Ring Final Circuit Testing for Sockets Wired in 2.5 Twin and CPC Cable (Twin and Earth Cable)
Student training aid for how to carryout a continuity of a ring final circuit and polarity. Using a MFT Megger tester set to the ohms scale. This video follows the 3 stage required to prove a ring final circuit is wired correctly as well as carrying out the calculation required. The circuit is wired in 2.5mm2 twin and CPC cable (twin and earth) as it is in a domestic installation. Sometimes in industry this type of circuit is called incorrectly a ring main circuit.
Things of note: finding r1, rn, r2, R1 + Rn, R1 + R2, 1.67 ohms and proving one of the sockets is a spur from the ring. After completing the test the conductors are returned to the correct torque setting with in the consumer unit.
NOTE - at times during the video I state some of my reading wrong by adding anther zero on to the value. the subtitles are correct as are my calculations and my final reading recorded as R1 = R2. Hopefully you can forgive a oral slip ups. Massive thanks Gaz
== 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 - How to test a ring circuit
00:52 - Consumer unit layout
01:03 - Identifying the legs of the ring circuit
01:56 - End to end test r1, rn and r2
02:31 - The rule of 1.67 times greater
03:05 - Reading for r1, rn and r2
04:12 - Calculations for R1 + RN and R1 + R2
04:40 - Linking opposite line to opposite neutral
05:29 - Testing at every socket outlet
06:50 - Finding a high reading on the ring circuit
07:38 - Spur from the ring final circuit
08:31 - Linking opposite line to opposite CPC
09:10 - Testing at every socket outlet
10:22 - Finding and recording out highest reading in ohms
11:00 - Using a torque screwdriver for the connections in the consumer unit
Understand and Carry Out Terminations and Connections of Conductors 5357 107.
🔵 How to Test a Ring Final Circuit - Ring Main or Socket Circuit - Ring Continuity & Polarity Tests • How to Test a Ring Fin...
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
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How to Test a Ring Final Circuit - Ring Main or Socket Circuit - Ring Continuity & Polarity Tests kzhead.info/sun/iMmsiayOqox6YH0/bejne.html
this channel is literally getting me through my second year
Loads more content to come and thanks for the support 👍. If you haven’t already checkout online the eFIXX appreciate hub as well as my other KZhead channel eFIXX for more content. All the best. Gaz
This is probably the most comprehensive video on RFC testing Ive seen. Very simply explained and all the practical pit falls in a real test enviroment covered. Too often explainations by so called experts miss out important points which in my opinion lead to electricians omitting this important test because they dont understand the underpinning principles. Well done sir !
Wow thanks for that 😁. All the best and thanks for taking the time to comment Gaz 👍
Well said
Brilliant
Great resource. Clearly and thoroughly explained. I'm revising for my 2391 and these videos really help. Thanks.
Hi. Thanks for commenting and watching glad they are helpful sorry about the sound quality of the early ones 👍 Gaz
Excellent explanation, the only thing i think at 8.54 mins into the video the reading is 0.3, not 0.03 ohms
GSH Electrical always makes the tests clear and concise, great work.
I work for niceic and this is a well described educated video for those who might be starting to come in to this industry well done mate
Thanks for the support 👍😁
Great video - Having been a high voltage engineer for the past thirty years, and when my friend told me of an issue with her socket ring intermittently tripping, this video reminded me of just how to test efficiently an LV ring circuit ....quite humbling how big a variation there is between testing on high voltage networks and low voltage ..... no not really ..safety is always first .. no matter what the voltage
Thanks for watching and taking the time to comment Gaz 👍
Great video especially explaining the "divide by 4" logic but I was confused at 8' 45" when you said the reading would be "nought, point nought three" thinking I had missed something, but they you later came back to the calculated value of "nought, point three" so assumed that this was a "verbal typo". The man who never made a mistake never made anything. Thanks for the insight.
Great Video GSH thank you for the pratical demonstration, and helpful information on the calculations
Very well presented clear and concise demonstration well done thanks keep the videos coming
The Best and most thorough Video...Love the videos GSH keep'em coming...wish i had enough work to practice all this ...Jeezz
Hi. Wow thanks for the kind words and watching GSH Electrical (Gaz) 🙌
Thanks for sharing I’m not an electrician but an industrial designer engineer and it useful for me to know about installations testing. Although I would avoid rings of any kind it’s really good to understand the principles and testing. I wish all electricians were trained by you as it’s a good day if I find the electricians have connected all three phases and as for rotations don’t even ask. Best regards Chris.
Best one yet. Sitting my AM2 monday and this cleared it up thanks
As usual a superb lesson from Gaz. The mans a legend
ewb69 thanks for the support. Gaz 👍
Amazing explanation!
== 🕐 Time Stamps - Cut to the action 🕕 ==00:00 - How to test a ring circuit 00:46 - Consumer unit layout 00:58 - Identifying the legs of the ring circuit 01:56 - End to end test r1, rn and r2 02:30 - The rule of 1.67 times greater 02:59 - Reading for r1, rn and r2 04:12 - Calculations for R1 + RN and R1 + R2 04:40 - Linking opposite line to opposite neutral 05:29 - Testing at every socket outlet 06:50 - Finding a high reading on the ring circuit 07:38 - Spur from the ring final circuit 08:31 - Linking opposite line to opposite CPC 09:10 - Testing at every socket outlet 10:22 - Finding and recording out highest reading in ohms 11:00 - Using a torque screwdriver for the connections in the consumer unit
thank you, you are amazing and very helpful. I wish you the best in this life and hereafter.
Thanks 👍🏻
Excellent video again as ever. Thank you for explaining the reason the equation is devided by 4 I have watched a few videos in this and it was confusing me as no one really explained it. Thanks
👍
Fantastic, your video was Faultless and I loved the inclusion of the spur socket at the begining without letting than one out of the bag when testing. Note to sure I would have not made a comment informing your viewers that on the Form it is important that whilst showing the correct readings taken from the Ring Circuit that it is worthy of note that the Higher than Normal Reading was taken at the Spur from the Ring Circuit. Sorry but I am old school and believe in making everyting that bit easier for when the next guy shows up and he is not scratching his head. Mr Spence Eng
Great video and easy to follow Thanks
Great and detailed explanations. Well done GSH electrical.
Thanks 👍
Just for those that might be confused, yes he has said the incorrect readings but the process and stages are perfectly explained. How many perform it in this way on an EICR?
Nice video, in 40 plus years on the tools I’ve never ever seen another spark carry out the full test on a rfc
Hi. The testing is number 2 in the test sequence in BS7671. Thanks for coming back and have a great bank holiday 👍 Gaz
That was clearly explained, thanks.
Thanks for sharing these videos. They're proving to be an extremely helpful tool for my studies.
+C Sween Many thanks for your kind words. More uploads to come all the best GSH Electrical
Thanks for sharing it with us. I'm watching you from Ghana
Thanks for watching in Ghana 🇬🇭 👍
Very helpful 👍🏼
Very informative and well explained tutorial. On stages 2&3 do you need to null the plug leads to the mft?
Love the vid Gaz, 'Very Delia" as my science teacher would say (that is to say step by step and simple to follow, like her recipes....)
Massive thanks for the wonderful comment. Gaz 👍
Not problem squire, it was your vids (along with most of your guest speakers - CJR etc - that made me want to get in the trade
This man is great.. Respect
Great explanation thank you and can I get to know the categories of final circuits please?
Great video- possibly best RFC testing video I've seen (I think I've watched all of the ones on KZhead too!!) Any plans to do the other tests in this way? Thanks!
+Joel Hatswell Your very kind. I am back at work now but I only work part time. I am trying to do a video a week which will including testing ones. Hope this helps GSH Electrical
Thanks for the video 👍
As a home wiring diy’er I found this very interesting. Luckily there is not too much to it. Just using resistance to check that all is well. Simples. I like wiring because you can work most stuff out if you think about it logically. Thanks for taking the time to make your video.
Thanks for watching and commenting. All the best. Gaz 👍
Excellent video Gaz
ToxicmakerYt thanks 👍
Is there a playlist of all the tests you've done both Dead test and live. That would be really helpful if there is
Hi. This would help kzhead.info/channel/PL2Ea5r9gxUUdVgYrSiQG7RQDBOcUWjCcX.html Thanks Gaz
Perfect 👍
Thanks for sharing
All good stuff Gaz as usual...On certificates it is also worth noting (and I think there should be a dedicated space for it) that the high readings taken, and those recorded on the certificate, for R1+R2 and R1 +Rn were at a spur...because mathematically they are out of allowable tollerance, as you prove in the video. ...At first glance of a certificate...Say... on a EICR, the inexperienced may wonder what is going on.... On a different note ...the 1.67 ratio between Line and CPC is great ...BUT... only on 2.5mm Line and 1.5mm CPC...it varies with the cable size....10mm or 6mm cable (line/neutral size) ..a different ratio mathematically exists between L N to CPC, as I tried to explain to someone recently...and they were having none of it...telling me I was wrong.....then a few days later.....I was correct....They read a book..ha...none the less they read and now know...job done.
Hi. Totally agree we annotate the paperwork at Level 3 with all sorts of extra information. This was a level 2 introduction video to test ring final circuits. Thanks for your Quality input Gaz
The 0.05 Ohm variance only applies to step one, the end to end testing. The sockets tested at step 2-3 should be the same reading although allowances can be made for age and usage. (GN3 643.2.1 2.2b 2.2c) or OSG.
Hi Gaz, i have a question: When joining opposite ends on the ring Lets say r1 to rn Will this pick up reverse polarity at a socket ?
Excellent video once again. A couple of questions... where there are a number of spurred sockets whats the best way of finding the socket(s) they've been spurred from? Also, if there's found to be multiple loops or interconnections would they have to be rewired so as to be part of the main ring?
+Jake Chattey Hi. The fault finding for multiple spurs is one done on instant. Think which socket looks most likely to have been used to spur from. You can also drop the front screws off all sockets but it still could be a spur from a joint box under the floor. If you find the socket the spurs start from the easiest thing to do is put a fuse connection unit in (fuse spur) making the spur sockets fused at 13 amps. Thanks GSH Electrical
A semi-related Q. Is there any sure fire way to check which type you have. Our house was rewired in 1987. I see a single socket which has only 1 wire and I can't tell if it's just a spur off the main ring. The double socket beside it has two wires. So the single seems liked it's spurred from that. Or it could just be the end of a radial as it's the furthest point away from the consumer unit on the first floor. I've checked the circuit breakers for the mains and they're all rated for 20Amp.
Hi, have you included resistors behind the board to get those resistance readings? Moreover, I have seen the working bench that your students are working for the cable tray bend. What kind of bench is that? Great videos keep doing them. Congrats on your work from a fellow electrical tutor in Cyprus.
Hi. Thanks for the positive comment and yes the board has resistors built into it. All the best GSH Electrical 👍
Thank you.
Please I can see from the consumer unit, the ring circuit are terminated in the same point. Is that how it should be done because I was thinking since the neutral block terminal or link and the earth block terminal or link are not splitted, it can be separately. Any explanation please
as an additional question have u done a video explainong settings and connecors on your test meter thanks
Hi again try this link it my help kzhead.info/sun/qrOrd6Wroaqdmnk/bejne.html Thanks for watching GSH Electrical
I understand that when you increase the cross sectional area, the resistance is halved, but in this example how is the length halved when the two conductors are put into each socket can someone help me understand please
Two questions, please - I am a layman when it comes to this . . . just interested in learning. I am used to the reference 'Ring Main' . . . why is it 'Ring Final Circuit' now? What is 'final' about it? Is there any practical difference between the reference 'earth' and the reference 'CPC'? If not, why use a different name? Thank you
Just for information. What is the a _typical_ ohms reading of a final ring circuit, that is L to L or N to N, for a typical UK house: *1)* the downstairs ring? *2)* the upstairs ring?
brilliant.
In my house I'm getting a reading between r1&rn and getting reading between conductors in stage one but getting 0.00 in r1 and r2 what could it be
Hello how r u. I hope you’re good. I just want to know . What is the length of this circuit. If I’m right the length of this circuit is 22.5 Resistance/meter or (R1+R2)/metre (m one/m). Please reply me as soon as possible. I’m waiting to your answer please. Thanks.
Hi Are you using resistors in the sockets as the length of the Run is quite short
Hi. Yes we have added resistance to the circuit conductors 👍. Thanks for watching and commenting Gaz
Is there any tutorials on how to do this when there's a spur off the ring main mcb
Is there an IR test done on the ring or is this it?? Appreciate the upload btw. Aussie spark here. We don't do much if this. I'm over in UK now. Doing 1th plus test this year. These clips are very useful
Hi and thanks for supporting and watching. Yes this circuit requires an installation resistance test (IR). Have a look at my testing playlist 👍. All the best Gaz
Hi gaz are these the 3 tests a sparky would do after say wiring a new kitchen ring final sockets, or is there other tests to do to make sure the sockets are working and safe 👍 cheers
This is one of many tests required after wiring a new ring circuit 👍.
@@GSHElectrical cheers gaz 👍👍
Do you think the readings can change from disconnecting test leads after testing at board and using the plug at the socket? There’s isn’t a tool that can null the plug is there?
hi the first testat join block would u have to put both probes in live side or could u do on blue side
Hi. The opposite line and opposite neutral are linked in one connector block and the reverse in the other connector block. Then the measurement is take with one probe on one block and the other probe on the other block. Hope this help GSH Electrical
Please I wanna ask a quick question, you could see that from your continuity test of the ring circuit, the phase or Live conductor and the neutral conductor has the same reading but that of the CPC or earth conductor has a greater reading value as compared to the other two even though it has a smaller diameter of 1.5mm. Please why is it so.
Smaller conductors have higher resistance 👍
good video
Hi, is it normal to get no resistance at the CCU while doing stage 2 of the ring final test? While doing stage one I did get resistance from all conductors, but at the CCU during stage 2 there was 0 resistance and at the socket outlets I had a reading of 0.35 ohms. Thanks
Hi. No you should get the same reading at the consumer unit as you do at each socket on the ring during stages 2 and 3.
Hi Gaz so although you connect opposite lines and neutrals u still connect to both live parts of connector block
Hi. Opposite line and opposite neutral in the same connection 👍. Thanks for commenting and watching Gaz
@@GSHElectrical Yes I saw that but looks like you probed both live screws
@@shaunbeard593 Doesn't matter as leg 1 live is connect to leg 2 neutral & leg 2 live is connected to leg 1 neutral so you have your conductors connected to give you your R1+RN readings
@@andrewrea4233 it threw me a bit as probes were on both live wires. Fairly new to this so was just confirming thank you
Do you have to do it in the board or can you do it in any socket in the ring circuit?
Hi Gaz, my R1+R2 readings are always higher than the Zs readings. Whether that's ring circuit, shower, boiler, etc. Why is that? And is it ok to have a higher R1+R2 readings? Thanks
How would you know what the manufacturers torque recommendations were if nobody had left a leaflet in the CU?
Hi. Electricians tend to keep copies or use the internet to find out. Thanks for watching GSH Electrical
Hi Has this test got to be done at the board ? Why can't you take a socket front off and do it there.
+Roy Kirkham This test is carried out at every point on the circuit to prove all sockets are on the ring and we don't have multiple loops, interconnection or a run on non fused spurred sockets. The first test at stage 2 is carried out within the consumers unit confirms your calculation but with this figure of eight test is one of the points on the circuit. All points (socket) including the consumers unit have exactly the same amount of cable (resistance) so they all should have the same reading during the test if they are on the ring. The video accompanies my lesson(s) and would be an hour long if coved all points. Sorry this time I cannot offer more help GSH Electrical
I think what RK is getting at is can the crossover be carried out at a socket ? It certainly would be easier identifying the legs for crossover especially when you’re confronted by a congested untidy boards. The rest of the test can then be carried out at each socket as normal. I would probably remove the neutrals and cpcs at the CU and put them in separate connectors as a precaution.
should have the socket outlet switch to be ON or OFF? during the test
Hi. You should operate them during the test and leave them on for your insulation resistance carried out afterwards. Thanks for watching GSH Electrical
Hi, where can i find the list, in order, of all tests required please. Cheers
On-Site Guide is a great starting place 👍.
maybe I'm being think and totally missed something, but at the start of stage 3 at 8:28 your R1+Rn you have 0.43 + 0.77. Is this now a new calculation not continuing from the step 2? I'm just curious to know where the 0.77 came from. Thank you
Hi. Stage 3 is R1 + R2 and not R1 + Rn Hope this helps and thanks for watching Gaz 👍
R2 is the CPC which is 1.5mm (squared), as opposed to the Line and Neutral which are both 2.5mm (squared) (Twin & Earth). This means that the CPC should have a higher resistance seen as though its 60% smaller than the line and neutral.
Why is the mathematical relationship between 2.5mm squared and 1.5mm squared 1.67? Is this worked as a ratio of 5:3 and therefore 1.67? Thanks.
2.5 divided by 1.5 = 1.67.
Why do we need this test? ..what does it show?
When you are doing stage three testing and the meter displays 0.3, you are saying this is 0.03. Do you mean this or is this a mistake?
I apologise 👍. Thanks for watching Gaz
GSH Electrical thanks, wasn’t meant to be clever it’s just I’m interested in such things and needed it to be clear in my head. Whilst writing, a question for you 😀. A high voltage igniter pack had written on it 33% ED in 3 mins. What does this most likely mean?
How fill certificates
if 2.5mm2 is rated to a max current of 25amp why is the circuit rated at 30amps? If any part of the ring is broken it is a good possibility that no fault will be noticed by the user.
If you record o.52 would that not fail the test as it is outside the 0.05 ohms
More help How to Test a Ring Final Circuit - Ring Main or Socket Circuit - Ring Continuity & Polarity Tests kzhead.info/sun/iMmsiayOqox6YH0/bejne.html
Hi Gary isn't you end to end on r2 a little high 0.43 x 1.67 = 0.71 ?
We have built in resistors in the rig... but yes you are correct if the cpc is 1.5mm2
@@GSHElectrical Thanks for clearing that up thought i had missed something ! Perfectly explained video Many Thanks
Why is the LCM 4
Please why is it that the CPC is largest cable used when burying earth...
I'm looking for a course in electrical installation and testing. I'm 23 years old. Any ideas? Many thanks.
@gsh ekectrical
GSH ELECTRICAL
What's "final" about a Ring Final Circuit?
Why do you have to make a ring in GB? I´m from Germany.
Great question.... I personally don’t like them... Gaz
We don’t have to
at 2.40mins the instructor states 4.3 when it should be .43 of an ohm.
My question is this...how many socket in one 220v circut
Hi. In a domestic dwelling you can have as many BS1363 socket outlets as you want however the Limiting factor is the floor area. For an A1 Ring Final Circuit 100m2 for an A2 radial socket circuit 75m2 and an A3 radial socket circuit 50m2. There are other considerations but these are the basic rules thanks for watching GSH Electrical 👍
crackin video
Great name 👍🏻
At 8.44mins he should have said reading will be nought point three but he said nought point nought three !!!
Its confusing how it proves polarity. I guess just accept it. Thanks for video
It proves the line, neutral and CPC are in the correct terminals and that the switch operates 👍🏻. Thanks as always. Gaz
Allllllllllllahu Akbar!
Now I realise you mean ‘ nought point three’ and not ‘ nought point nought three’
SORRY
8.50....0.30 not 0.03
Ring circuits are the devil , am a spark of 25 + years , 4mm radial all day long 👌
Totally agree 👍
I have seen radials that are the Devil as well. A whole new radial with four or five sockets on it, *off the back of a socket,* with the socket terminal being the _star._ A few of them as well. The socket terminal worked loose, as they can and do, causing a black mess with a new socket needed. Sockets make poor junction boxes.
I only know how to change my phone 📱 lol
Why we persist with the ring in this country is beyond me. It’s an outdated and fundamentally flawed design which is illegal ( domestically ) in many European countries. Why ? because when there is a break it usually carries on working despite the fact it is now potentially dangerous as it has been de-rated by 50%. As a self employed electrician with 40 years experience who does countless E.I.C.R.’s I find one in three rings I test have an open circuit on one of the conductors and for that reason I always use 4mm Radials in new installations now. The domestic ‘ ring ‘ was brought in after the Second World War due to a shortage of copper. IMHO the ring should only be used in HV infrastructure to enable maintenance and continuity of supply.
pp0
You made a few mistakes with your readings.
100 %... the subtitles are correct and I apologised in the description. If you can forgive me the process should be helpful 👍. Thanks for watching and commenting
Only one small error in this version 🤦🏻♂️ it should help and has a better production quality 👍 kzhead.info/sun/iMmsiayOqox6YH0/bejne.html