Tumble Dryer Plug Melted: Why?

1) What causes tumble dryer plug failure?

A tumble dryer is a powerful electrical machine. The tumble dryer has a heating element inside the appliance and as such, it is usually one of the most powerful electrical appliances in the home. When an electrical heating element demands power, it is often a lot of power that is required and as such this places a great demand on the electrical system and the electrical accessories local to the demand. 

This high demand for electrical current is often too much for an aging plug socket to cope with and as a result we can see a burnt outlet, melted plug socket or plug top occurring. Plug sockets and plug tops are not designed to last forever and do occasionally need to be replaced or maintained by an electrician. Tumble dryer plug failure can occur when:

• Loose connections in the plug socket develop
• Loose connections in the plug top of the appliance occur
• Excessive demand is placed upon the plug socket with extra appliances
• Aging plug socket with high internal resistance
• Debris or dirt accumulate in the plug socket
• Incorrect fuse inserted
• High ambient temperatures
• Extended and prolonged appliance use

1.1) Loose connections in the plug socket develop

Loose connections can occur in a plug socket for several reasons. The plug socket may not have been installed correctly to begin with resulting in incorrect torque applied to the terminals that hold the wires at the rear of the plug socket. 

Loose connections can develop over time as the different types of metals expand and contract due to the temperature created by electrical current flow during normal electrical installation use. Along with the supply frequency of the electricity supply the effect of loose connections can accelerate over time. 

1.2) Loose connections in the plug top of the appliance occur

If loose connections occur in the plug top of the appliance, then there can be a lot of heat generated and as a result the plug top can burn out and damage the plug socket with it. If you notice the plug getting warm then there is a good chance that things aren’t quite right. 

Under normal operating circumstances, plug sockets and plug tops may warm up slightly but excessive heat build up is an indication that perhaps there are issues that require investigating. 

Loose connections in a plug top usually occur due to poor installation of the plug top on the appliance cord. Flexible cables used for appliances can suffer badly through poor installation. Flexible cables are notorious for becoming ‘chewed up’ in screw terminals and installation should be carried out carefully to ensure that the full body of the wire is inserted into the terminals correctly and tightened adequately. We discuss the correct installation of a plug top in another article.

1.3) Excessive demand is placed upon the plug socket with extra appliances

Most UK Plug socket outlets are rated to 13 amps which comes as a surprise to many people. A typical washing machine or tumble dryer demands about 10-13 amps on its own during the period of its operating cycle. 

This means that if you have a tumble dryer plugged into a plug socket and another heavy use electrical appliance such as a washing machine, then it is very likely that the plug socket will become overloaded at some point.

This results in overheating and damage to the plug socket and wiring behind. This heat can also travel to the pins on the plug top of the appliance and damage the plug top itself. Care should be taken not to exceed 13 Amps in any plug socket (double socket or single socket) or any extension lead. Please check the rating of your extension lead before use as some are rated lower than 13 Amps. 

It is worth noting that these types of overheating electrical faults will not trip a circuit breaker in an electrical panel or fuse box. Many socket outlets are also not designed to trip nor do they generally contain a fuse within them. 

There is a useful calculator here for you.

1.4) Aging plug socket with high internal resistance

When plug sockets age, so do their internal parts. A plug socket contains several internal moving parts such as the shutters that open the Line and Neutral terminals when a plug top is inserted, the rocker switch that turns the power on and off to the terminals of the plug top and the internal metal parts. 

When any of these parts begins to wear, the tolerances tend to increase inside and create poorer electrical contact as metals no longer press tightly together. When a plug top is inserted into the socket the pins NEED to make good contact with the live parts inside and any wear or tear will prevent this from happening increasing electrical resistance and increasing heat as electrical current struggles to flow freely. 

1.5) Dirt or debris accumulate inside the plug socket

When dirt, dust or other debris accumulates inside the plug socket then there is a risk that internal metal components intended to touch each other will not make good contact. When this happens, a higher resistance develops than the manufacturer of the plug socket intended. Where high resistances occur electrical current struggles to flow and this results in a build up of heat. 

Where HEAT increases, electrical resistance FURTHER increases thus resulting in a vicious self-destructive cycle and very quickly the plug socket and plug top can melt through overheating. 

1.6) Incorrect fuse inserted

Whilst they are not common, 10-amp fuses are available on the market and if this kind of fuse is used in a tumble dryer that is rated at or above this current rating then excessive heat could be generated as current flows through. The correct rating of fuse should always be used, consult the manufacturer of the appliance if you are not sure. 

1.7) High ambient temperatures

Ambient temperatures above the normal room temperature can occur at the rear of a tumble dryer appliance. The rear of an appliance can become rather hot during normal operation of the dryer and should the plug socket be situated in this area, melting can occur! 

1.8) Extended and prolonged appliance use

Whilst appliances are safe to use as intended, prolonged and sustained use of a high powered appliance can cause overheating in a plug top causing melting of the sockets and plug. 13 amp fuses are not designed to continuously handle 13 amps sustained load and will become warm and even hot during sustained use. Hot fuses are a common occurrence when immersion heater tanks are protected in this manner and used on a prolonged basis. 
 

2) Is there anything I can do to prevent tumble drier plug failure?

As we have outlined the causes for tumble drier plug failure, the solutions for the prevention of this are as follows:

• If the plug socket that powers the equipment is old, have it replaced
• If the tumble dryer plug ever feels warm, replace the plug top with a new one using our handy guide mentioned above
• Do not use two high powered electrical appliances in the same plug socket as it will inevitably cause problems as some point for example a fire hazard. 

If the tumble dryer plug socket is old then it is likely that there are other plug sockets in your home that are also old and should be checked to ensure their safety. An electrical inspection is one of the best way to prevent future problems and alert you to any electrical issues that require your attention. 

There are also a number of steps that you can take yourself to check that your electrical installation in general is in good condition and to let you know when further action or electrician intervention is needed. 

3) Are some models more susceptible to failure?

Moulded plug tops that manufacturers use with appliances are made to BS1363 and are all of the same minimum standard. Appliances that may have been manufactured elsewhere in the world may NOT conform to the same standard and care should be taken to check that your appliance plug top meets the require standard. 

This is usually achieved by purchasing your appliance from a reputable source online or in a physical store. 

Generally speaking, all appliance plug tops should be absolutely fine. It is normally AGE and wear and tear creating poor contact that causes issues with plug tops on appliances and plug sockets. 

4) How much does a repair typically cost?

To replace a plug top, cable or plug socket in your home should generally fall under the minimum charge of any electrician. The minimum charge for a small job can range from £70 - £120 depending upon the area in which you are based and the company that you decide to use. Companies with larger overheads to cover will likely charge more than a smaller company. Whoever you choose to use for your small repairs, it is important that you check their reviews online, speak to friends and family to see if they have recommendations and speak with your contractor to gauge their knowledge and experience. 

5) Can I still use a damaged plug?

You should not use a damaged plug or plug socket it’s not a good idea. Once a plug top or plug socket becomes damaged it has deviated from the manufacturers specification and intended safety features. A damaged plug socket or plug top is likely to introduce danger of electric shock, electrocution, or fire and as such, should not be used until it has been repaired or replaced. 

6) Can I rewire the plug myself?

There are a number of home electrical tasks that may be performed at your own risk and amongst these are the wiring of a new plug on to an appliance. Great care should be taken to use the right tools and procedures to ensure that the task is carried out safely. We always recommend that electrical work is carried out by a qualified electrician in the first place to prevent a faulty socket or faulty plug from creating problems. 

There is an article about this on our site. 

7) What does a tumble dryer plug melted look like?

We can see from the photograph that there is visible damage to the plug socket. This is not a result of too much current in this case but rather a bad connection that is the possible cause of the overheating, melting and brown mark that has occurred. 

This plug socket and appliance was located in a utility room in the property and it was a good thing that the homeowners noticed the smell. There was also no smoke alarm in this room of the property so the discovery was reliant on the homeowners’ sense of smell. 

The original plug will need to be cut off this appliance, the wall socket will be replaced and a new plug socket and plug top will be attached to the appliance and wall.