Junction box after fused spur
- Thread starter Doitalone
- Start date
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Yes, assuming the left-hand socket is not already on a spur -
but can you not make the joints in one of the sockets?
but can you not make the joints in one of the sockets?
OR - You could just use 4mm² T&E for the spur cable and then no fuse is required for multiple sockets on the spur.
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Yes, assuming the left-hand socket is not already on a spur -
but it won't be another circuit; it will become part of that circuit.
but it won't be another circuit; it will become part of that circuit.
It doesn't matter as long as all the sockets are protected by one 13A fuse in one Fused Connector Unit - even if you have another FCU somewhere.
Your circuit (ring or radial) is the "main circuit" in this instance and you fuse down with an FCU with a fuse onboard.
By definition your circuit starts at a fuse (or Breaker) then any other fuses makes a new circuit (or sub circuit).
So your FCU starts a new circuit (sub circuit) .
Any number of items can be wired from the fused side of the FCU and in pretty much any fashion - to A, then A to B, then B to C etc etc, is one way.
Another way is to branch off, often known as trees.
So option 1/ or 2/ or 3/ are all correct because the all go via the 13A max fuse - you might not actually need the second FCU in option 2/ unless you specifically want to fuse down from the first FCU.
Note - it is the wiring from this main circuit (ring or radial) that is the "spur" whether you use an FCU to fuse down or not - just some people call the FCU itself a "spur" but it is the wrong term.
It probably comes about because a FCU is often used to make a spur become a fused spur rather than a simple unfused spur.
There are a few other terms that are often used wrongly and this can sometimes cause confusion.
We probably all use incorrect terms in many aspects of life besides electrics.
By definition your circuit starts at a fuse (or Breaker) then any other fuses makes a new circuit (or sub circuit).
So your FCU starts a new circuit (sub circuit) .
Any number of items can be wired from the fused side of the FCU and in pretty much any fashion - to A, then A to B, then B to C etc etc, is one way.
Another way is to branch off, often known as trees.
So option 1/ or 2/ or 3/ are all correct because the all go via the 13A max fuse - you might not actually need the second FCU in option 2/ unless you specifically want to fuse down from the first FCU.
Note - it is the wiring from this main circuit (ring or radial) that is the "spur" whether you use an FCU to fuse down or not - just some people call the FCU itself a "spur" but it is the wrong term.
It probably comes about because a FCU is often used to make a spur become a fused spur rather than a simple unfused spur.
There are a few other terms that are often used wrongly and this can sometimes cause confusion.
We probably all use incorrect terms in many aspects of life besides electrics.
Just to also point out that the need to 'fuse down' comes about because the cable being used for the spur does not have sufficient current-carrying-capacity for the over-current device on the main circuit.
That is on a UK socket circuit usually 32A so (as I indicated above) were you to use a cable for the spur that has a CCC >32A, i.e. (4mm²), or were the OCD less than the 27A CCC of the 2.5mm² cable then no fuses would be necessary.
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