Cable length

[steve.t.]

How far can i take swa cable off a spured socket via a fcu, and what do i need to take into account.
any help would be great.

 

[mickys86]

You need to refer to OSG to take in to account volt drop. What sized cable is it? Bear in mind that the maximum fuse you can get in a FCU is 13amps

You also need to earth the outer sheath via a gland pack. Is the FCU metal clad??

 

[mickys86]

What are you wanting To do and how far away is it?

 

[ezzzekiel]

assuming your coming from the ring then you will need to know the max R1+R2 for the ring minus the actual R1+R2 of the ring wich will leave you with the maximum R1+R2 for the spur which would need putting into resistance formula and transposing to find the max length permissable for the spur.

if that makes sense, its clear as mud in my head

 

[mickys86]

assuming your coming from the ring then you will need to know the max R1+R2 for the ring minus the actual R1+R2 of the ring wich will leave you with the maximum R1+R2 for the spur which would need putting into resistance formula and transposing to find the max length permissable for the spur.

if that makes sense, its clear as mud in my head

What about volt drop ??

 

[High Tower]

How far can i take swa cable off a spured socket via a fcu, and what do i need to take into account.
any help would be great.

Just a few things mate,

Load ?
Supply?
Cable size?
Location?
Proposed length?

 

[steve.t.]

just a socket to run a water feature about 10m away.

 

[mickys86]

I'm not even gonna look in regs to see if that's ok and say it'll be fine lol

 

[Deleted member 26818]

You basically need to ensure that the Zs will be low enough for the fuse in the FCU to operate, and that the volt drop is no more than 5%.
Roughly measure the shortest leg of the RFC from the CU to where you intend positioning the FCU, then add the that to the 20m SWA, and as long as it's nowhere near the 106 m allowed for 2.5mm², you should be OK.
If it looks like it is going to be close, then you will have to check the Zs at the point closest to where you intend positioning the FCU, then add the calculated R1 + R2 for the 20m of 2,5mm² SWA and check the result is below 80% of the maximum tabulated value for the FCU fuse.

 

[mickys86]

I'm not even gonna look in regs to see if that's ok and say it'll be fine lol

Earth the sheath, water proof socket and use an adaptable box to connect the armoured to.

 

[High Tower]

Rcd !!!!!

 

[mickys86]

Rcd !!!!!

Arghhhh can't believe I forgot to mention that! Presumption is the biggest **** up! Lol

 

[steve.t.]

great. thanks.
the sockets are already rcd protected

 

[telectrix]

and, if you're coming off a spurred socket, your FCU needs to be moved upstream of that socket.