Knightsbridge SN8420 20A Junction Box 4-Terminals White

Product Information

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. Likewise, the cables running into and out of the junction box should also be secured to a suitable, stable surface. If not, then “mechanical strain” could take place and over time, wires may become loose causing loose connections. Each of the earth cores of the cables should be covered with green/yellow earth sleeving within the 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! In short they are used for joining wires or running a spur from an electrical circuit safely. Whenever you need to join two or more electrical wires, then you should use a junction box. As a result they are commonly used and very useful for anyone involved in wiring and electrics.

4 Terminal Junction Boxes

Junction boxes can also be used to add lights and switches. For more information please see our lights and switches project. 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 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! 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 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.

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. Stripping the inner cores of the cable should be such that minimal conductor is exposed once the connection has been made. 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 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. Step 1 – Isolate Power: Before you do anything at all, first isolate the power to the circuit you are working on!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 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 We will explain the differences between these types of junction box and their various benefits shortly, however it is important that you have the right rating whichever type that you choose. Junction Box Amp Rating Single screw point terminal - as the name implies, each terminal has just one large screw which is used to secure all the cable cores being joined together.

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.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 As we have stated in the how to wire section above, junction boxes must be fixed solidly to a firm, suitable surface and must be accessible! These rules are stipulated in the latest 18th edition regulations and must be adhered to. Screw the base of the junction box to a joist or rafter through the securing holes indicated in the image 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!