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45 Amblecote Road | London | SE12 9TN
Mon-Fri 08:00 AM - 05:00 PM
45 Amblecote Road | London | SE12 9TN
Mon-Fri 08:00 AM - 05:00 PM
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    22 Sep, 2021
    Posted by Ihor Ovchynnyk
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    Ring Main Circuit

    What is a Ring Main?

    Ring main circuit is a terminology used in London and around the UK to describe the final circuit of wiring. It gets its electrical power from the consumer unit and distributes it around the house. When it comes to configuring it, it is as easy as it sounds.

    You first need to connect the ring main cable from the consumer unit to the ring main, and then take it to the socket and return it to the ring main connecting it finally to the electrical mains. In other words, the ring main acts as the manager between all the wiring of the house and the consumer unit.

    It typically has 2.5mm of wires coming and going through it. Moreover, in a ring main, one should make sure that the earth wires, neutral connections, and live wires are connected appropriately while going in and out of the ring main. However, if you are manually wiring a socket, ensure to use a ring main diagram for reference, so that you could be well-equipped and well-educated about the electrical settings.

    A ring main is also used to lower the load on electrical wires. If a long wire connects from the consumer unit to the socket, it can increase the load on the wire, leading to disastrous results. Thus, the ring main helps to reduce the load on the wires by distributing it evenly.

    Ring Main Wiring

    Wiring a ring main has to be executed carefully. These wirings works are not carried out several times so, when the work of the ring main is taken up, it has to be crafted to perfection.

    Although it can have numerous sockets and fused connection units, it has a fixed load capacity. The maximum load is said to be around 7200 watts. Moreover, the ring main is protected by a 32 amp fuse spur or 32 amp circuit breaker.

    The main wire starts and ends at the consumer unit. In the journey, it travels to rooms, kitchens, bathrooms and connects to all the sockets and fused connections of the house. The ring main circuit ideally serves an area of 120 square yards.

    Ring Main Circuit

    Also, there can be more than one ring mains depending on the floors, size, and electricity load of the house. Generally, it is better to have one different ring main for the kitchen, as it has appliances that consume a maximum load of electricity.

    There is also a radial circuit that provides power to houses. But in the UK, ring main is used on a large scale, compared to the radial circuit.

    The basic difference between them is, that in a radial circuit the wires do not complete a loop to the consumer unit, thus making it eligible for converting it into a ring main and vice versa (by altering the wirings).

    Nonetheless, if you need to identify whether you have a radial circuit or the main ring in your home electrical system, certain tests need to be carried out. But, You should test the wirings only if you know electrical engineering.

    Spurs on The Ring Main

    As the main ring has its limitations for the length of cables and the load it can carry, there are spurs installed on the ring main for devices that utilize the maximum electricity load. These devices are mainly cooktops, washing machines, dishwashers, geysers, and more.

    This switched fuse spur allows the devices to be switched on or off from a convenient position.

    For example, a cooktop generally has a socket underneath the installation which is a very inaccessible area. Thus a fused spur can be installed on the top of the hob from wherein the hob can be easily operated.

    Spurs on The Ring Main

    A spur also serves the purpose of adding an extra socket to an existing ring main circuit, thus, eliminating the need to wire a socket back to the consumer unit. The wire is directly attached to the nearest ring main socket!

    Design and Protection for Ring Main Circuits

    The ring main circuit is an essential electrical component of the house. Thus, no compromise should be made in the wiring design. Moreover, the design for the ring main circuit must adhere to all safety guidelines as per the socket wiring diagram for the UK.

    Also, the ring main circuit starts the wiring process and ends it too. Thus there are two electric cables for all specifications. You can use a 2.5 mm 2 twin and earth cable protected by a 32A type B MCB to have a ring main circuit. This coverage is ideal for domestic use.

    Ring Main or Ring Final Circuit

    The ring main or the ring final circuit is the basic component of a domestic electrical system. There may be one ring main for the entire household, but it is advisable to have one for the ground floor and, one for the first floor.

    You may need to install a separate kitchen ring main, due to the electrical load of the appliances. Additionally, a ring main has its own set of restrictions, hence, it is essential to check with the length of the cable, the number of fused spurs, and radial circuits installed to be safe in all aspects.

    Cable Used for The Main Ring

    A ring main comprises of earth, neutral and live wires. These have to connect to the earth, main and live wires respectively. A ring main uses a 2.5mm cable (cross-sectional area of the wires) for the best supply. The live wire carries the current from the consumer unit to all the appliances of the houses.

    Cable Used for The Main Ring

    The earth and neutral wires assure smooth functioning and supply of electricity to and from the consumer unit. Nonetheless, the earthing and neutral wires need to be secured to avoid shocks and leakage of electricity.

    Floor Area for Ring Main

    The ring main floor area is different for domestic and industrial use. The ring main floor area for domestic use should not exceed 100m2. This ring main cable size should be 2.5 mm and, the length of the wire should not exceed 100m. For domestic purposes, you can follow according to the area specifications.

    Length of Cable Limitations in Ring and Radial circuits

    The cross-sectional length of the cable should be 2.5mm, limiting to an area of 100m2. However, there may be circumstances wherein the length needs to be more than 100m2 for the ring main. In such cases, it can be extended a little, but it is not recommended and should be handled with extreme caution.

    Talking about radial circuits, several sockets can be installed on the same. These circuits and sockets need to be connected with 2.5mm cables. The radial circuit should have a cable length of not more than 100 m2.

    How Does a Final Ring Circuit or Ring Main Work?

    The final ring circuit or the ring main works by connecting the wires from the consumer unit to all the appliances in the house and then back to the consumer unit. Further, the live wires carry electricity from the consumer unit to the ring main and then the appliances and back again.

    The socket ring main is generally protected by a 16A/20A or 32A fuse or circuit breaker. Thus the ring main acts as an essential electrical circuit in the house. In brief, the flow of electricity is transferred, maintained, and protected by the ring main.

    Testing for a Ring or Radial Circuit

    If you want to know whether a ring or radial circuit is installed at your place, you can do it with the help of various tests. Perform these tests only if you know the wiring of the ring main to the consumer unit. This testing is done with the help of a resistance tester or with a low reading ohm meter function. Whenever you plan to perform this test by yourself or ask someone for help, ensure that a safe isolation procedure is carried out and you know the basic house wiring rules.

    Testing for a Ring or Radial Circuit

    Below are the steps in detail:

    1. From the distribution board, remove the line, neutral, and earth cables from its terminals. If it is a ring circuit, it will have two of each cable in the same terminal.
    2. Then select the low reading ohm meter function and set the tester to ‘null’.
    3. ‘r1’ will be the reading for live to live, ‘r2’ will be for the earth to earth, and ‘rn’ will be for neutral to neutral.
    4. By using the tester, determine live and earth wires. Then connect live 1(outgoing) to the earth (incoming) and live 1 (incoming) to earth (outgoing).
    5. Note down these readings and, calculate the ohm value using the formula: (r1+r2)/4. The value should be not more or too less than 0.5 ohms. If the value deviates, it requires checking.
    6. Once you have completed checking with all the wires, connect them back to their respective terminals.

    There are other procedures also available to test the circuits. If you are not familiar with wiring work, it would be a better idea to hire an expert electrician to do it for you!


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