ring loop at end of radial?

[flashman25]

Will it make any difference if i connect the 1st and last sockets of a radial to make a loop?
If anyone can help, I've already searched thru the forums to no avail.

I plan to wire an outbuilding to use as an office.
The CU is 20m plus away. Total appliance ratings 6k.
Hoping to save money on cable by not installing circuit.
A radial I think will be ok, using 4mm twin+earth. am i correct?
will looping the 1st and last of the radial make any difference?

ps. the loop will be small (4m), at the end of 25m feed which in itself will have no sockets etc coming from it.

many thanks for your patience with my foolish questioning.

[Adam_151]

You sound quite wide of the mark there, but I'm not really sure what you are trying to describe, can you draw us a diagram?

Also are you familiar with aprt P of the building regulations?

[flashman25]

thanks for your help, I can't work out how to get an image up.

plainly having trouble putting it into words.

1 cable only coming from fuse box. with a ring stuck onto the end of it (using a junction box).
i'm not sure if this will help but.. imagine a lollipop. with a long stick, and a small head. the stick is the long cable from the fusebox and has no sockets or outlets except at the other end to the fuse where a ring is attached (the lolly head) which will have all the sockets on it.

i thought that
perhaps the load/supply maight be more evenly spread this way.

or perhaps i should just use a straight radial.

thanks again

[Steve]

I think he has a ring main in the house. He wants to run a single cable from this ring, to the shed, and put another ring in there.

There is no benefit to doing this.

You cannot use twin and earth outdoors or buried.

For 6kw of appliances I would run a 40A radial to the shed, from the consumer unit, run in 10mm² armoured cable.

This work is notifiable to your local council's building control under part P of the building regs. To not notify is an offence. An electrician would take care of this for you.

Saving money on electrical work is NOT an option. Either do it properly or not at all. Electricity kills. It has no prejudices. Could be your kids.

[flashman25]

I'm not quite so daft as to run that sort of thing from an existing ring. will be off its own mcb.
the outbuilding is attached to the house but currently (no pun) has no supply.
supply will not be exposed to the elements but go thru the adjoining wall inside appropriate conduit.
i know a ring circuit would be the ideal installation.
i was thinking i might have to install a radial then perhaps at a later date (when money is flowing faster) upgrade it to a ring.

really just curious , thanks





[fusebox]--------------------------------------------------o----o----o----o-I
. .I------------------------------------------------------------------------------l

is a ring


[fusebox]--------------------------------------------------o----o----o----o

is a radial




[fusebox]--------------------------------------------------o----o----o----o-I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .l------------------l

is my lollipop idea
a ring at the end of a
radial/spur direct to fusebox

where the cable is shown with --- I l
o is plug sockets
. . . . is because unable to put 'space' and should be ignored


all for idle curiosity.

thanks for your warnings, please be assured this will all be carried out in the safest way possible

[JohnD]

I think you are talking about a sub-main installation. You need a small CU at the outbuilding. Have a look in your wiring book.

[flashman25]

thanks john, makes a lot of sense.

to re: i can have long cable from dedicated mcb in main fusebox in house going to CU in the outbuilding and run a ring circuit from that.

seems tidy, thanks again

[sm1thson]

flashman25 wrote:

using a junction box

you want to use a mini cu (with RCD of course) to seperate the armoured run from the CU to the out building circuits, not a junction box.

[flashman25]

excellent advice guys, all is now clear. thank you all.