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  1. C

    Fault finding ring final RCBO

    Done a condition report on a old mains board, everything good apart from ring final, got 0.55 nn 33.7ll and 3.8 on ee, changed board to main switch and rcbos, carried out a full accessory swap on all sockets and fuse spares in house, found some bad practice, twisted lives, n and earth's, no...
  2. W

    7 core NYYJ cable to extend ring final circuit?

    Hi, Extending a ring final circuit off a socket in the kitchen through the wall into the shed on the other side. I already have 7 core NYYJ 2.5mm cable and I was wondering if I could use that to go through the wall to a J/B then connect to singles in conduit which would add about 4 meters in...
  3. J

    Diversity on a Ring Final

    Hi there, I'm just trying to get myself into cable calc and my first hurdle is demand and diversity. I understand the majority of what is coming across in tables A1 and A2 OSG but I'm just struggling to clearly understand what I should be using for demand on a domestic 32amp ring final...
  4. samsingh

    UK Am2 - Ring final circuit

    Hi, I've sat my am2 practical today. I have a question about the ring final circuit hopefully there is someone who can relate. Is it crucial to wire the ring final a certain way? Ive bought 2 legs out, one goes into my closest socket which went down a bit of conduit and the other leg goes to...
  5. P

    UK Extending/breaking into ring final circuit

    I need to install some extra sockets in a kitchen. It's a single story ex-commercial kitchen. All the wiring is in singles in steel trunking in the loft space, with drops through steel conduit to the various sockets and switches. I want to install an additional 6 sockets under the worktop for...
  6. marconi


    Over the last few days I have been stuck indoors because of the rainy weather. To pass the time I cobbled together my simple idea for a FRC live conductor break detector, ie break in L or N. I also have a working demonstrator for detecting a break in the cpc but I will/may post that another...
  7. Sparksaflyin

    Dual board with no earth on final circuits

    Hi guys. Need to change the fuseboard at my parents house but none of their final circuits have a cpc run to them. Obviously have an earth on the main incoming so I can get a 16mm earthing conductor up to my new 18th edition metallic consumer unit but they don’t want a rewire so none of the...
  8. R

    Extending ring final circuits

    Hi. I have a CU move to do - around 5m from current location. There are 10 circuits, 4 of them ring finals. I'm considering whether to extend the rings 'as are', or to split the rings somewhere in their approximate middles and extend them to separate RCBOs as radials, the aim being to reduce...
  9. D

    Radial final circuit

    Hi guys, just started rewiring my house, and noticed the sockets in the attic wired in radial instead of ring. Can I leave it in radial? There are only 2 sockets up there, unlikely there will ever be much load on it. I was thinking of wiring it 2,5mm2, (as it is now) on a 16A beaker. Any...
  10. S

    Supply and final circuits for stables.

    Hi all, just looking for advice prior to a potential upcoming project supply stables for horses. The supply characteristics into the main house is TNCS and the stables are located approx 40m away from the building. I am thinking of putting a 1w non-rcd protected consumer unit at supply end...
  11. Marcus Vaughan

    Shaver Socket from a Ring Final

    Hi All, A customer has asked for a shaver socket to be installed in his bathroom. The only issue is that there is no lighting circuit available (loft conversion above and no access to the eaves). His idea was to come off a socket in a bedroom on the other side of a stud wall to the proposed...
  12. Sparksaflyin

    clever ways of ring final test without removing spur fronts??

    Morning fellas. I know from regular visits to this website that we have some rather intuitive Sparkie’s on here so I thought I’d join in the fun. I’ve got a rather basic question to start with but also where some of you can hopefully show your tips and tricks. Im currently working on a...
  13. Dan

    18th Edition Training Course - Online with Offline Final Exam

    18th Edition Training Course - Online with Offline Final Exam Level 3 Award in the Requirements for Electrical Installations BS 7671: 2018 Online 18th Edition Course – Available From July 2018 This course has been developed with the aim of enabling the candidate to demonstrate that they are...
  14. KeenPensioner

    Can't figure ring final r1 + r2 divided by 4

    Hi...keen amateur here......don't crucify me for asking!! I understand Ohm's law and I understand the mechanics of measuring end to end on ring final and then joining incoming live to outgoing neutral etc, and I know that this configuration gives a figure of 8 (in fact can be straightened to...
  15. J

    Hand dryer off ring final

    HI everyone, Is it acceptable to wire a hand dryer from a ring final in to a 13 amp FCU. The ring main in question has 30MA RCD protection. Or, is it best to wire a new radial circuit for it?? There is a socket I can spur off that is easy to get to. Thanks
  16. Marcus Vaughan

    Power to an Outside Office - Spur from Ring Final?

    Hi All, Just looking for some reassurance on a job I've looked at today. My status is that I am trying to stay within the realms of 'Minor Works' until I get a bit of experience under my belt. Conscientious decision - but everywhere I go it seems that notifiable work is needed as well...
  17. Andy78

    18th edition final changes released by IET

    Changes in the 18th Edition IET Wiring Regulations - IET Electrical -...
  18. L

    Final Circuit Protection

    Hi Everybody Why fuse is no longer use in Final Circuit Protection. Instead, Circuit breakers are used. So far, I know that CB is more sensitive than fuse. Can someone depicts any reason and their respective curves. Thanks
  19. Marcus Vaughan

    High(ish Zs and extending ring final question.

    Hi all. Love the forum by the way. I do have a question though... I have just visited a house (on a Sunday!). Customer is asking for additional sockets onto 32amp ring final. Circuit is 30mA RCD protected. Wiring is 2.5mm/1.5mm tinned copper. Thought I’d better do a live Zs test. Zs = 1.29...
  20. B

    Fault finding on ring final circuit

    Fault finding on ring final, is this the readings you would expect to achieve and are these the correct way to find them thanks
  21. 7

    Ring final testing question

    Testing my extensions wiring today and noticed cpc fails continuity. Howevery I have continuity from outward leg to main earthing bar in CU Any ideas how ?
  22. T

    R1 R2 socket test on Ring Final Circuit with megger leads

    So with megger leads they are not too happy in a kewtech socket tester so what do you do when you want to do this use kewtech leads on the megger? The megger leads clearly do not fit into the kewtech. Just use the plug lead?
  23. D

    SY cable for distribution circuits and final circuits

    Hi all, Just a question relating to SY cable and the use of SY cable. My boss his carrying out a EICR for a industrial premise and coming across a lot of SY cable. These cables are used for final circuits and distribution circuits. I know that BS7671 list SY cable as non - standard cables and...
  24. J

    EICR code Split cpc on ring final circuit

    lost continuity on cpc of ring circuit, live and neutral fine all test fine. C2,C3,FI ?
  25. M

    Faulty MCB. Problem isolating ring final circuit at CU with MCB

    I am planning to move a socket outlet. The CU is largely unlabelled so don't know which 32 MCB to switch off. There are 2 x 32a MCB. All other mcbs are for lights (6a) and a dedicated immersion (16a). To isolate the circuit, I tried switching off the first of the two 32a mcb which isolated some...
  26. Cadgey123

    Scrap the Ring final circuit

    After coming across countless faults in domestic premises regarding ring final circuits, I reckon they should scrap em... Gets frustrating when you go to check continuity and there is nothing between each leg. Or you get a call to check a burning smell from the C.U and once again a broken ring...
  27. R

    Low IR ring final circuit

    Testing a ring final circuit today. R1+R2 is fine, same as end to end r1 rn and r2. However IR test is coming back 1.87M ohm. I split the circuit and located a section (one side of the ring is clear >999). The customer doesn't want any walls or ceiling touched. As this is greater than 1M ohm...
  28. haptism

    Ring final install method query

    Hope someone can help. When finding the cabling current capacity for a ring (wired in 2.5), would you use the data for 4mm in either/or table D5 of BYB or table 7.1 (11) in the OSG ? As the ring circuit is in effect 5mm ! Looking at the OSG ref methods; a 2.5 with ref method 101 says 17A...
  29. Soulsurfer

    Ring final & Radial circuits off one mcb ?

    Another straight forward job today has turned out to be a right mess once again so I thought I'd get some thoughts on the following before I start ! So an old MK LN59 board, feed to garage sockets on a single 2.5mm t&e from a 15A mcb and also spurred to feed a boiler on S plan, Next ring final...
  30. CDB

    Starting point for discontinuous earth fault on final ring.

    Hi all, I have a 32A Final Ring Circuit that I have swapped a single socket to a FSU for an outside light. I'm now testing it and finding it has a discontinuous earth - I'm also kicking myself for not checking from the off but we learn. Anyway from the attached image you should be able to see...
  31. M

    PV Final Design and Permit Packet Option?

    Hello Everyone, I currently work for a startup solar company as a proposal generator. As of now, I create the proposals using Aurora and then outsource to a partner for fulfillment - site survey, final design, etc. I'm looking into keeping the final design internal, but not sure what options...
  32. D

    How does ring final circuit work

    Hello all I used to believe that the power of circuit is running from live to neutral,then go back to the distributor.But when I see ring final circuit,I get confused...I know the power goes from both side of live cable,then it goes back to the circuit breaker? Sorry about my poor...
  33. incursio

    Hi Folks

    I'm a final year electrical apprentice, I've been actively working in the industry for a couple of years now, I'm was brushing up on my electrical knowledge, when I came across this site.
  34. A

    ryefield board confusion

    i am only a second year apprentice so please bear this in mind if this question comes across as stupid.. i am currently working on a site where one property (old pub) is being converted into 8 seperate flats, and at the minute we are working on the power distrobution to each individual flat...
  35. D

    Final Ring Test during EICR

    Guys non domestic stuff here but is it true that you don't carry out ring final tests on EICR. Or is it that you don't have to and done do it as a matter of course anyway or do you charge extra for doing stuff not needed. I'm of the opinion of its not much extra to do it then I'll just do it...
  36. M

    B type breakers with in line UPS

    Hi I'm hoping that someone can help. I am adapting some circuits which are supplied via an in line ups. At present, the ups supplies a 72 way db and the final circuits are supplied from the DB. This is a laboratory research environment and it is expensive (about £20k a time) when they...
  37. L

    Volt drop question

    Hi I've got a question regarding volt drop. When calculating volt drop to a 3 phase distribution board do I use 230v (11.5v) or 400v (20v) The board I'm attempting to put a cable to is 75 meters away. Design current 100A From TABLE 4D4A Cable selected = 25 mm² For 25 mm²: mV/A/m 1.75 for 230v...
  38. A

    2 certs one job

    Hiya From a 3 phase board i have pulled a submain in to feed a 6 way single phase board and wired my final circuits from there. But i have also wired a single radial to feed a socket from the 3 phase board via a rcbo. How do you cater for this lot on test sheets? Would you do a...
  39. J

    ring circuit why ?

    why do people use a ring circuit? i understand that the cable for example 2.5mm twin and earth can carry more current in theory another reason i can think of dont know if its why is the circuit may require a heavy use of socket outlets e.g an office using computers etc... but what other reasons...
  40. P

    supplementary bonding and rcd protection

    Hi, a recent PIR has picked up no RCD protection and no supplemantry bonding to pipe work. Am i correct in saying if all circuits to bathroom are protected by RCD then supplementary bonding is not required?
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