2 Spurs off a socket (ring)

[Risteard]

However, do you feel that it is an equally "appalling practice" to take spurs from two different sockets that are just a few inches apart (and, again, without consideration of what part of the ring is concerned).

It is not necessarily wrong to spur off two outlets nearby, but certainly it is required that consideration be given to the effects it will have on the ring. If you believe that it will unduly influence the current balance on the ring then it obviously is not permissible to do that.

In the south of Ireland they have prevented all of this kind of nonsense by prohibiting unfused (or "non-fused" as they are described) spurs.

 

[Taylortwocities]

In the south of Ireland they have prevented all of this kind of nonsense by prohibiting unfused (or "non-fused" as they are described) spurs.

Regulations and rules in remote offshoots of Europe have nothing to do what both you and I need to do in the United Kingdom.

 

[ban-all-sheds]

do you feel that it is an equally "appalling practice" to take spurs from two different sockets that are just a few inches apart (and, again, without consideration of what part of the ring is concerned).

Methinks "appalling" is a trifle extreme.

But whether you do it by spurring from two different sockets that are just a few inches apart, or by taking two spurs from one socket, or indeed simply installing multiple sockets right next to each other, or something like this:

is irrelevant. All of those cases require you to think about the loading on the ring segments.

 

[ban-all-sheds]

In the south of Ireland they have prevented all of this kind of nonsense

But not in any part of Ulster? How come?

by prohibiting unfused (or "non-fused" as they are described) spurs.

So fused spurs are allowed?

(Assuming it does) how does installing, say, 4 FCUs within 340mm prevent the nonsense of having to worry about overloading a segment of the ring?

 

[JohnW2]

It is not necessarily wrong to spur off two outlets nearby ...

Indeed and, by the same token, it is not necessarily wrong (let alone 'appalling'!) to take two spurs from the same point on a ring (like one socket), provided only that the terminals can accommodate 4 conductors.

... but certainly it is required that consideration be given to the effects it will have on the ring. If you believe that it will unduly influence the current balance on the ring then it obviously is not permissible to do that.

Again, indeed, but I suspect that many of the people who are averse to two spurs from one point, or very close points, on a ring (or, indeed, to having two or more sockets close together on a ring) having given no, or inadequate, thought to the possible consequences - because, in many cases, proper consideration would tell them that there was no 'problem' ....

... if one considers the common situation of a 32A ring final wired in Method C 2.5mm² cable (hence CCC=27A), even in the most extreme situation (a total load of 32A applied to a single point on the ring), it is impossible for any cable to be overloaded unless the 'point' is closer than about 16% (of total ring length) from one end of the ring. If the designer has enough common sense to design on the basis of a less extreme situation than that (no-one is going to connect a 32A load to one point on a ring!), then one can have multiple spurs or sockets much closer to the end of the ring than that without any risk of any cable being overloaded.

... and, as above, this does not only apply to spurs. It also applies when there are several sockets in close proximity on a ring (as often seen in kitchens and workshops) - and, again, a little calculation, on the base of realistic common sense assumptions, will also usually indicate that such a practice is anything but "appalling".

Kind Regards, John

 

[ban-all-sheds]

OTOH, 4 single sockets within 340mm could easily overload a segment, no matter where they were.

 

[EFLImpudence]

(although an Informative appendix does reject the idea)

No it doesn't; it just doesn't illustrate it.

however yes certainly many (most/all) socket outlets are not designed to accomodate four or more conductors in each terminal.

What exactly does that mean?

If four conductors fit in comfortably, does that mean it was designed for four conductors or just made too big for what it was designed for?

4 x 2.5 < 3 x 4

Are some sockets designed so that you cannot branch from a 32A 4mm² radial?

 

[Risteard]

If four conductors fit in comfortably, does that mean it was designed for four conductors or just made too big for what it was designed for?

If you read the specifications from the manufacturers (or indeed BS1363) you will see that four conductors isn't acceptable.

 

[JohnW2]

OTOH, 4 single sockets within 340mm could easily overload a segment, no matter where they were.

I don't understand that (if far enough from an end of the ring), unless you are considering total loads greater than the (usually 32A) design current of the circuit.

Kind Regards, John

 

[EFLImpudence]

If you read the specifications from the manufacturers (or indeed BS1363) you will see that four conductors isn't acceptable.

I think you are taking things too literally, as you are with (informative) App 15.

This from MK -

Using your logic, you cannot use only two conductors except with 6mm².
Quite rightly you can say that is ridiculous.

As it has the 'capacity' for two 6mm² conductors, then, clearly, it will accept four 2.5mm².
Is your objection to 4 x 2.5 merely that MK have not specifically given you the go ahead or do you think damage will be done, either electrically or mechanically?

 

[stillp]

If you read the specifications from the manufacturers (or indeed BS1363) you will see that four conductors isn't acceptable.

There's nothing in BS1363 that prohibits terminals capable of accepting four (or more) conductors, only that they shall accept one, two or three 2.5mm² or one or two 4mm² conductors in the live terminals,, and one, two or three 1.5mm² or 2.5mm² or one or two 4mm² in the earthing terminals.

 

[JohnW2]

There's nothing in BS1363 that prohibits terminals capable of accepting four (or more) conductors, only that they shall accept one, two or three 2.5mm² or one or two 4mm² conductors in the live terminals ...

Interesting. When you say 'accept', is the requirement simply that the terminals should be able to physically accommodate the conductors, or are some functional 'tests' involved.

What you say about 4mm² conductors is interesting. EFLI was therefore probably right to question whether there are some (BS1363-compliant) sockets that could not accommodate a branch in a 4mm² radial - and from what you say, it sounds as if a socket could be BS1363-compliant but not able to allow such a branch - is that the case?

Kind Regards, John

 

[stillp]

Interesting. When you say 'accept', is the requirement simply that the terminals should be able to physically accommodate the conductors, or are some functional 'tests' involved.

"Compliance shall be checked by inspection and by fitting the appropriate conductors."

a socket could be BS1363-compliant but not able to allow such a branch - is that the case?

Seems that way to me.

 

[JohnW2]

"Compliance shall be checked by inspection and by fitting the appropriate conductors."

OK, so it's essentially just a case of "if they fit satisfactorily"?

Seems that way to me.

Intresting. Thankfully, many/most manufacturers appear to have decided to exceed the requirements of BS1363 by using terminals that will accept 3 x 4mm² conductors!

Kind Regards, John

 

[stillp]

Interesting that MK specify 3 x 2.5 mm², when there is room for 3 x 4 mm².