1) The cable going into the FCU is larger than that coming out (ignoring the fact that it's 2.5 going in, as in my setup)
The fuse is there to protect the cable.
13A fuse will protect a 1.5mm Cable, so diagram is correct.
You have used 2.5mm after the fuse so you are extra safe (not less safe).
2) That comment about the number of sockets being dependent on the load characteristics - I mean, it shouldn't make any difference, should it?
It makes a difference in that the Wiring Regulations and the user do not want a fuse blowing all the time because of bad circuit design.
In your case, 2 or 4 or 8 or 16 or 32 or 64 sockets in your garage will not blow the fuse because you do not have enough items to plug in and switch on at the same time to blow the fuse. YOU are likely to only use a few sockets at a time.
And so you have perfectly accounted for your diversity requirements in your situation.
In say a computer server room, you might consider how many sockets are connected off the FCU/ fuse, because in this scenario ALL the available sockets are likely to all be used. And having too many available sockets, of which all are in use, may cause the fuse to blow (Noting again that fuse will blow before damage to cable). So in this situation you might account for the diversity requirements by having (say) 4 sockets connected to the FCU.
SFK
The fuse is there to protect the cable.
13A fuse will protect a 1.5mm Cable, so diagram is correct.
You have used 2.5mm after the fuse so you are extra safe (not less safe).
2) That comment about the number of sockets being dependent on the load characteristics - I mean, it shouldn't make any difference, should it?
It makes a difference in that the Wiring Regulations and the user do not want a fuse blowing all the time because of bad circuit design.
In your case, 2 or 4 or 8 or 16 or 32 or 64 sockets in your garage will not blow the fuse because you do not have enough items to plug in and switch on at the same time to blow the fuse. YOU are likely to only use a few sockets at a time.
And so you have perfectly accounted for your diversity requirements in your situation.
In say a computer server room, you might consider how many sockets are connected off the FCU/ fuse, because in this scenario ALL the available sockets are likely to all be used. And having too many available sockets, of which all are in use, may cause the fuse to blow (Noting again that fuse will blow before damage to cable). So in this situation you might account for the diversity requirements by having (say) 4 sockets connected to the FCU.
SFK
Last edited: