Max # of sockets on 32amp ring main?

[Jim B]

Anyone tell me what is the maximum number of double sockets one can have on one 32-amp ring main?

And how many spurs (with a double socket on each) can one have on one

32-amp ring?

Thank you,

Jim B

[Lurch]

On Fri, 25 May 2007 18:43:01 +0100, Jim B mused:

As many as you want. The limit is floor area, currently 100 sq metres for a 32A 2.5mm ring main.

As many spurs as sockets on the ring, but if you're wiring new then you shouldn't have any. ;)

[Andrew Gabriel]

There are no limits on either count.

It is recommended that a ring not supply power for more than 100m² of floor area. However, this is for general purpose usage, and if you know more precisely how the ring is going to be used, you should take that into account and modify this figure accordingly.

It is recommended that a ring should not have more spurs than directly connected sockets/accessories. This is because a ring normally starts with no spurs, and if it's been extended to the point where there are as many spurs as original outlets, then the current demand for outlets has well exceeded what the ring was originally designed for.

[meow2222]

100m^2 is 10m x 10m, perimeter of which is 40m. Average double socket size around 6" =3D 15cm. 40m/6cm =3D 666 double sockets or 1333 sockets. :)

NT

[Lurch]

On 25 May 2007 11:17:36 -0700, [e-mail] mused:

As I have mentioned before, you talk bollocks at times.

_FLOOR_ area, not wall area.

[PJ]

I must be misunderstanding the calculation. The 100m^2 floor has a=20 perimeter of 40m. Where is the error in his calculation? I accept that he has made no provision for doors in his hypothetical=20 building.

[Lurch]

On Fri, 25 May 2007 19:43:10 +0100, PJ mused:

Height = infinite, therefore, sockets = infinte. Doesn't matter what other numbers you put in, once you multiply them infinitely they are rather high.

Also, a single socket isn't half the size of a double.

[Bob Eager]

You're assuming all one room. There is much more wall area (and potential for sockets) if there are several rooms within that.

There is also the limitation on total *length* of the ring to consider.

[manatbandq]

Who's talking bollocks?

MBQ

[manatbandq]

Some of them are.

MBQ

[John Rumm]

Yup earth loop impedance or voltage drop will get you before you get too far...

84m total length on a type B MCB

[<me9]

There may be interior walls with sockets too. The limit will come when the length of cable used makes the earth loop impedence too high for correct fault clearance.

[Owain]

But isn't that due to cable size?

If one happens to have a cheap source of 10mm...

Owain

[Owain]

Ah, but you can go up and down as well as round and round.

Wall of sockets?

Owain

[Bob Eager]

Which is why I didn't mention the limit! I guess there *is* one, even with 10mm, but it would be a really pathological case if one reached that....

[meow2222]

Lol! Did you seriously fail to spot this was humour? Did the absurd assumptions, absurd conclusion and smiley not give any clues here?

The calc above makes a whole string of nonsense assumptions. Your criticism is not one of them though. If I were a retard calculating on wall area as you suggest, one would have to take into account the 8' or so wall height, which would multiply the absurd result by 8'/3", giving over 40,000 sockets!

NT

PS re doors, I guess you could legally cover those in sockets too :)

[meow2222]

fwiw the calc didnt say it was. Number of double sockets was calculated, then x2 to give number of sockets. This is correct, despite the absurdity of the whole proposition.

NT

[Mike Harrison]

and _really deep_ back-boxes to take it....

[meow2222]

If anyone were crazy enough, the limit would be far higher than 1333. There are 8' or so high walls to cover with sockets, the smallest sockets could be used rather than standard doubles, ceilings and floor could also be covered, baffles could be fitted to the walls at 90 degrees, thus giving many times more surface for mounting sockets, doors could be lined on both sides with sockets - or maybe even made from them! etc etc. However at over =A3100,000 it would be a very expensive exercise.

NT

[Jim Alexander]

that had me worried as I confess I have never taken that into account and one of my ring length must be getting there. I see that Table 7.1 from a previous OSG which apparently specified maximum lengths does not appear in the blue cover edition. Previously Andy Wade has given his usual useful guidance here

I have just got away with it.

Jim A