@dhadumia 5 жыл бұрын
Couldn't thank you more for putting up this video. Large details of cable sizing are summed up beautifully in 15 minutes video. There could be many more topics to cover but for beginners like this much more than I could expect for. Thank you
@MarniLondon 5 жыл бұрын
Bcos of this great guy i managed to finish my college assignment thank you sir...
@robgreen7552 8 жыл бұрын
Chris videos are great! Even if you are fully qualified its always good to refresh the brain. keep up the good work 👍
@Cogibear 6 жыл бұрын
Thanks for the video......I studied this years ago and didnt understand it at all...........God knows how I passed my exams but going over it again here was very useful and made me realise I learned most things on the job :-)
@Andrew_Tate_Personal 5 жыл бұрын
Cogibear after studying how did you get into paid employment?, I’m currently studying level 2 electrical installation (C & G), I’m worried about how I’ll find a job?
@muralipk1964 6 жыл бұрын
Thank you for posting this video. A well explained calculation procedure! Very useful.
@Munchkin2000 3 жыл бұрын
If you had the kind of brain that takes in and retains stuff like that, there's no way you would be working on a site with tools in hand!
@LSF315 5 жыл бұрын
Very nicely explained. Just need to rewatch a few times for it to go in!
@topchannel1000 4 жыл бұрын
im learning more from your videos then my course thanks man
@mylesmacdonald7278 Жыл бұрын
This video is excellent, wished there was more people that could teach this way - Thank you
@chriskitcher 10 ай бұрын
Glad it was helpful!
@SeanyyBoy_ 9 ай бұрын
I used the Ci rating factor from the OSG accidentally. Easily done. It's not surrounded by insulation, just laying on top
@noahelekhtra9456 6 жыл бұрын
Hello This video helped me a lot to prepare for my exam. I got just one question for Cg factor (grouping factor ) for example when I got my circuit and I run it along with two other circuits the factor should be for 2 circuits or for 3 circuits ? I'm confused on that :/ I want to thank you for spending time to explain this sort of things to people. Really useful keep up good work.
@kathnava2413 4 жыл бұрын
I think Ib should be used instead of In when dealing with the Ca rating (i.e. It=Ib/Ca) to determine the appropriate cable size due to elevated ambient temp.
@chriskitcher 8 жыл бұрын
Hi, I would suggest table 7.1 of the on site guide may be of help to you. I have a video on you tube which guides you through the use of this table.
@wjelectricalsecurityltd 2 жыл бұрын
Great explanation. We use this to show our apprentice, although we are on 18th edition now the principles the same
@khalidrash5814 Жыл бұрын
Dear Sir, I would be very grateful if you could tell me which type of MCB is suitable for each of the following home appliances: - Split air conditioner. - Fridge. Electric stove. - the oven. - microwave. - dish washer. - Washing machine. Clothes dryer. Thank you very much sincerely Khalid
@chriskitcher Жыл бұрын
Type B for everything other than air conditioning type C for that would be best
@ef7480 8 ай бұрын
@@chriskitcher - or, do some basic electrical science study if you haven't already..
@Phillip22091980 7 жыл бұрын
great video i wish some would make a video on how you do a cable call for the AS/NZS3000 - AS/NZS3008 Australia standards
@carmicheal7 3 жыл бұрын
The end of the video misses the 80% rule and the 0.95% of cmin to be applied to the Tabulated Zs value in 7671 to allow for voltage fluctuations and a 50c rise in cable temp from the 7671 Tabulated Zs values when testing without load at about 20c in the field. The true max Zs permissable is actually only 1.10ohm.
@michaelstevens8328 3 жыл бұрын
Hi thanks for your great video! Just a quick question is the design current the rating of an appliance or is it the load after diversity. So a Hob for example if it is a 7kw rated Hob would the design current be the amount of amps after diveristy ie: first 10amps then 30% of the remainder? Many thanks.
@ef7480 2 жыл бұрын
Lol 12:13- "we don't really need to remember all that....." We just need to remember hundreds of 'tables' to make it easier.... Useful vid though. Now in 2023 (18th) 32A BS60898 is tabulated at 1.37 and corrected in OSG for 80% as 1.1 ohms
@krishath7085 4 жыл бұрын
Great video. Thank you Sir
@nazdalawi1195 3 жыл бұрын
Great video thanks
@chrissmith7259 3 жыл бұрын
Exam in a few hours si I thought I would give you a like and subscribe. Thanks
@CL3RIC89 6 жыл бұрын
i just want to add that the circuit protective device i assume is supposed to be B type 60898 not 6098
@WorldEngineersOnline 7 жыл бұрын
Hi chris, thanks for the video, I am new and learning. Can you recommend which books I can buy just specific to Cable Size Calculations and the relevant BS Standards to purchase, as lectured in your video
@apituraga9488 4 жыл бұрын
what the bloody hell??? I'm 40 years old and I just realised that 20% is the same as multiplying by 1.2!!!!
@paulpovey 6 жыл бұрын
Great video Chris, I'm doing 2396 at the mo and I have a quality teacher but always good to go over it for the bits I couldn't wrote down in time
@nemesisupgraded 6 жыл бұрын
Its a great video
@degreesdegrees-jr4eg 5 жыл бұрын
Is say 100 amp from 12 volt putting as much stress on a cable as 100 amp from say 230 volt ?
@shaunbeard593 6 жыл бұрын
Why in most houses as new build are all circuits in 2.5 twe. Even in loft. Surely some would have higher temperatures than others. But I have always seen 2.5 for sockets 1.5 for lighting 6mm for cookers and 8 for electric showers. Thanks for any help
@TheKie1978 6 жыл бұрын
Shaun Beard diversity
@technosync274 6 жыл бұрын
Well presented Chris. Thanks
@mikebizzleuk 8 жыл бұрын
Chris, Thanks very much for this video is was very helpful. i have a couple of points/questions. 1. i thought when you have applied the rating factors to your cable this value is then called Iz? You seem to call this It? 2. At 8:55 i think your formula for Zs should have the R1+R2 in brackets, so Zs=Ze+(R1+R2) 3. When calculating the Zs you adjusted the figure for operating temperature of the conductor. if i was going to use the max Zs value in the on site guide i presume i do not need to do this adjustment? Thanks again for posting such good videos
@chriskitcher 8 жыл бұрын
+mikebizzleuk Hi Mike, When you divide In by rating factors the result is It, It is the minimum current rating of a cable which is needed to carry the required current under the conditions indicated by the rating factors. Iz is the current which a cable could carry under the conditions indicated. If you select a cable and than multiply it by the rating factors it will show you the current which the cable could carry under the given conditions, this is known as Iz. points 2 and 3, you are correct. hope this helps, Kindest regards Chris
@chriskitcher 8 жыл бұрын
+mikebizzleuk Hi Mike, It shown in a calculation is the minimum current carrying capacity of a cable which would be suitable for the circuit being calculated. Iz however is the current which a particular cable could carry when multiplied by the rating factors affecting it. As an example a 2.5mm which is has an It of 27A with a rating factor for Ca of 0.94 and Cg of 0.85 would have a current rating of 27 x 0.94 x 0.85 = 21.53A under those conditions. It is the current rating given to the cable in the tables in appendix 4. The rest of your assumptions are correct.
@ef7480 2 жыл бұрын
Yes, good point re, R1+R2. 'Big' r1+'big' r2 are never separated. They become one in the calculation for Zs so yes it should read '(R1+R2)' to confirm line and cpc resistance as one figure. 'little r1' etc is separate from 'little r2' as in, continuity...
@mupparapunaresh990 7 жыл бұрын
Good explanation sir. Here I have a small doubt, please. As per standards, Up to 4kw have to take single phase i.e 230V, but here it is 7kw here we have to consider 3phase.( Is this correct or wrong, can u please explain)
@mupparapunaresh990 7 жыл бұрын
3 phase i.e 415V
@zippymo672 4 жыл бұрын
Very helpful in completing my design assignment for level 3 2365.
@ajmedia559 3 жыл бұрын
Fr bro helped me complete my design table
@papaluskask999 4 жыл бұрын
What is CPC? in impedance calculations to get R1 + R2 = 6.44? Was this from a table?
@chriskitcher 4 жыл бұрын
Rich Gallagher circuit protective conductor. Look at page 196 on site guide for r1 + r2 values
@crigeorge9549 6 жыл бұрын
good video Chris.
@user-fs3pb8dn6e 4 жыл бұрын
just to make a note in a new bs7671 18th edition, the voltage drop is in the table 4D4B and isn't on 4D5
@kalimbadeluna9120 7 жыл бұрын
I checked table 41.3 in BS 7671 for 32 A and type B circuit breaker , I found the value of ZS = 1.15 not 1.44 as mentioned in the video (1.44 is for type 1 circuit breaker not for type B)
@philharvey4945 7 жыл бұрын
Zs values have been adjusted since this video was recorded.
@Cogibear 6 жыл бұрын
You need to use the green book AMD No1: 2011
@crigeorge9549 6 жыл бұрын
now is 1.37
@Andrew_Tate_Personal 5 жыл бұрын
kalimba De luna this was prob the 17th amendment.
@melvintata 7 жыл бұрын
i think it should be bs en 60898
@ervantriwahyudi 6 жыл бұрын
How to calculate MV cable?
@IceyJunior 5 жыл бұрын
What if my load is not just a load, it’s 6x motors in parallel
@babakazizi3147 5 жыл бұрын
Magnificent
@DharmendraKumar-bi7yn 8 жыл бұрын
Is There any formula for cable size calculation for given load,without using any table reference
@mupparapunaresh990 7 жыл бұрын
Dharmendra Kumar No, u need to get cable current carrying capacity without that u can not find.
@hascodelavega3098 4 жыл бұрын
So we must put money by paying your book in order to fully understand your explanation...
@josh_maher7417 4 жыл бұрын
It not his book it’s city in guilds which u need anyway if you want to pass the course
@michaelbrownbill9654 7 жыл бұрын
excuse my ignorance but where is table L1 in the OSG?
@Cogibear 6 жыл бұрын
If your using the green book then its I1 and not L1
@davemorgan7695 6 жыл бұрын
page 190 in yellow copy
@abumohammadzarzour9371 6 жыл бұрын
New app. for cables calculation I designed it... Pls.enter link doun Regard..
@Thalasius 6 жыл бұрын
How do u work out size of CPC? @ 10:47
@MrBlackHalo1000 6 жыл бұрын
Twin and earth comes with CPC already calculated if you're using a 10mm2 live conductors then you'll have a 4mm2 CPC
@MrBlackHalo1000 6 жыл бұрын
If you wanna calculate the CPC you need to use the adiabatic equation
@Thalasius 6 жыл бұрын
See Table F4(i) On Site Guide
@kaynesteel4945 3 ай бұрын
thankyou so much you don’t understand how long i was trying to find that for
@muneebshahbaz3560 6 жыл бұрын
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