SEE ALL - To view a list of all our LearnElectrics videos, click on the link below. There are many videos on many electrical topics including Installation, Part P, 18th Edition, Testing, Certification, Lighting, Sockets, Ring Circuits and much more. kzbin.info/door/YaJQnpO4XAp0yCgqzMkmfA
@grantrodgers28293 жыл бұрын
learning the alternative calculation for unknown lengths / wire gauge has helped immensely. Thank you
@learnelectrics44023 жыл бұрын
Yes Grant, that's a good one. It came in very useful on periodic inspections over the years. Not a lot of folks know about it. Glad you're enjoying the videos. The video link below was the first video I published, this has an interesting "Trick Number" in it that you might like. Thanks for watching, appreciated. Dave. 35 is the Magic Number kzbin.info/www/bejne/i4OldWeiobGIbLs
@maal4913 жыл бұрын
This video is so helpful, better then my actual book itself , thanks 🙏
@learnelectrics44023 жыл бұрын
Excellent, thanks for the very positive feedback and so glad we can help. Lots more videos to come. Bux
@sophiaenright15833 жыл бұрын
this is so helpful for my electrical engineering exam, thank you sir! very well explained :)
@learnelectrics44023 жыл бұрын
So glad we can help Sophia. Lots more videos on our channel and lots more to come. Good luck with the exam. Dave.
@musangobi20793 жыл бұрын
Good explanation, now I will ever get confused about voltage drop
@learnelectrics44023 жыл бұрын
Glad we could help. Practice the formulas and you will have a skill for life. Bux.
@seandempsey93963 жыл бұрын
Fabulous I hated learning this when I was at college, but it is so important that we do learn it, fabulous video as always. Thank you
@learnelectrics44023 жыл бұрын
Thanks for the good comments Sean. You can also read this on our website at www.LearnElectrics.com We are in the process of uploading written articles to the website for all the previous videos. It will take time but we will get there. Thanks again Sean Bux
@IftikharAhmed-lk5yk2 жыл бұрын
Excellent Videos, thank you very much. ONE QUERY PLEASE: voltage drop for single strand wire is 44mv per 1mm"csa per 1metre length, (my understanding) and for 2.5mm" wire voltage drop is 44/2.5 = 17.6mv per metre In this example we have 2.5mm" T&E 25 metres long ie 25 metres live wire and 25 metres neutral wire. So when calculating voltage drop for 25 metre long cable, the total length of current carrying wire is 25 m live and 25 m neutral = 50 meters. Voltage drop (milli volts) = (44 mv X 20 amps X 50m length) / 2.5 = 17600 mv = 17.6 Volts. This is what I Understand, please look into this as there is lot of confusion. Its same for cable resistance. 19 m ohms / 1mm" csa / 1m length for one wire only.
@learnelectrics44022 жыл бұрын
I'm quoting from Guidance Note 3 and the Wiring Regulations which rounds the numbers up or down to whole numbers. On an average run length of cable it will only make a tiny difference. Thanks for watching. Dave.
@IftikharAhmed-lk5yk2 жыл бұрын
@@learnelectrics4402 Thank you for for quick reply. my point was there are 2 wires (live and neutral) each 25 metre long, so when calculating voltage drop total length of wire will be 25 + 25 ie 50 meters. So when calculating voltage drop in one 25 metre long strand = (18 X 20 X 25 ) / 1000 = 9 VOLTS and in 2 strand (live + neutral) voltage drop will be double, ie 18 volts. Table 2 / 4d1 (single) states voltage drop is 18 mV for 2.5mm" csa per metre.
@sanbucaone3 жыл бұрын
Thank you, very well explained. Found it interesting to have alternative methods of obtaining vd. Keep up the excellent videos.
@learnelectrics44023 жыл бұрын
Glad you liked the video, your feedback is appreciated. Most colleges only teach you the minimum. We like to teach you what you need to know to be good at your job. Practice a few made up circuits and you will have a skill for life. Bux.
@u.a31853 жыл бұрын
Best teaching method I ever seen .thank you sir !
@learnelectrics44023 жыл бұрын
Wow. Thanks for the great feedback Usman. Really appreciated and thanks for watching.
@user-sx4ch2lz6r Жыл бұрын
Great video! Finally understand this. Now off to search your channel for a video on correction factors.
@learnelectrics4402 Жыл бұрын
Glad it was helpful Gareth. The correction factor video has just been put on the list to be done, thanks for the nudge. But there are still lots for you to look at, thanks for the support, Dave.
@antoniogalluccio42132 жыл бұрын
The best video on KZbin regarding the topic and more complete of the others. Thanks for sharing this info with everyone, it is really helping out towards the 203 mock exam level 2. 11.5 volts permitted comes out of 5% of 230 volts right?
@learnelectrics44022 жыл бұрын
Absolutely right Antonio. You've got it. Thanks for watching, lots more to come. Dave.
@donalfinn42053 жыл бұрын
Much better than any book!👍☘️
@learnelectrics44023 жыл бұрын
Well thank you very much Donal. Your comment means so much. Really appreciated. Dave.
@tilidie5272 Жыл бұрын
youve helped me so much this channel is priceless to me!
@learnelectrics4402 Жыл бұрын
Excellent, if it is helping it is doing its job. Thanks for watching, spread the word. Dave.
@joelgobeh73432 жыл бұрын
Superb!!! You just make serious topics look easy.🙌🏾🙌🏾👏👏
@learnelectrics44022 жыл бұрын
Thank you so much Joel. What fantastic feedback. You've made my day. Dave.
@alextaramsari3 жыл бұрын
Another well explained video!! THANK YOU!!!
@learnelectrics44023 жыл бұрын
So happy you appreciate it. Your comments really make the effort worthwhile. Thanks. Bux.
@colinblanchard28286 ай бұрын
This has been very helpful, thanks
@learnelectrics44026 ай бұрын
Glad to hear it, thank you.
@mrpoo76512 жыл бұрын
This is very well explained. Helped me a lot. Thank-you so much sir
@learnelectrics44022 жыл бұрын
You are most welcome, thanks for watching. Dave.
@adaliqbal69729 ай бұрын
I have been following your Videos and they have been very helpful to me as i can often have learning difficulties in classroom environments. They have been more helpful than ever before as my fulltime work is conflicting with the college classes at the moment and I am trying to play catch-up with Revision. 1st time leaving a comment and I felt the need to do so as the videos have been fast and informative and very understandable. I am a level 3 electrical installations student. Your work is a massive help with the theoretical aspects of the course. Appreciate the references to the onsite guide and also the Worked examples.
@learnelectrics44029 ай бұрын
That's great news and so happy they are helping. Keep watching, lots more to come and do spread the word about the channel at college, there might be others struggling too. Dave.
@adaliqbal69729 ай бұрын
@@learnelectrics4402 Good Idea will do that definitely.
@peterhorsell51863 жыл бұрын
Great video, very helpful thank you. 1 question though - if looking to extend an existing circuit, do I need add the total maximum of all consumers on the circuit and calculate length of cable, to be able to work the figures out and check if the proposed additions would comply? Thanks
@learnelectrics44023 жыл бұрын
Yes, any extension to the circuit will increase the resistance in the circuit and increase the volts drop. Having said that, if the Vd was just 5 volts, say, for a 15 metre socket circuit and you were extending by perhaps only 3 metres, it is clear that the extra 3 metres will not take you over the 11.5 volt limit. Hope this helps. Bux.
@robertwainwright54415 ай бұрын
Another great video 👍
@learnelectrics44024 ай бұрын
Glad you enjoyed it. Thank you.
@AndrewCook72 жыл бұрын
Great Dave thanks. Why do we not use 50 mtrs for a 25mtr length. We have phase and neutral, 2 length of cable. Always wondered why the length is from the source to the appliance and not the return as well
@learnelectrics4402 Жыл бұрын
The voltage drop calculations that the boffins give us have included the phase and neutral paths. Hope this helps. Dave.
@gino2465 Жыл бұрын
Good morning quick question on a previous video you had some handy formulas my question is the formula was for 230 v what is differant if it's 3 phase 400v
@learnelectrics4402 Жыл бұрын
Thanks Gino, someone else asked about 3 phase voltage drop so it must be time to do a video. Thanks for asking, its now on the list. Dave.
@dennisfowler78733 жыл бұрын
Another great video .... been waiting for this for a while now...one question.... can both formulas use the 1.2 multiplying factor or is it just for the ( R1 + Rn) formula
@learnelectrics44023 жыл бұрын
Thanks Dennis. Only the R1+Rn calculation uses 1.2. The (mV/A/M) number in the standard formula has already allowed for temperature adjustment. Hope this helps. Bux.
@ranjan14362 жыл бұрын
very nice, you make things look so easy? thanks very much.
@learnelectrics44022 жыл бұрын
So glad we could help Swapan. Thanks for watching. Dave.
@michaelcostello69913 жыл бұрын
The first method used the length of cable and the second method used double this value ie live and neutral lengths added. Do we need to understand why is this or is it something we should accept. Thank you for great video
@learnelectrics44023 жыл бұрын
Michael, method 1 is when you know the cable sizes, lengths and (mV/A/m). Method two is when you have two ends sticking out of the wall, no real idea of length, size debatable and no chance on (mV/A/m). All you know is the load of the attached equipment. Typical when inspecting and testing some properties or factories. Method 1 you will need for 18th exam. Method 2 will give you the skill to work volts drop out on site when everybody else says it is impossible. Learn both, look good. Hope this helps. Dave.
@azizullahkhan7888 Жыл бұрын
Thanks for uploading informative clips
@learnelectrics4402 Жыл бұрын
It's my pleasure, glad you enjoy them. Lots more to come.
@gregmcallister4862 Жыл бұрын
Very informative, and great content
@learnelectrics4402 Жыл бұрын
Thanks for watching Greg.
@Gandalf4137 Жыл бұрын
How would the equation change if we used an aluminum conductor instead? I believe its mV/a/m rating would be different, no? Thank you.
@learnelectrics4402 Жыл бұрын
Yes, the data would change. Every material and mix of alloys has its own data table. For Aluminium cables have a look on page 479 in the brown Regs book. Thanks for the support. Dave.
@mohammadmoradi398321 күн бұрын
Thanks alot very useful
@learnelectrics440220 күн бұрын
Nice of you to say so, thank you.
@sanbucaone2 жыл бұрын
Evening just revisiting voltage drop.😁 with regards to voltage drop when the load is unknown ie a summer house with three double sockets. And it’s unknown what client would plug in. Would we use the Breaker size at the board as Ib? I guess my question is if ib unknown do we use the breaker size to carry out the formula. Many thanks.
@learnelectrics44022 жыл бұрын
Absolutely. Yes, us the rating of the breaker as your Ib. Thanks for watching. Dave.
@gbelectricks3 жыл бұрын
Great video. On the last formula could you explain the 44 figure on the top row of the equation? Where does this come from and why is it always 44? Thanks 👍
@learnelectrics44023 жыл бұрын
44 is the reference figure that makes the equation work, it is the value for 1mm. Try it with the same values we have just used in the first example. 20 amps x 25m x 44 divided by (11.5 volts x 1000) gives 1.91mm minimum cable size and in the example we have chosen we have selected 2.5mm. Hope this helps. Bux.
@tww57193 жыл бұрын
Where does the formula of how the cable is run,and the thermal conditions come in towards the final volt drop eguation xx
@learnelectrics44023 жыл бұрын
You should calculate the cable installation conditions and thermal conditions first to determine a minimum size and then the voltage drop to check that the size selected is ok. Hope this helps, it can be tricky sometimes deciding which is the best order. Dave.
@tww57193 жыл бұрын
@@learnelectrics4402 yes thanks,must admit a lot of electricians take things for granted without working out the volt drop,when I did the 17th update the lecturer was hot with volt drop,he gave us a sample for a 10kw shower in a house ,no great run and nothing special,it come out as the minimum of 16mm,everyone was shocked so to speak,I told him the manufactures had better make bigger switches to take a 16mm,I mainly do industrial work which is a different kettle of fish and working out voltage drop is a must 👍
@patrickjacobsen78052 жыл бұрын
So good.
@learnelectrics44022 жыл бұрын
Great feedback Patrick. Thank you. Dave.
@krazylad843 жыл бұрын
excellent stuff, thanks !
@learnelectrics44023 жыл бұрын
Thank you for the positive comment, appreciated.
@mprime11542 жыл бұрын
Thank you Sir
@learnelectrics44022 жыл бұрын
Most welcome, thank you for watching. Dave.
@drpantastic19692 жыл бұрын
Question does how a cable is installed affect the calculation say for cable sizing for example
@learnelectrics44022 жыл бұрын
Yes it does, we will be putting out an updated video on this soon. Dave.
@Ramesh-nc7xw11 ай бұрын
If i am calculating voltage drop for a lighting circuit do i use the measured length of the cable from the distribution board to the furthest light fitting or do i need to multiply that value by 2 seeing as the current has to travel back to the distribution board.
@learnelectrics440211 ай бұрын
take a look at this latest video we've made on voltage drop, it will give you more information. But to answer your question, only measure the distance one way, from the CU to the point of use, NOT there and back. dave. kzbin.info/www/bejne/pIe9lnx8mqqqopI
@DasTwigster Жыл бұрын
brillant thanks
@learnelectrics4402 Жыл бұрын
Glad it was useful, thanks for watching.
@icetin75683 жыл бұрын
GREAT VIDEOES AGAIN MANY THANKS . Can you do more videos about inspection AND TESTING or EICR , SEQUENCE OF TEST . I CANT WAIT . ,MANY THANKS
@learnelectrics44023 жыл бұрын
Thanks for the great comments. Testing, certificates etc. are on the list and we will be doing videos on these very soon. Thanks for your patience and suggestions. Dave.
@maal4913 жыл бұрын
@@learnelectrics4402 I am interested on that too, can't wait
@learnelectrics44023 жыл бұрын
Thanks, we will do this video very soon, meanwhile, enjoy the others. Glad you are finding them useful. Bux.
@maysasaeed79642 ай бұрын
ممتاز
@learnelectrics4402Ай бұрын
Thanks for watching. Dave.
@gino2465 Жыл бұрын
Hi I have tried this using the tables in osg to compare, it's very close to 2.5 wire but say not with 16mm cable using the majic 1.2 factor
@learnelectrics4402 Жыл бұрын
The OSG rounds up/down the figures so there will always be tiny differences.
@echenduconfidence49983 жыл бұрын
Thanks sir for the great video. Pls what is the name of the reference book you use in this video.
@learnelectrics44023 жыл бұрын
Thanks for the comments. All the information is in the Wiring Regulations and the On-site Guide. BUT - There is more information in the video than in the books, I have added to what you will find in the books. Dave.
@user-fo9vl2pj7o Жыл бұрын
thanks
@learnelectrics4402 Жыл бұрын
Your welcome, thanks for watching.
@mohammedborhan96772 ай бұрын
Hi, can you please send me the formula for voltage drop for socket three phase For single phase is 11,5 What is the formula for three phase Thank you
@learnelectrics4402Ай бұрын
The tables, with all the different numbers for 3 phase are in Appendix 4 of the Brown Wiring Regs book. Thanks for watching.
@frog.n.toast29382 жыл бұрын
7671 2sd amendment videos will be welcome !great job
@learnelectrics44022 жыл бұрын
We're already up to video 7 on 2nd amendment. Thanks. Dave.
@alig78003 жыл бұрын
THANK YOU
@learnelectrics44023 жыл бұрын
Glad you enjoyed them. Thanks. Dave.
@kdiddy47143 жыл бұрын
Thank you
@learnelectrics44023 жыл бұрын
You are very welcome. Glad you found it useful. Bux.
@hanzlaabbas24882 жыл бұрын
Length is 25m is this only way or complete length of the cicruit from phase to neutral
@learnelectrics44022 жыл бұрын
The length from the CU to the point of use.
@learnelectrics44022 жыл бұрын
as below
@natarmstrong89313 жыл бұрын
Struggling to find the voltage drop equation for a ring main circuit.....any help would be appreciated.
@learnelectrics44023 жыл бұрын
Good one Nat, there are lots of variations for working this out. Good news, Thursdays video is about Ring Circuit voltage drop. Hope you enjoy it. Dave.
@pah9844 Жыл бұрын
So I know I’m doing this right, can somebody help. If I look at the final formula question, min size of cable to not exceed VD. My own numbers made up below; 1b 3kw = 13amp L 44 vd 11.5. 13a x 44L 11.5vd x 1000 Do I have this right?
@learnelectrics4402 Жыл бұрын
No, you've missed part of the formula out Paul. You have not included 44 for the mV/A/m standard value. the top row should be 13 x 44 x 44 and the bottom row 11.5 x 1000 This will give a cable size of 2.1mm minimum. You should choose 2.5mm cable. Hope this helps. Dave.
@pah9844 Жыл бұрын
Just realised what I have done…. Misread the formula and put 44 as L.
@mikeadler434 Жыл бұрын
👍👍👍
@learnelectrics4402 Жыл бұрын
Three thumbs, appreciated. Thanks for watching.
@IceyJunior Жыл бұрын
mV/ A/ m isn't it the same as m\Ohm / m?
@learnelectrics4402 Жыл бұрын
It is called mV/A/m in the regs book. Other industries might use a different abbreviation. Thanks for watching.
@rohulamin53533 жыл бұрын
Can this work for ring final
@learnelectrics44023 жыл бұрын
Yes, have a look at our video Cable length calculations and R1+R2 on this link kzbin.info/www/bejne/h6LCaoCEfZ2Lrrc It covers ring and radial circuits. Thanks for watching
@sorbunsong69343 жыл бұрын
sir , how can i download bs code for applying in electrical?
@learnelectrics44023 жыл бұрын
If you need the British Standards documents search Google for the BS number.
@sorbunsong69343 жыл бұрын
@@learnelectrics4402 but bs code is not for free sir
@learnelectrics44023 жыл бұрын
That's correct. All BS documents have to be paid for. There is nothing we can do about that, if it is needed you will need to buy it from BSI. Hope this helps.
@mohammedborhan96773 жыл бұрын
Hi teacher could you please give us example for cable calculation for three phase for one heater or cooker and second example for three phase also but we need to install 3 ovens every oven is 5.8kw alle these ovens in same cable and one circuit breaker. Thank you
@learnelectrics44023 жыл бұрын
Mohammed, we cannot give specific sizes for what you want as we haven't seen the installation and we do not know the installation conditions. Look at our video Breaker and Cable Sizes for Electrical Circuits kzbin.info/www/bejne/aZCnZ2hjaJerppo Thanks for watching
@mohammedborhan96773 жыл бұрын
@@learnelectrics4402 thank you for your response and if you can just one example for three phase cable calculation Thank you
@learnelectrics44023 жыл бұрын
We will be doing a video on three phase in the near future.
@mohammedborhan96773 жыл бұрын
@@learnelectrics4402 what is the reason we have higher measured earth loop impedance ? And what is consequence for that? Thank u
@learnelectrics44023 жыл бұрын
Usually poor circuit design in the first place or additions to circuits without recalculating. The consequences of high Zs could be that the breaker does not protect the customer properly and they die. Look at our video Zs too high kzbin.info/www/bejne/nIbPdHeeoch3nJY
@pah9844 Жыл бұрын
Could i pick your brain just the once more. My own cooker. Ib 4kw -4000w L 1m cable. mV/A/m is 6mm cable 7.3 mV/A/m (table 4d5) 7.3 x 17 x 1 ~~~~~~~~ 1000 0.12 amp drop Thanks.
@learnelectrics4402 Жыл бұрын
Yep, that's almost correct Paul, it will be 0.12 VOLTS not amps - but is it really 1 metre from the consumer unit? If it was 10 metres from the Cu your Vd would be 1.2 volts Thanks for watching, lots more to learn. Dave.
@pah9844 Жыл бұрын
@@learnelectrics4402 i was just making up a low number to see the difference.