how long can a spur cable be

[oldandtired]

I want t run a spur(using 2.5mm cable) from a socket on a ring main . how long can the spur cable be?

 

[James]

There are no specific regs as to how long it is.
However it will have to meet regulations regarding volt drop calculations.

 

[telectrix]

as long as the Zs at the spurred socket is below 1.09 ohms it's good (assuming a 32A type B MCB), and of course VD below 5%. (11.5V).

 

[Dustydazzler]

If if longer than a drum of 2.5 then its too far...
In all seriousness if we are talking domesticated dwellings then it’s unlikely to ever exceed maximum permissible lengthy

 

[oldandtired]

There are no specific regs as to how long it is.
However it will have to meet regulations regarding volt drop calculations.

not sure how to do v/drop calc , the spur will be approx 4m. i want to run a tumble dryer from the spurred socket

 

[Pete999]

I want t run a spur(using 2.5mm cable) from a socket on a ring main . how long can the spur cable be?

Lots of imponderables to deal with Voltage at final destination ( have any volt drop calculations been done?)
[automerge]1570541797[/automerge]

not sure how to do v/drop calc , the spur will be approx 4m. i want to run a tumble dryer from the spurred socket

What is the Electrical load of the tumble dryer?

 

[telectrix]

if you're going to run 4m 2.5 cable, why not run 2 cables and extend ring in existing socket using wagos or ideal in line splice connectors. it's less than a fiver for extra materials

 

[oldandtired]

Lots of imponderables to deal with Voltage at final destination ( have any volt drop calculations been done?)
[automerge]1570541797[/automerge]

What is the Electrical load of the tumble dryer?
[/QU

if you're going to run 4m 2.5 cable, why not run 2 cables and extend ring in existing socket using wagos or ideal in line splice connectors. it's less than a fiver for extra materials

thought about extending ring but nearest point to break into it easily and fit conector block will be 6/7m . The 4m length would be fed from back of socket.

 

[telectrix]

why can't you run 2 legs from the socket. joint in back box?like here?

 

[Pete999]

thought about extending ring but nearest point to break into it easily and fit conector block will be 6/7m . The 4m length would be fed from back of socket.

You will need to be certain that the socket you intend spurring from is actually part of a RFC and not already a spur from the RFC, and your addition is NOT a spur from an existing Spur

 

[oldandtired]

You will need to be certain that the socket you intend spurring from is actually part of a RFC and not already a spur from the RFC, and your addition is NOT a spur from an existing Spur

the socket I am intending to spur from is part of the ring main. and is not a spur
[automerge]1570543634[/automerge]

if you're going to run 4m 2.5 cable, why not run 2 cables and extend ring in existing socket using wagos or ideal in line splice connectors. it's less than a fiver for extra materials

thanks , will have another look at options

 

[telectrix]

the socket I am intending to spur from is part of the ring main. and is not a spur
[automerge]1570543634[/automerge]

thanks , will have another look at options

see picture in post #9. it's 1 I did last year. obviouslytrhe red/blacks are existing. the brown/blues are my rfc extension., clipped about 3m under floor in crawl space. ( this is what thin apprentices are for. ).

 

[Deleted member 105166]

In all seriousness if we are talking domesticated dwellings then it’s unlikely to ever exceed maximum permissible lengthy

Don't say that, those none the wiser will take as licence to take a 2.5 T/E spur to their domesticated garden shed or barbeque position at the bottom of the garden!

 

[Dustydazzler]

Don't say that, those none the wiser will take as licence to take a 2.5 T/E spur to their domesticated garden shed or barbeque position at the bottom of the garden!

I should have said ‘within’ the domesticated dwelling

 

[sparks1234]

if you're going to run 4m 2.5 cable, why not run 2 cables and extend ring in existing socket using wagos or ideal in line splice connectors. it's less than a fiver for extra materials

Because there is no point