3 cables ring main at CU...HELP PLEASE?????

LLOYDSPARX · Mar 14, 2011

hi guys,

recently i have been working on a ladies 10 year old 3 story house. I have added 8 new circuits (sounds crazy i know), 2 cookers, 2 showers, 2x 20a underfloor heating circuits, 2 ring mains. This has meant that I have to fit a new 15 way 17th edition consumer unit.

The customer at first said she had the original certificates, now she says she doesn't which means i need to issue a full EIC right and periodic on the old?

While carrying out a Periodic on the existing wiring, i noticed there is only one ring for the rest of the house (13 sockets) and at the consumer unit this circuit has 3 cables. I know you all must be thinking its a spur off the CU but... i disconnected all 3 legs, belled across them all with the steinels and they all still bell out from one to the other. I was hoping that one would just be a seperate radial put in with the ring main circuit but its not, they are all still part of the ring.

Would it be a good idea providing they test out okay to place 2 of the 3 legs in a junction box in the wall behind the CU and run a leg back to the board (so there is two not three)??? no one will know i was the one to do it if i were to use some old colored cable from the JB. Or is it okay to have 3 legs at the board? if so how would you go about testing this? Also non of the wiring for the rest of the house is accessible, it has tongue and groove floors with carpets and 3 steels across each room. If there are any problems how on earth could i rectify them and if i can't what do i do about signing off the 8 circuits i have added??? Please express your thoughts guys!

Engineer54 · Mar 14, 2011

I think your going to have to do a lot more investigation to start with!!! No you can't do as you suggest, what on earth are you thinking?? Start by checking each socket outlet, if necessary disconnect all cables on this circuit and trace as far as possible socket to socket and back to the CU.

LLOYDSPARX · Mar 14, 2011

yeah i was thinking that incase there are any interconnextions or bridges, but would that really be so bad to do if it still tests out okay. i know its not good practice but if you go into a house to do a periodic, you wouldnt see the JB in the wall anyway. the whole jobs a nightmare tbh, i wish i didnt take it on.

RWJ · Mar 14, 2011

As Eng.54 stated.. I don't think you've any option, split the ring (or what you think is the ring) and go from their, just follow your 2391 training

Geordie Spark · Mar 14, 2011

Would it be possible to fit a new CU just for the new circuits & leave all the old stuff alone?

LLOYDSPARX · Mar 14, 2011

yeah well am going to give it a shot then, whole circuit is a shambles though. as i said also, i can't alter anything, only disconect the leg from a socket, thats if i find it and it doesnt mess up the rest of the circuit doing so. JB would be my last resort, and would that likely to not test out properly?

LLOYDSPARX · Mar 14, 2011

@geordie spark. do you mean have two consumer units? do most meters cater for two sets of tails then? that would be a lifesaver, but wouldn't the existing circuits still need a PIR considering there is no previous results. there must be some results somewhere with building control or sumet, the place is only 12 years old and its a 500k house

Geordie Spark · Mar 14, 2011

LLOYDSPARX said:
yeah well am going to give it a shot then, whole circuit is a shambles though. as i said also, i can't alter anything, only disconect the leg from a socket, thats if i find it and it doesnt mess up the rest of the circuit doing so. JB would be my last resort, and would that likely to not test out properly?

Personally, I think the JB idea is a big no no & for me if it's in the shambles you say it is, there would be 2 options - either a complete rewire, or leave the old stuff alone & fit the new CU to the new circuits.

Geordie Spark · Mar 14, 2011

LLOYDSPARX said:
@geordie spark. do you mean have two consumer units? do most meters cater for two sets of tails then? that would be a lifesaver, but wouldn't the existing circuits still need a PIR considering there is no previous results. there must be some results somewhere with building control or sumet, the place is only 12 years old and its a 500k house

There's nothing to stop you putting the tails from the meter into a Henley block then take 2 sets of tails from that - 1 set into the old CU & the other set into the new one.

LLOYDSPARX · Mar 14, 2011

okay matey well i think thats my only answer then, would make life so much quicker and easier (stressfree). yeah i wasnt sure about the JB either, that would just have been if i had no other option. nice1 bud!

Phil · Mar 14, 2011

LLOYDSPARX said:
hi guys,

Would it be a good idea providing they test out okay to place 2 of the 3 legs in a junction box in the wall behind the CU and run a leg back to the board (so there is two not three)??? no one will know i was the one to do it if i were to use some old colored cable from the JB. Or is it okay to have 3 legs at the board? if so how would you go about testing this? Also non of the wiring for the rest of the house is accessible, it has tongue and groove floors with carpets and 3 steels across each room. If there are any problems how on earth could i rectify them and if i can't what do i do about signing off the 8 circuits i have added??? Please express your thoughts guys!

? accessible locations? no not acceptable .
using old colours? no

DurhamSparky · Mar 14, 2011

in all honesty i think this guy is a wind up merchant!!

with out wanting to offend you and cause a stir how long have you been an electrician serious question as the questions your asking sound that of a novice diving in way to deep! if you cant get your head around the current layout / rats nest then i woul do as Geordie spark says and fit a secondary unit from henly / lucy blocks.

and the existing installation does not need a PIR if there are no records around for it but you giving it one is good practice.

and no Building control wont have any paperwork from the job as they dont get sent that info

Richard · Mar 14, 2011

Is their much loading on the circuit? If you can't garentee it's a good ring, then why not just treat it as a 2.5 radial and fuse it to 20a?

RWJ · Mar 14, 2011

DurhamSparky said:
in all honesty i think this guy is a wind up merchant!!

with out wanting to offend you and cause a stir how long have you been an electrician serious question as the questions your asking sound that of a novice diving in way to deep! if you cant get your head around the current layout / rats nest then i woul do as Geordie spark says and fit a secondary unit from henly / lucy blocks.

and the existing installation does not need a PIR if there are no records around for it but you giving it one is good practice.

and no Building control wont have any paperwork from the job as they dont get sent that info

My point about the follow your 2391 training.... I sure he's as qualified as you or me steve....
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