Knightsbridge SN8420 20A Junction Box 4-Terminals White

Product Information

A junction box is a type of electrical enclosure that allows you to safely and easily join 2 or more pieces of cable together and ensure that any connections and terminals are well hidden and protected from causing injury or fire.

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! 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. 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 Bus Bar screw terminals - with these types of terminals, each cable core has its own location hole and screw for securing to a terminal. The number of cores which can be joined is limited by the number of holes/screws in each terminal - these can vary from 2 to 6.Electrical junction boxes come in a range of different types. There are two key differences that you will need to look out for when purchasing your junction box: You can also read a brief synopsis on the electrical guidelines and what they mean by visiting our Approved Document P project here. 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. There are also different styles of junction boxes that you can use. Each will differ slightly depending manufacturer (terminal layout, slightly different mouldings etc….), but the essentials should all be the same:

Junction boxes are rated in amps (typically 5, 20 or 30 amp). The size used should equate to the current rating of the circuit being connected into - you can always use a higher rated box than the circuit but never a lower rated box. If you have ever needed to join 2 sections of cable or wire together or create an additional spur for a new piece of cable then you should be well aware of the existence of the junction box and if not, this is the product you want if you are needing to do either of these jobs.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 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 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! Step 4 – Fix and Close Junction Box: Once you have ensured that each terminal screw is screwed down nice and tight, screw the junction box to a nearby joist or timber and then screw the cap down on

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 Junction Box with spur wiring diagram – Adding a Spur using a Junction box Fixing cables into the Junction BoxStep 1 – Isolate Power: Before doing anything at all, the very first job is to isolate the power to the circuit you are going to be working on! Each of the earth cores of the cables should be covered with green/yellow earth sleeving within the box. For a lighting circuit use a 20amp junction box and for a ring main or radial circuit use a 30 amp junction box. Terminals The main reason for this change was to ensure that any cabling used from that point onwards would harmonise (be the same) as those used in Europe. Stripping the inner cores of the cable should be such that minimal conductor is exposed once the connection has been made.