Many electrical problems are minor. However, if you notice any of the following issues, you should get in contact with one of the electricians in your local area as soon as possible, as these things could be an indication of a major electrical issue.
Scorch marks on your plug sockets
Black or brownish scorch marks on the plug sockets in a room should not be ignored, particularly if the sockets in question also produce a loud buzzing sound when you plug a device into them, and their plastic covering becomes very hot whilst they are in use.
This is usually a sign that a property's electrical system has overheated. Overheating can be caused by overloading the system with more electrical appliances than it can handle.
Overloading is a common issue in old houses, as these properties were not designed to cope with the quantity and high voltage of electrical goods that are used in most homes today.
An overloaded, overheating system could potentially cause a fire if the electrical cables that make up the system reach such a high heat that they start to melt. As such, it is important to have an electrician address this problem as soon as you notice it. This type of issue can usually be rectified by either upgrading the existing fuse box or rewiring the entire property.
Sparking plug sockets
It's quite normal to see a tiny spark when you first plug an electrical device into a plug socket. However, if the sparks continue to appear after the device has been plugged in for several seconds, it could be a sign of a serious wiring problem.
This sparking can be caused by frayed electrical wires or wires which have become so corroded or grimy that they no longer allow electricity to safely pass through them. It can also occur when there is a water leak somewhere behind the wall, close to the electrical wires.
Much like the aforementioned scorch marks, sparking can lead to a fire, particularly if there are any flammable items (such as paper, cloth or solvents) located close to the plug socket. If the sparking is the result of a water leak, anyone who uses the socket could end up being electrocuted.
As such, this is really not an issue which should be ignored. Avoid using the affected socket until the problem has been fixed. For more information, contact an electrician.