVE copper being on show and able to be touched but ALSO loose connections which would have no doubt resulted in burning wires and possible fire had this not been found.%20

Inside older electric meter there are components that move and can vibrate. There are internal connections that can work loose and cause buzzing noises as electricity generates heat and struggles to pass. When this becomes serious there can be crackling noises also as electric tries to jump an air gap through a poor connection.%20

One thing is for sure, if you have strange noises coming from your electric meter then you should call your electricity supplier to ask them to check it out for you. The electric meter is generally the responsibility of the company that you pay your electric bills to.%20

5) Issues with Incoming Mains

Before the electric meter and electrical panel there is the incoming mains equipment. This is often a black or grey box about 6 inches square in size with a large black cable entering the bottom and two smaller cables exiting the top.%20

The top cables are either both grey, blue brown or red black in colour. This box contains a fuse which prevents the incoming mains supply cables from overloading and catching fire or shorting out and exploding.%20

Electrical issues can often begin here with a loose connection or loose wire. A sizzling noise emanating from this box is a very bad sign and needs to be checked immediately. The company responsible for this incoming equipment can be reached on 105 freephone. Explain the problem to them and they should attend very quickly.%20

6) Failing Components with Fuse Box

The warning signs of a failing component such as a circuit breaker, main switch or RCD in a circuit breaker box are:

• Intermittent tripping%20
• Electrical panel smells of fish or plastic
• Faint electrical buzzing sound
• Intermittent power cuts
• Flickering of lights
• Power outlets cut out sometimes

(Photo: Burnt Out Main Switch)

Any of these above signs could be caused by loose wiring on the Main Switch for the electrical system. This is a serious fire hazard as you can see! There are often no warning signs that will be noticed by anyone before it gets to this stage. Most times, as emergency electricians, we are only called when there is a complete and total power loss to the property by then, the damage is often done.%20

6.1) Intermittent Tripping

Whilst there are a number of causes for intermittent tripping of a GFCI, RCD, RCCB or other switches in the circuit breaker panel, one of the causes can be loose wiring. The FUSEBOX BUZZING NOISE is often just one of the other warning signs.%20

6.2) Electrical panel smells of fish

As electrical current flows through an electrical panel there is a certain amount of heat generated proportionate to the size of the current and the resistance that is experienced by that electrical current.%20

The size of the electrical current is down to the demand from the electrical system with electric showers, plug sockets and car charging equipment being the most power hungry. The resistance is something that we aim to keep as small as possible, after all, we want the current to flow freely.%20

When burning begins due to loose-connections, high resistance or other means the heat increases. As the heat increases the resistance to current flow also increases creating a no-win situation and an inevitable small fire will occur.%20

This smouldering or burning of electrical PVC and plastics smells like fish funnily enough. The chemicals given off are very pungent and it is certainly not a smell that you will likely forget in a hurry.%20

6.3) Faint Electrical Buzzing Sound

This could be something benign like a doorbell transformer but it could be a sign of a faulty circuit breaker or something else. Get a professional electrician to check this out for you immediately. An electrical fire in an electric panel can not only lead to lots of electrical work and costly repairs but can also damage other parts of the electrical installation such as the cables that leave the fuse box.%20

If heat travels far enough up the electrical cables, it can ruin the cable insulation meaning partial rewire is necessary in order to put right the installation. Not to mention the risk of damage to the rest of your property.%20

6.4) Intermittent power cuts

These are a sign that things aren’t right. Before thinking the worst, check with your local power company to see if there are any planned or unplanned electrical works in your area. There could be a short circuit or loose cable out in the street underground causing the electrical installation to suffer intermittent outage.%20

If there is nothing going on outside then the problem must be inside. If the issue is intermittent then check to see what appliances you have running at the time of the problems. A faulty appliance or powerful appliance could be exacerbating the issue!

6.5) Power Outlets Cut Out Sometimes

This is a concern. If you have power outlets that cut out occasionally then there is likely a high-resistance connection somewhere. This could be at the consumer unit, the MCB or on the circuit. This can create a FUSEBOX BUZZING NOISE and lead to more serious issues within a short space of time.%20

If you have an old fuse box like the one pictured below then it is time to consider a replacement. These are at BEST 40 years old and likely to be even older. It is strongly advised to have an electrical inspection carried out when your system is this old.

7) Common Questions Answered

7.1) How do you fix a buzzing fuse box?

Whilst there are some fixes that can be carried out with a do-it-yourself approach, interfering with a fuse box is a dangerous matter. This kind or investigation and repair should ONLY be carried out by an electrician.%20

Investigating a bad circuit breaker, electrical wiring or working on wiring systems is a technical and dangerous job fraught with electrical hazard and surrounded by nearly 600 pages of regulations that need to be adhered to.%20

7.2) Can I have a new consumer unit fitted with old wiring?

There are many benefits to having a replacement consumer unit installed over an old fuse box. The up-to-date technology will protect against electric shocks, overload, surges, electrical fire to an extent and in some cases arc faults too!%20

There can be some problems installing a new consumer unit onto old wiring as older fuse boxes may have missed many electrical issues hidden in your wiring system so it’s a good idea to read some more about it before committing. There is a great article we have written here about it.%20

7.3) Can a buzzing circuit breaker be repaired?

A licensed electrician will advise against attempting any repairs on circuit breaker or trip switches. These items are generally not repairable and must be discarded once they have failed. The only sensible repair is to replace them with new circuit breakers. In accordance with regulation 536.4.203, these devices should only be replaced with the original manufacturer’s equipment as well so if you have non branded replacements in your consumer unit then they should ideally be swapped. A faulty MCB may give off an annoying humming noise or even a slight hum. A qualified electrician can check for a slight humming noise and carry out some investigation to find the cause or source of the noise.

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