There are three types of fused connection units: - unswitched, switched with flex outlet and
switched without flex outlet. Fused connection units are used as a means of connecting
permanent appliances such as cooker hoods to the electrical circuits of the house.
Examples of uses of FCU are, cooker hoods (see Installing a cooker hood),
hidden sockets for kitchen appliances (see Installing wiring for kitchen appliances),
extractor fans (see Installing wiring for an extractor fan),
shaver sockets (see Installing a Shaver Socket) and waste
disposal units (see Installing wiring for a waste disposal unit).
SWITCH OFF ELECTRICITY AT THE MAINS BEFORE WORKING ON EXISTING CIRCUITS
To install a fused connection unit, break into the existing ring main or
more likely run a spur from an existing socket (see Adding a spur to a ring circuit from a socket),
or from a junction box (see Adding a spur to a ring circuit from a junction box).
Once this has been completed and the cable is running to the position where the new FCU is required, fit a
mounting box to hold the FCU securely in place, (see Installing a electrical mounting box
for full details of how to complete this task).
If the FCU used doen't have a built in flex outlet then run a cable to
a new socket which it will supply or a separate flex outlet. See the pages mentioned above for examples.
When the cables are in place and the mounting box fitted, fit the FCU.
On the FCU there should be 6 screw terminals, 3 for the mains supply and 3 for the load. The
flex for the appliance should be connected to the load terminals.
Strip and prepare the ends of the flex (see Preparing the cable for connection).
Connect the appliance flex to the 3 terminals. The FCU has three Load screw terminals
marked L (Live), N (Neutral) and E or 
(Earth).
The brown conductor should be fixed in the Live terminal (L), the blue fixed in the
Neutral (N) terminal and the green/yellow conductor into the Earth terminal (E or
) and tightened securely.
Now the FCU is ready to be connected to the Mains supply. Strip and prepare the ends of
the mains cable (see Preparing the cable for connection)
and place a length of green/yellow sleeving over the bare earth wire.
Next connect the mains cable to the FCU. The FCU has three Mains screw terminals
marked L (Live), N (Neutral) and E or (Earth).
The red conductor should be fixed in the Live terminal (L), the black fixed in the
Neutral (N) terminal and the bare wire with the green/yellow sleeving fitted
into the Earth terminal (E or ) and tightened
securely.
Finally screw the FCU in place.
