Adding Electrical Sockets To An Old Wiring System

When NEW SOCKETS WITH OLD WIRING are added, it can highlight a range of electrical issues with the home’s wiring system that are dangerous or potentially dangerous. Modern consumer unit technology will detect many of these electrical issues (but not all) whereas an old fuse box will fail to detect many problems.

1) Things that need to be considered

There are a number of considerations and checks that an electrician must make when installing additional electrical outlets into your home, these include:

• Compliance of the old system with new regulations
• Earthing suitability and safety connections
• Checks for circuit safety and condition
• Consumer unit supply capability
• Electric shock protection

2) Compliance of the old system with new regulations

The requirements for electrical installations (BS7671) are also known as the wiring regulations. This hefty (560 page+) document outlines the requirements for installing and maintaining electrical systems correctly and safely and should be followed in order to achieve a safe installation.

There are several regulations that cannot be met with very old systems and as such, some older wiring systems may need to be upgraded or replaced in order to be safely extended and modified in anyway.

Don’t misunderstand me, the electrical system will continue to function in many cases even with additions to old wiring BUT, the installation may well be in a dangerous state before or after modifications. There is a misconception with DIY enthusiasts that “if it works” then it’s fine or “electrics are easy” and I’m afraid that these two errors can lead to a variety of potentially serious
issues occurring.

Any electrical faults found prior to work being carried out will need to be rectified prior to installation.

3) Earthing suitability and safety connections

Electrical systems require safety paths to earth for any electrical faults that may occur. What does this mean? Well, in the event that appliances go faulty and become live, they need an earth path for the electrical system to effectively turn off the power. Without a sufficient earth path of low resistance, the appliance case could remain live and give someone a fatal electric shock.

The same applies to lighting circuits (and all circuits) in electrical systems. Unless there is a low resistance earth path, not enough electrical fault current will be generated to trip a circuit breaker or blow a fuse and disconnect the supply.

The earthing at the main supply needs to be checked to ensure that there is a good low resistance path available. The same also applies for checks to the electrical circuit earthing as well.

4) Checks for circuit safety and condition

Before an electrical circuit can be extended, altered, or a new electrical socket added, the wiring must be inspected and tested by a qualified electrician with the correct test equipment. This is to ensure that the circuit and installation can withstand any alterations and continue to perform safely and correctly.

The earth continuity will be checked to make sure there is a connection at every electrical accessory, the quality of cable insulation will be checked to ensure that there will be no problems with additions and the polarity of the circuit accessories will be checked.

Checks will also be carried out to ensure that the circuit cannot be overloaded, the protective device at the consumer unit will be checked and the size of the existing cables.

5) Consumer unit supply capability

Many older consumer units cannot supply additional circuits or further electrical outlets. Where a consumer unit or fuse box is particularly old, it may need to be replaced.

There may also not be enough spare ways (free slots for more circuit breakers) in the consumer unit meaning that an additional small consumer unit may need to be added or the main unit replaced.

The rating of the consumer unit will need to be checked to ensure that any additions are unlikely to exceed the maximum supply capability of the incoming power cable, the MAIN SWITCH or the Main Supply Fuse.

6) Electric shock protection

A vital part of any electrical system is its ability to prevent minor or fatal electric shocks. The earthing and bonding of conductive parts such as metal accessories and pipework goes some way to preventing this.

In more recent years electric shock protection has been improved by the addition of the RCD. The RCD (Residual Current Device or Ground Fault Circuit Interrupter) is a life-saving device that detects stray electrical currents leaking away from the cables and switches off the supply before the current reaches the level where someone could be seriously hurt.

Any electrical work that requires NEW SOCKETS WITH OLD WIRING would also include checking the age of any RCD devices and replacing where necessary. The RCD is also tested by the electrician to ensure that it is tripping under the correct current and within the required times.

This test is carried out using a calibrated RCD tester or Multifunction tester and the details recorded on any electrical certificate issued.

7) Pre-Checks on Older Systems

Where a new socket or several new plug sockets are to be added in older homes, it is often a good idea to have your home’s electrical system checked prior to installation. The best way of doing this is to ask your qualified electrician to carry out a periodic electrical inspection.

The electrical safety check will probe into all circuits and wiring within the home and produce a lengthy electrical report which will detail any issues that have been found. This electrical inspection is the best way of comparing the older system with the current electrical regulations and highlighting anything that requires improvement or repair along with detailing any dangers.

It is common to find issues on inspections such as loose connections (electrical fire risk), loose wires, damaged electrical cords, cracked outlet covers, overloaded socket outlets and more.

8) When should old outlets be replaced?

If your outlets are more than 20 years old then it is likely they will soon need replacing. Some outlets do not last this long and some will continue operating safely for longer. It depends on how much use and how much power has been demanded from the outlet along with the original quality of manufacturing.

Old outlets are common in an old home as many have never been changed. Loose connections are common problems in old outlets which can lead to a burnt outlet and are a general fire hazard.

9) Can I have new outlets with USB port?

Where new outlets are required with a USB port to charge mobile devices and other equipment, there are a few considerations and requirements that need to be adhered to. Many USB outlets will require a deeper back box than is currently installed. USB ports require some depth to actually receive the UBS lead itself along with the internal workings of the socket face therefore the socket faceplate of a USB device will require more depth in order to be safely mounted.

It needs this slightly greater depth to prevent crushing wires and creating short circuits along with wiring damage. A new box may need to be buried into the wall or a new surface mounting box installed to ensure that there is sufficient space for correct socket operation.

10) What is the cost of upgrading an old electrical system?

There are a few different costs that may need to be considered when upgrading old wiring to accept new electrical sockets safely and these costs are:

• New Earthing Connection to Mains
• Installing Main Equipotential Bonding
• Upgrading or installing a new RCD or GFCI device
• Replacing a Consumer Unit or Breaker Box
• Rewiring
• Repairs

The costs can vary unfortunately and it really does depend on the level of work that is required in order to put right any issue or update any parts of the system. New electrical work can be costly if there are lots of problems to put right.

Where older outlets are present, they should, as a minimum, be checked out be an electrician. Older homes often have new decorations and aesthetic improvements prioritised over an aging electrical system which can cause problems during renovation and afterwards if not addressed.

Remember if you have a really old socket, its likely the wiring is AT LEAST as old!

11) Can existing sockets be replaced or swapped?

There are less requirements to update the system if and existing socket is going to be swapped for a replacement. This is because there is generally no new load being added and no more danger than before should be present.

Your electrician will still carry out some checks though along with:

• Using New terminal screws to prevent damaging lugs,
• Examining the condition of the wiring,
• Visually inspecting for damage during replacement,
• Checking earthing and circuit continuity before and after completion

12) Summary

When considering NEW SOCKETS WITH OLD WIRING it is important to consider the possible age of the electrical wiring behind the socket. Copper wire is generally good for several decades before a full rewire is necessary and old wiring can last for many more decades if it is currently in good condition.

Circuits where there has been a lot of electrical current demand such as the kitchen, will likely need replacing before the lights for example.

Older houses can harbour electrical faults and hidden dangers so where wiring is old its important to have an electrical check carried out prior to any new installation work.