Appliances which are located in a permanent position may be connected to the power supply with a fused connection unit. Some in fact may only be connected in this way.
For bathrooms, these must be mounted out of reach – outside the room, or for an appliance like a radiant heater (which itself must be mounted high up), high enough that it cannot be touched when using the bath or basin.
These units have their own fuse which provides additional protection at this point. They can be connected as part of a ring main, as a spur from a ring main or on their own radial circuit. Indeed for some appliances the latter is the only allowable method, and you should employ a professional electrician to do this work.
The procedure for installing a fused connection unit in a ring main or as a spur from a ring main is similar to that for a socket outlet. The difference being that the flex or cable for the appliance also has to be connected. Full details for installing a socket outlet can be found in these articles:
- Socket outlets - extending the ring main
- Socket outlets - spur from a junction box
- Socket outlets - spur from existing socket
Connecting the fused connection unit
1. Switch off the power at the consumer unit for the circuit concerned. If you have removable fuses at your consumer unit, switch off the power at the consumer unit and remove the fuse for this circuit.
3. Mount the back box or pattress for the fused connection unit. The way to do this will depend on the type of fitting and the wall. You may use a Surface Mounted Box, a Flush Mounted Metal Box, or a Flush Mounted Plasterboard Box.
For this example we are mounting a flush box in plasterboard.
14. There will also be two earth terminals appropriately marked with the earth symbol.
15. Depending on whether this FCU is being connected as a spur or as part of the ring main you will have either one or two cables. For this example we are connecting it as a spur from an adjacent socket outlet and therefore have just one cable.
Connecting the appliance
19. Make sure that the flex or cable has already been correctly connected to the appliance itself.
20. Some types of FCU have the appliance outlet though the faceplate. If you have this type, feed the flex through the faceplate first.
21. Strip and prepare the flex in the normal way, separating the conductors and trimming back the insulation of each by about ½”. Twist the individual filaments of each conductor.
22. Slacken the screws on the terminals marked ‘N LOAD’ and ‘L LOAD’ as well as the corresponding earth terminal.
27. Finally, double check that all your connections are firmly secured and that the insulated part butts up to the terminals leaving no exposed conductor.
30. Once you are sure that all work has been completed correctly, switch the power back on at the consumer unit. In the case of removable fuses, replace the fuse for the circuit, and switch the power back on.