The wiring of a four-terminal junction box Two of the cables entering the junction box are the main circuit cables.
This is much simpler than it appears, for ease of explanation I have numbered the three terminals at the ceiling rose. I like the ashley J701 with 15 amp connector strip, loads of room and good terminal capacity, theres even a circuit designation card in the lid.
Information and plans should be independently checked and verified before action. Never take risks with electrical safety.
This is a typical example of a lighting circuit as seen from the loft. You will often see these used in old looped radial circuits instead of a ceiling rose in older houses.
But if you're running high-wattage floodlights or a big multi-bulb chandelier, you'll need even fewer outlets if you want to avoid overloading the circuit.
The current flows from the main circuit down the brown core to the switch, then if the switch is on and the circuit therefore unbroken back up the blue core and along the brown core to the light, before finally returning through the light cable blue core to the neutral terminal in the box. There is very little difference in price between the 5A and 20A types, so there is no point in using the 5A ones, unless the physical size of the box is an issue.
Lighting circuits in the home are normally protected by a 5 amp fuse or a 6 amp circuit breaker, there are normally 2 circuits one for upstairs and one for the ground floor.
For more information on electric showers, see Installing an electric shower. Before you start any type of electrical work, you must follow these following safety precautions:.
Two way switching means having two or more switches in different locations to control one lamp. 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. Bathroom lighting The steamy, damp environment of a bathroom greatly increases the potential dangers of any electrical fitting.
Complete rewires and a number of other electrical jobs are now covered by Part P of the building regulations. This cable is passed through the hole in the ceiling and wired directly to the light fitting, remember to put red tape around the black insulation as this is the switched live!
For your safety, electrical products must be installed in accordance with local Building Regulations. They can also be used to make repairs where a section of cable needs to be replaced. Split load CUs are recommended, and this article will assume the use of a split load CU. Installations with plain green sleeving on the earth wires will typically be approaching 40 years old and are likely to require replacement.
There are also limitations to the type of electrical equipment permitted in each zone. The loop in wiring system is straight forwards but has the disadvantage of making it difficult to replace the ceiling rose for a more modern style light fitting.
A cable is now joined to Neutral terminal 3 and switched live terminal 1 and earth. Most kitchens are supplied by one ring circuit.
Chester , Aug 5, 2004. Junction-box circuits The reason why the wiring of a lighting circuit is more complex than a power circuit is that each outlet or light fitting needs to be controlled by a separate switch. Most metal light fittings and switches will require earthing , but those marked with the double insulated symbol do not need an earth connection.