from 1 single to 3 doubles & 2 FCU's

[d-zoom]

i'm about to extend a main ring at a single socket point. there are two cables for both L and N and three for earth (that's how i know the socket is on a ring - right? - also i've done the continuity test on the two live wires to confirm that).
this is just to confirm what i'm doing is correct - to connect two further sockets I will disconnect one set of cables from the existing socket. this set of cables will go into the first of the double sockets and another will go into the new one. same for the black (neutral) cable.
the above procedure gets repeated for another double socket. from the last double socket cables get connected again with the initially disconnected second set of cables from the original single socket.
Does the above sound right?

i'm also going to run a single spur via an fcu to an extractor hood. in this case there would be three sets of cables going into one of the new double sockets .

any comments would be welcome - especially on the connection method back to the old set of wires - they currently poke out of the wall (solid blockwork) and I'm planning to use a connecting block inside the existing recessed galv. backbox. Can i cover it up under tiles?
Thanks.

 

[ban-all-sheds]

i'm about to extend a main ring at a single socket point. there are two cables for both L and N and three for earth (that's how i know the socket is on a ring - right? - also i've done the continuity test on the two live wires to confirm that).
this is just to confirm what i'm doing is correct - to connect two further sockets I will disconnect one set of cables from the existing socket. this set of cables will go into the first of the double sockets and another will go into the new one. same for the black (neutral) cable.
the above procedure gets repeated for another double socket. from the last double socket cables get connected again with the initially disconnected second set of cables from the original single socket.
Does the above sound right?

I think so - but a picture is worth a thousand words etc, and if you look in the reference topic at the top of the list you'll find diagrams of ring mains.

i'm also going to run a single spur via an fcu to an extractor hood. in this case there would be three sets of cables going into one of the new double sockets .

Yup - or you can connect the FCU directly into the ring as if it were a socket.

any comments would be welcome - especially on the connection method back to the old set of wires - they currently poke out of the wall (solid blockwork) and I'm planning to use a connecting block inside the existing recessed galv. backbox. Can i cover it up under tiles?
Thanks.

No - the junction box needs to be accessible - use a blanking plate. And if you use connector strip rather than the more preferable junction box or crimps, then you should enclose the strip in a box like this:

The only trouble is I'm not sure that 30A strip fits inside them....

 

[securespark]

Yes. Choc Boxes come in various sizes for 2, 5, 15 and 30A blocks.

 

[plugwash]

hmm if there is an existing mounting box in the wall that is a perfectly suitable enclosure for terminal block when used with a blanking plate

no need for a chockbox there

 

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since i don't really want a blanking plate (there isn't the space nor would it look very good above two double socket outlets) i'm thinking of moving both double sockets up to where the existing single back box is (and replaicing it with two double boxes.

this will do away with the need for a junction box and a blanking plate. that is providing the cables are long enough to do that.
in this case the cable is going to run past the second double socket to the third one (below the counter) so as to make the second socket outlet the final in this ring extension, hence doing away with other connections.
does that sound right?

also, there is a fairly solid steel counduit going up from the ground to the existing socket containing the earth wire - the conduit terminates at the socket outlet. do all sockets need this type of earthing?
thanks.

 

[plugwash]

also, there is a fairly solid steel counduit going up from the ground to the existing socket containing the earth wire - the conduit terminates at the socket outlet. do all sockets need this type of earthing?
thanks.

technically no suplementry equipotential bonding is required in kitchens but it is considered good practice by a lot of electricians

as all the sockets are goign to be right next to each other on the ring the corssbonding between their earths will be very good anyway

so just connect that earth wire to one of them and it will be fine

 

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thanks guys

 

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also .... can i cover the cables under the tiles?
the chases are in straight horizontal and vertical runs, but am concerned if somebody tries to screw sth into the wall in the future.
thanks again

 

[ban-all-sheds]

See this

 

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also:

this

found this as well - i suppose it's just a shorter version of the document referenced to by FWL-E (thanks for that).

daz

 

[d-zoom]

problem - the cables poking out from a conduit are not sleeved/bunched together (i.e. there are just two black, two red and the earth ones - but can't tell which black goes with which red etc). i'm assuming that to extend the ring the wires need to be from the same cable going into the next connection point etc.
is there some test i can do to determine which ones belong together?



any views would be appreciated. thanks - daz

 

[plugwash]

if it's not singles in conduit at the CU you can put the wires at the socket into a chock block disconnect one end of the cuircuit from the cu and use a multimeter to find out which 2 wires at the socket give mains voltage on the meter

if it is singles then i would disconnect and seperately chock block wires at another socket then test as above

disconenct all load from the ring before doing this sort of testing

 

[d-zoom]

- thanks for the advice plugwash and everyone else who contributed.

i've got singles at the CU.
the way i understand this is to break the ring at another socket (temporarily of course) to see which wires at my socket still give mains voltage
just to make sure i've got it right. thanks.

also - what would be the problem if they were connected without testing? if they're on a ring live is live neutral is neutral etc

 

[plugwash]

you'd end up with a strangley crossed ring

while this woudn't technically be dangerous it would be a nightmare to trooubleshoot and may fall fould of some unusual reg

as i said the procedure is to remove another socket and then find out which wires are still live at your origianl socket

you *MUST* use something like chock block on the removed sockets when testing live to prevent shorts and warn people who are not electrically competent to keep well away