Is a "ring"-type cirquit essential for the sockets in one-bed flat?

[Axel G]

I had the floorboards up in my one-bed flat today, to check the wiring, and noticed that the socket circuit is not the usual "ring" configuration. It simply has a 2.5 sq.mm T&E cable coming from the fuse box, going to a connector block from which run three spurs: One goes to a double socket in the lounge (for TV, Hi-Fi, etc). One goes to my study (for computer gear, electric fan, etc) and the 3rd spur goes to a socket in the bedroom, and then on to a dual socket in the kitchen. The dual socket in the kitchen feeds a microwave a toaster, a dishwasher, a washing machine and an electric kettle.

Is the above cirquit safe? Or should I add another cable from the kitchen socket going back to the meter, thus creating a proper "ring" cirquit?

What is the point of a ring cirquit, per se? Is it just to split the load between two cables?

Many thanks,

Ax

[Jim Alexander]

whether it is safe or not depends on the fusing

Jim A

[Clark]

Wrong. It depends on the area covered and the expected load as to whether it should be ring or radial. Socket circuits are 30A and cable size 2.5mm. What he has is perfectly acceptable, if worried he could always run another cable from the end socket back to the consumer unit and put it in parallel. A dishwasher shouldn't really be plugged in to a socket! No way of telling if your wiring is safe without pictures or inspecting it. You have no chance of getting "compensation" by claiming it's unsafe, so don't let anyone put that idea in your head.

You should really have a nice new split load consumer unit with MCBs and the new harmonised wiring.

[pete]

Shall I write to AEG and get them to alter their instructions booklets?

[Owain]

No, whether it is *safe* or not depends on the fusing. The area covered and expected load determine whether the circuit is *adequate*.

Wrong. Ring final circuits are 30A/32A and cable size a minimum of 2.5mm.

For a 2.5mm radial circuit to comply with regulations, it must be protected at 20A.

Wrong.

"spur goes to a socket in the bedroom, and then on to a dual socket in the kitchen. The dual socket in the kitchen feeds a microwave a toaster, a dishwasher, a washing machine and an electric kettle. "

This is clearly inadequate for the anticipated use and suggests a very cheap and incompetent job where there may be other nasties lurking.

I hope that "connector block" is a properly enclosed and accessible junction box.

Not quite; the lounge and study sockets are both spurred off the same place, creating the possibility of a high point load which could unbalance the ring.

Where did the OP mention that?

A split load board is only required if RCD protection is needed; if the flat is upstairs then there is not normally a need to consider portable appliances used outside. If other criteria are met then RCD protection is not needed. MCBs are not necessarily safer than cartridge fuses, although rewireable fuses probably indicate the wiring is due for some overhaul.

Why on earth would that make any difference?

OWain

[Mr Fuxit]

messagenews: [e-mail]...

You must be a wonderful electrician to be able to qualify the safety or otherwise of a circuit without even seeing it!

[Lobster]

Since when?

David

[meow2222]

Sockets dont have to be on a ring circuit, but radials need to be fused at 20A at most, and youve got a heck of a lot of load on a 2.5mm T&E radial.

Making part of it into a ring would improve it considerably, with the kitchen feed part of the ring.

NT

[Adrian Berry]

Jim is right:

If the 2.5mm2 is overcurrent protected by a 20A protective device then the circuit is safe.

Furthermore, if the circuit is covering maximum floor area of 50m2, which from his description of a one bedroom flat is reasonably likely, then it is a standard circuit arrangement per Table 8A in the On-Site Guide.

The "connector block" sounds rather suspect - this should be a purpose-made junction box not taped up "choccie block"

However, a circuit should be correctly designed for it's intended function and I can't imagine a 20A circuit would be adequate for a kettle, toaster and washing machine at the same time!

I would install a new 30/32A 2.5mm2 ring final circuit for the kitchen with several extra sockets or spurs for the fixed appliances (one socket cannot be enough, OSG suggests 6 to 10!) and leave the lounge/bedroom/study on a

20A radial.

[Andy Hall]

They have protection at 32A if ring final circuits and either 20A or

32A depending on cable size for radial circuits.

Either may be chosen. If a radial circuit has been implemented and protected at 20A, then as long as there are not contraventions of other rules this can be a safe installation. The sockets on a radial circuit can be connected as required.

That's nonsense. It is not necessariy the case that running a parallel cable from one socket back to the CU will legitimise the circuit as a whole by creating a ring final circuit because the created circuit may still have other non conforming issues.

Nonsense. It can be plugged into a socket or connected to an FCU.

Who said anything about compensation?

There may be wiring to the old colour standard and hence special requirements to indicate the presence of both. The new colours do not inherently make an installation safer.

The consumer unit is another issue.

[Andy Hall]

Actually they can be fused at 32A as long as the wiring is in 4mm^2 for phase conductors, with 2.5mm^2 CPC (i.e. 4mm^2 T&E) and the floor area < 75 m^2.

[Andy Hall]

The best approaches would be to

a) Re-arrange the wiring to form two rings - one for bedroom and study and the other for kitchen with separate 32A MCBs at the consumer unit

or

b) Home run each room's wiring back to the CU with a MCB of 20A for each. This is a radial circuit and you can have multiple sockets daisy chained on it.

This does ring warning alarm bells that the wiring may not have been done properly in other ways so...

- Check for earth bonding wiring to metalwork in the bathroom

- Check that there is bonding of services (gas and water) via earth wiring back to the main earthing terminal at the CU.

- Other "connector blocks". Chocolate block connectors loose under foors are not acceptable.

These problems are not hard to fix if you know what you are looking for and have the information. You have spotted one obvious wrong thing. Obviously if you are not certain, don't take risks.

[Andy Wade]

No, the standard A2 radial circuit protected at 30 or 32 A, using 4 mm^2 cable and serving up to 75 m^2 floor area is also permitted.

[Andy Wade]

Electric ones can be.

[Andy Hall]

Cue. Why do brides wear white? joke.

[Andy Wade]

Your answer can be found on Google, three times.

[Clive Mitchell]

In message , Axel G writes

That is a pretty high load in the kitchen. (As always.)

If this radial arrangement is wired in 2.5mm cable and protected at 16 or 20A then it's safe (quality of "joint" and wiring permitting). If it's fused or otherwise protected at 32A then the cable may be running hot under full load and the load needs spread. With such a high load in the kitchen alone I bet the fuse has been wired with 32A wire or a 32A breaker has been fitted.

At the very least it would be better to give the kitchen it's own 20A fused supply, but that's not a lot given the amount of appliances even given the short duty cycle of things like toasters and kettles. A new

32A ring main and a few more sockets would make life in the kitchen more tolerable.

The point of a ring main is to spread the load between two smaller cables allowing easier wiring and termination then a heavy radial circuit.

[tinnews]

I think the original intent when they were first introduced into the Wiring Regulations was as a means to save copper.

[Lurch]

On 27 Apr 2007 08:05:54 GMT, [e-mail] mused:

Ring mains were originally introduced as an easy way of converting the very common 15A radial circuit into a 30A circuit for being able to plug new fangled electric heaters and such like in. You'd do this by running a cable from the end of the radial back to the consumer unit and sticking a 30A fuse in it rather than rewiring the whole circuit.

[Andy Hall]

One has to keep an eye open for opportunity...... :-)