Knightsbridge SN8420 20A Junction Box 4-Terminals White

Product Information

Stripping the inner cores of the cable should be such that minimal conductor is exposed once the connection has been made. Single screw terminal – The terminal has one screw which is screwed closed on to the cable cores being joined together to secure them all in one single connection point. These are typically found in the Standard junction box, and allow the connection of a larger number or sizes of cable cores that the other terminal types

Each of the earth cores of the cables should be covered with green/yellow earth sleeving within the box. The cable cores will need to be stripped before being inserted into the terminals. Try to expose the minimum amount of the conductor as necessary. 10 – 12mm will be typically sufficient for this, unless you are doubling them over then around 15mm is required. Junction boxes are rated in amps to protect them, you and the circuit. Make sure you have the right box for the right job. A ring main ( more about ring mains can be found in our project here) and also a radial circuit ( more about radial circuits in our project here) will need a 30 amp junction box, whereas a lighting circuit (although you can buy 5amp junction boxes) will need a 20amp junction box.Step 3 – Connect to Terminals: Once all stripped, connect each core wire to an individual terminal ensuring that each type of core is connected to the same from the other cable, e.g. a 3 brown lives in one terminal, all 3 blue neutrals in another terminal and all 3 earths in another terminal. Also ensure that you add earth sheath to each bare earth wire – This has to be done by law! Junction boxes can also be used to add lights and switches. For more information please see our lights and switches project. This section explains how to wire a traditional or standard style junction box. It doesn’t matter about the rating or number of terminals, the process is the same in each case. Joining Two Sections of Wire Together One thing to watch out for with the number of terminals, is the type of terminal used. Two basic types are available: In this guide we take a look at junction boxes and how they are wired up and used, read on to find out more. Working With Electricity and Junction Boxes

When using junction boxes to extend ring mains or radial circuits, remember that the regulations limit the length of cable for both ring and radial circuits, and also how spurs are connected to ring mains. These regulations must be adhered to to avoid possible overloading the electrical wiring.The cover should always be fixed in place using the screw (or screws) provided - the position of the internal wiring may need to be adjusted to allow the cover to sit on the body of the junction box before securing - never use the cover screws to force the cover down onto the cables, this can cause damage. Examples of Junction Box use A problem when purchasing Junction Boxes is to know which type of terminal is fitted and, where Bus Bars are fitted, how many cable cores can be connected to each terminal. Using Junction Boxes When it comes to wiring up junction boxes, as you would expect, there are some quite strict rules on how they are wired, where they can be placed and how any cables should be secured. All of this is covered below.

Electricity is dangerous, that’s a fact! We are all taught this from a very young age. When it comes to the electrics in your home, unless you know what you are doing or are a “competant person” then you should leave it well alone!

Once the junction box has been fixed to a secure surface, and the wiring has been connected to the terminals and tested you can close the junction box, they must never be left open and exposed. The cover is screwed closed using the provided securing screw (or possibly screws) through the cover and fixing it to the base. It is often necessary to adjust the wiring inside the junction box to allow the cover to close. Avoid simply forcing the cover closed with the screw as this can risk causing damage to cables.

Step 3 – Connect Wires: Once all stripped, connect the same core wire from each length of cable to the same terminal in the junction box e.g. brown live to live, blue neutral to neutral and earths to earth (remember to add some earth sheath to the earth wires – this is a legal requirement!). Make sure you screw each terminal screw down nice and tight Increasingly common are the “Maintenance Free” Junction boxes. These are designed to replace the standard round junction boxes commonly use in household wiring. The reason that they have become so popular is that they can save nearly 75% of the time required to wire a traditional junction box.In terms of accessibility, this means that a builder or electrician can easily remove part of the floor or ceiling etc. and access the junction box when required. Junction boxes may not be buried in plaster or other similar materials.