External socket.

[cdbe]

This is my new gf ring (white), the grey goes under the patio to the external socket. Ring main is RCD protected. Can I just have the external as a simple spur? I'd rather not bother with a separate FCU (the "designer" sockets are quite difficult to match).

Thanks

 

[EFLImpudence]

Can I just have the external as a simple spur?

It'll be a simple spur whatever you do.

I'd rather not bother with a separate FCU (the "designer" sockets are quite difficult to match).

You don't need a fuse for one double socket on a spur - but a switch is a good idea.

 

[FrodoOne]

Can I just have the external as a simple spur? I'd rather not bother with a separate FCU (the "designer" sockets are quite difficult to match).

It'll be a simple spur whatever you do.

You don't need a fuse for one double socket on a spur - but a switch is a good idea.

Really !

Please enlighten me - as one who has no experience with 240 V "Rings"
(in a country where they are not allowed, by "Regulation").

If cdbe takes a "Spur" (via a 2.5 mm² cable - rated at 20 A)
from a "Ring" (via a 2.5 mm² cable, but "Ring" rated at 32 A)
to a "double socket",
on which two 13 A loads could be placed, (26 A in total),
would not a (20 A - or 13 A) Fused Connection Unit (FCU) then be required ?

Where would any "good idea" switch be placed,
what would it switch
and
why?

 

[EFLImpudence]

2.5mm² T&E has a ccc of 27A.

 

[ebee]

yes, usually ,unless derating factors dominate, a ring final of 2.5/1.5 T & E is sufficient for a 30 or 32A overcurrent protective device and is perfectly adequate to run a spur, unfused for one twin socket.

Ditto to a double pole switch being preference to isolate the outside socket if required for accidental damage/water ingress or just to stop sykes pinching your electric whilst you away on holiday.

So ELFI had a very good suggestion there.
Placing it somewhere convenient to get too and convenient for you to install along along the cable run too.
Maybe next to the inside socket you breaking off from the ring?

 

[EFLImpudence]

Really !

Yes, as Ebee has described.

As you have been on the forum for over seven years, I am surprised you have not encountered unfused spurs before; it is discussed frequently.

 

[Taylortwocities]

Yes, as Ebee has described.

As you have been on the forum for over seven years, I am surprised you have not encountered unfused spurs before; it is discussed frequently.

You have to remember that he “ain’t from round here “!

 

[ebee]

Well it`s not that far from here is it? not like its tother side of world is it? only 80% of half way round , I know I been there (well Brisbane and Sydney etc) only about 22.50 hours in the air if you fly there. When that bloke from Whitby set off it mighta been a bit further though. Left Tennant James Cook and his pals got to the Town of 1770 in about the year 1770, strange name for a town though innit, I been there too but don`t know why they called it that.

 

[FrodoOne]

Sydney Cove (the place of first landing) was named after the then Home Secretary, Thomas Townshend, 1st Viscount Sydney.

In 1770, Lieutenant James Cook named what, from the ocean appeared to be an inlet, after Sir George Jackson - one of the Lords Commissioners of the British Admiralty, and Judge Advocate of the Fleet.

In 1788, when the "First Fleet" reached its "destination" of Botany Bay, it was found to be unsuitable for early settlement.
(Little, if any, easily available fresh water and sandy soil.)

Governor Arthur Phillip took a longboat up the coast to sound the entrance and examine Cook's "Port Jackson".
He later wrote:-
"We got into Port Jackson early in the Afternoon, and had the satisfaction of finding
the finest Harbour in the World, in which a thousand Sail of the line may ride in the most perfect security...
I fixed on the one [cove] that had the best spring of Water, and in which the Ships can Anchor so close to the Shore."

"Sydney Harbour" is only part of "Port Jackson".

 

[plugwash]

If cdbe takes a "Spur" (via a 2.5 mm² cable - rated at 20 A)

The rating of 2.5mm T&E depends on installation conditions.

from a "Ring" (via a 2.5 mm² cable, but "Ring" rated at 32 A)
to a "double socket",
on which two 13 A loads could be placed, (26 A in total),

IIRC The normative part of BS7671 does not go into details on the exact structure of a ring circuit, it just say it can be "with or without spurs", that the cable must be at least 2.5mm² (or 1.5mm² if MICC) and that the cable must be rated at at least 20A and that the circuit must be designed such that sustained overloading is unlikely.

The guidiance in an appendix to the regulations, suggests that a spur should supply a maximum of one single or double socket, or one fused connection unit.

It seems clear to me that the opinion of those writing the standards was that it was unlikely that a double socket would supply more than one large load. This is reflected in BS1363, which only requires double sockets to be tested at a total of 20A.

could

Ultimately I think every countries electrical practices have things that would be rejected if looked at from first principles by modern health and safety types, but that have not caused enough problems in practice to justify banning them.

Where would any "good idea" switch be placed, what would it switch and why?

There are two main reasons a double pole switch feeding an outside socket is seen as a good idea by some installers.

The first is that water getting in to outside electrics is far from unheard of. Either due to poor quality products, poor installation, or misuse. When this happens it usually manifests itself as a RCD trip.

The second is the possibility of electricity theft.

In either of these scenarios being able to quickly and easilly disconnect the outside wiring without haveing to start taking stuff apart is useful.

 

[FrodoOne]

2.5mm² T&E has a ccc of 27A.

By which you may mean "Current Carrying Capacity".
(One should always define one's "abbreviations", for the benefit of the ignorant "reader".)

Yes, as Ebee has described.

As you have been on the forum for over seven years, I am surprised you have not encountered unfused spurs before; it is discussed frequently.

You have to remember that he “ain’t from round here “!

Thank you all for your "responses".

It is "interesting" that the "Current Carrying Capacity" of conductors is determined to be different under various "administrations".

It seems that, under some circumstances,
"2.5mm² T&E has a CCC of 27A." - in the UK.

However,
the following table shows that,
under AS/NZS 3000,
2.5mm² T&E is rated at only 20A "In thermal insulation partially surrounded"
but
is rated at 32 A "In Ground" !
(I doubt if one could describe an 'In Wall" situation as being "In Air".)

(Of course, it is from that that I based my previous comments - being "ignorant" of UK "specifications". [Mea Culpa])

It is also "interesting" that the US "National Electric Code" (NEC ) does not rate conductors up to 20 A until #12 AWG,
which has a CSA (Cross Sectional Area) of 3.31 mm².
(See https://en.wikipedia.org/wiki/American_wire_gauge )

The NEC seems to be much more "conservative" than the EU, UK or Australia/NZ.

 

[ebee]

(One should always define one's "abbreviations", for the benefit of the ignorant "reader".)

Bang on that man, I hate the proliferations of abbreviations and misnomers too