Cable size Circuit breaker amp size How to calculate What cable

[@GentlemanH]

Thanks for a clearly explained video. Just a point to remember when referring to a six millimetre cable it refers to the cross sectional area of the copper and not the diameter of the copper wire. Back when I started in home renovation, I would measure the copper wire with a vernier and then wonder why 6 mm was not the diameter ? Of course not - 6 mm refers to the area - it should be written 6 mm2.

[@danielteyehuago1633]

I agree with you. You did well for going extra miles

[@adamgallin9130]

Thanks for the comment, makes sense ;)

[@jeremykemp3782]

You are wrong sorry sir, for domestic houses the voltage drop is 6 % for lighting and 8% everything else. So thats 8% of 230v which is 18.4 volts you are allowed in total. mv/amp/mtr

[@CarlosArruda77]

No mention of diversity for the cooker. Nevertheless very effective and easy to follow video. Well done buddy.

[@Vision267]

What is the diversity of the cooker

[@nathimngadi764]

Thanks so much for helping me from south Africa clear and simple👍🏾

[@andilemngadi1315]

madlokovu

[@tonyomalley901]

Dreadful video, very misleading and potentially dangerous

[@markgilder9990]

Your calculations for the cooker are incorrect. You need to take into account Diversity. From the On site guide or IET BS7671 2018 Amd3. 10kw cooker 44 amps. Take the first 10 amps then 30% of the remainder plus 5amps if a socket is run from the cooker isolator. 10A + 30% of 34 =10.2A + 5A for the socket if applicable. Your demand is 10+10.2+5 =25.2A.

[@ef7480]

Smarty pants ...

[@gassafe9810]

You forgot to take into consideration diversity, so take the first 10A and 30% of the remainder = 10 + 11.33 = 22.4 A approx , so theoretically 2.5mm would suffice if on a type B circuit breaker, 4mm to be safe. ( 6mm cable comes from the old days on semi enclosed fuses - where the correction factor pushed up the requirement for a larger cable)

[@satish8299]

The what? The diversity ? you mean tollerance ? I dont understand that 11.33 A

[@septin2008]

You have to assume that not all the burners and oven etc in the cooker will be on at the same time and draw full current. So we diversity meaning an average current that would be use so 10000/230 = 47amps,take 10amps out will leave 37.then you have to take 30% of 37 which is around 10 or 11 and add back the 10amps that you took earlier and will give you around 21amps. In this way you can use 32amps mcb and a lower siZe cable.

[@jamalkhan1974]

@@septin2008 I think Diversity is ONLY used to calculate the overall current demand of current in the house to see if the demand goes over 60 or 100 Amps etc. If you you diversity for calculating MCB and cable size, you would end up tripping MCB whenever you use the full load (xmas cooking etc) or if you had a bigger MCB but a small cable, then cable will burnt down when full load is used......

[@badfairy9554]

@@septin2008 I was told to get a 4mm.

[@chrisroberts8745]

this video is brilliant / really easy to follow for anyone. thank you!

[@kevindodd4004]

Hi you didn't allow for the length of the cable the correct method for calculating cable sizes is by using the adiabatic equation not a table in the building regs book, you have wannabe sparkys watching this and could get the wrong idea sorry to be negative but it is critical to demonstrate cable sizing correctly

[@henny1387]

Can you please explain how to do it correctly

[@chrischaralambous286]

Excellent explanation. Thank you for this educational video.👍👌

[@bubazomo1993]

Though I am not an electrician by profession but I have been in the power industry for 5 years now. It is an excellent video for learners.

[@DavidBromley123]

A very simplistic look at the cooker circuit, you need to take diversity into account as the load is thermostatically controlled and therefore wouldnt pull the full load all the time.

[@eugeneoreilly9356]

You may not pull full load all the time.Pulling it for a split second will trip the breaker.

[@232beachroad]

I am an electrician ,and on cookers you should allow for diversity , this is an allowance in the electrical ie regs, that means you would never have the cooker on full load ,talking the full 10kw while cooking ,( every oven and ring on full power) this means a 32A CB would be OK with 4mm cable for a short run and 6mm for a long run of cable.

[@user-yh4kl3hx2o]

No bro 6square only

[@ayvanmusa8515]

I did not get wy he counted the cooker fuse as 45A but in the schedule he put 32A?

[@arcsw]

Sir, can you make a video on calculation of electric load for a colony and how to select transformer for that colony?

[@johnstancliff7328]

the same applies in the North America market. the only thing that different is the sizing, Europe used the Millimeter system, and we use the AWG system, American Wire Gauge. here the rule is 14 gauge= 15 amps, 12 gauge=20 amps and 10 gauge= 30 amps.

[@TonyofCornwall]

One of the best and easily understood tutorials I've seen. Absolutely excellent 👏

[@ErenPlaysNsh1t]

Great video. Taught me more in 15 minutes than my place of learning did In 3 hrs.

[@ateleskier7066]

Top marks! Excellent video - very clear. Will check out your others now. 👍

[@steevek]

at 1:15 talk about cable size 6mm, 2.5mm and 1.5mm. Iit should be read as 6mm square, 2.5mm square and 1.5mm square instead. Many thanks for this video!

[@hamzagarmaje7898]

Looking for work, I couldn't find a better way to talk to you. I work in the field of electricity for homes

[@macspud28]

Interesting. I hadn't realised just how much running cables through insulated walls makes to the amperage rating of the cable. It's definitely, something to keep in mind when adding insulation to existing walls, ceilings etc.

[@telosfd]

Cooker never works at full power. So 25 Amps fuse it's the proper value.

[@sayyidtawaqal1754]

Thank you brother can you please help me with this knowledge I'm said from Zanziber in Tanzania

[@gazmendnamani1457]

One thing to remember regarding cookers... If it is a three phase connection than that 44 is divided by 3, which means you can connect each of the phases separately and the cable size does not have to be bigger than 2.5mm and size of three breakers collectively has to be 20 Amps each (44x1.25=55÷3=18.33)

[@badfairy9554]

After waiting two weeks for a new cooker from a place that has the same name as a god, I paid for it to be put in. A bit more than £100. They said they could not do it. That I can only have a cooker thats 20 amp. I did not watch them try. My lights went off and on many times. So I went to see what the hell was going on. My fuse box says 32A . I have to wait 30 days to get my money back.

[@alunroberts1439]

So we're is your volt drop calculation for the load also did you consider diversity calculation for the cooker also socket on the switch as most still have socket on the cooker outlet.

[@danielteyehuago1633]

Please can I get link to download the book. Thanks

[@PRANX1000]

Being a competent and good Electrician takes years to master , from domestic installations to industrial installations , to learn this trade you need to start at grass roots doing the dirty gritty work .

[@nortaviaatpl8687]

Mate can you do the video of electrical switching automatically from grid to generator .... and how to connect the wiring from panel solar to grid please

[@captainselly9419]

Excellent video, thanks for sharing. I have a question if you don’t mind please , cooker 10Kw is it per hour ?

[@grecuby]

The 45A MCB would trigger between 135A-225A if it's a B curve and between 225A-450A if it's a C curve. Why are you using a protection so big? Just asking, I'm probably missing something.

[@saraweshwaranbashkaran4499]

Simple. Amp of electric appliance

[@jthompson8234]

Shouldn't the wire burn out just incase the circuit breaker is bad?

[@peterfitzpatrick7032]

My understanding (I'm not an electrician) is that the circuit breaker limit is set lower than the cable carrying capacity to prevent overloading of the cable... BUT the fuse in the appliance plug is to protect the appliance itself... The cable , say a 2.5 T & E radial carrying 10 socket outlets would have a 16 amp breaker (for a cable in conduit in an insulated wall) and the individual appliances would have lower rated fuses, say a 3 amp for a bedside lamp, in their associated plugs... 🤔 😎👍☘🍺

[@SamuelArthurBapiego]

It should be mm² since it refers to the cable's c.s.a.

[@ez8294]

Helpful video. I'm level 2 electrical installation student . Can't wait to become an electrican .

[@trimi68]

this is valid only if you use a single phase feed

[@diazsel1157]

You have explain the calculation to obtain circuit breaker amp size and from there, select the cable size based on the table. But, I am curious about the calculation to obtain wire size. Why using 1.5 cable for ac for for example can cause it overheat. What is the maximum by calculation for current to pass through wire certain size.

[@ajithomas8342]

I need to be calculation test books .any advice .Thanks brother 🌹

[@sckvkrc4732]

No good example was chosen. The simultaneity coefficient was not taken into account. Also, a three-phase power supply (3 x 400VAC) is usually used. Then the current is about 15A and the cable is 5x1,5mm2. MCB, is for 16A.

[@danith72]

The lighting in my house has 1mm2 cable with 6A. I want to install a lamp with a bulb hanging out from the ceiling. Can I use 0.75mm2 cable instead?

[@mahdidebbih949]

The size of the cable is in squared millimeters

[@jeetenderkakkar7570]

Size

[@aliherati5069]

if the shower has 9.6 kw then the design current will be 9600/230=41.7 amps how can we use 40amps circuit breaker for that which is lower ?

[@jjperera3389]

Just remember there is diversity in cookers 10amps x30% of the power output of the oven and + 5amps if it has a socket with the switch, 6mm is fine for reference method 101

[@oohtob6685]

I use 4mm cable and 20mcb for my HIFI.

[@ELLIADSUMAILI-nb6sk]

Thank you for your guidance. And am asking for a book you have highlighted. I have tried to download but I have failed. Help me by sending it please

[@jacksonzheng4288]

So， for non electrician people, how do I know if it is 6mm?or4mm??? Please talk about this instead only introducing their difference on that table

[@weldmachine]

A great way for people to understand how an Electrical cable can heat up so easily. Is to use a high power appliance then feel the cable with their hand, after using the appliance. A great example would be something like a Vacuum or Electric room Heater. It surprising how much even these simple items can heat an Electrical cable. And these cables are outside the wall where they can radiate the heat away.

[@minayowitz3268]

The video should come with a warning that in the UK any alteration to cable circuits needs to be done by a competent person (qualified electrician). It's not a DIY job.

[@PRANX1000]

I was going to advise something like that . I am a sparks and this isnt good , someone will go and try their luck and could kill somebody or burn someones house down .

[@piotrf7648]

@@PRANX1000 what do you mean pal,what is not good?

[@PRANX1000]

@@piotrf7648 I already said what i said , i been in this game for years and it is my opinion , it takes years to become competent and know what your doing , not just by watching a video .

[@jackself4774]

What size SWA cable would I need to run power from house to shed about 8 meters from house to a mini board with 2 mcbs one for a light and one for 2 double sockets on a ring; does it need to be 6mm SWA or 4mm SWA

[@eugeneoreilly9356]

Underrated cables are a fire hazard.Coiled wire offers a high impedance (resistance)to AC.Never run AC thru coiled wire.

[@edward_grabczewski]

I like this simple approach to calculating the design. I can't see a problem with using cable that's over-rated at is has less resistance and can cope with future changes to circuit usage. Diversity is an optional consideration if you don't want to spend too much on cabling etc. but it takes no account of future usage, so having larger cables is fine if you want to pay for it.

[@satish8299]

What do you mean take the "diversity" into account? Is that the tollerance of the cable? O you mean 1 usage of voltage between L1 and L2 ? He choose 230 Volt and that is between L1 and Neutral, so there is no square 3

[@eugeneoreilly9356]

Yes,it eventually boils down to cost.People often add extra loads to circuits without considering the cable power rating.

[@jxwirecable]

Interesting video, learn it. this series cable, we can produce it. we are factory focus on cable manufacturing.

[@boualemstihi5349]

Thank you so much for this video. Am just asking what about 1.5kw here which cable I can use it please.

[@ayvanmusa8515]

you got 45A for the fuse of the cooker.. why did you put 32A for a fuse in the last schedule?

[@kaleemyousafzai827]

there are two types cable comes in it one is aluminum and one is cupper plz make one video for aluminum cable how much current carry by aluminum

[@davidmorrill2943]

When the guage of wire is measured , does the diameter measurement include the the Insularor and core or just the core. Thank you ?

[@sharafsiyad4500]

The first question... If its 10kw no body will select single phse...

[@PinoyElectrician-jr8bu]

Hi thank you for your videos. I am inspired. I am here in Uk for 3months and ongoing taking of NVQ. I'm electrician back home ( Philippines ) 7 years of experienced at the Philippines and 2 year's at Saudi Arabia. Sadly I can't apply for electrian here in UK without NVQ or gold card. 😅😅☺️

[@Anthony-np9cn]

Please write your fgures correctly, This is how to write the number 7 and not how you do it, Ok

[@daz3660]

What size cable would I need for a double socket outside for a pond etc 130 feet from the consumer unit please

[@patterdalezipsuzilil]

Download pages of the electic regulations it is all in there

[@aliherati5069]

in this example for loading 10 kw cooker::: the rating of fuse according on table 41.3 onsite guide bs7176 must be equal or bigger than the design current which is 50 amps not 45 amps which is not in the table then the cable size will be according on table 4D2A 10mm not allowed 6mm because need to choose 65 not 47 amps. need to consider some other factors like ambient temperature , voltage drop

[@farkhandabintmohammadalabb7491]

Clip direct means? When your wire is directly attached i the socket of 47 mpr?

[@muhammadwalhakim8596]

Wrong calculation. If you wanna find Ampere(in case AC power, and only know Whatt), you have to use formula : Watt/(Volt x Power Factor) . If you have VA, you can use your formula : VA/Volt

[@azimkure9323]

Thanks for the information cable

[@horatiofluffytop]

A really well presented and informative video, thank you.

[@khalidrash5814]

Hello sir, Should the outdoor service switch be greater or smaller than the main breaker in the consumer unit? I'll be so grateful if you would send me back. Thank you, Khalid

[@petersack5074]

Good. the building code, is the bare minimum. Anything, i do with wires, power, always use a gauge 2 numbers larger. 14 should be 12, in a house. 8 should be even 7 or 6......etc. 16 is TOO SMALL FOR XTENSION CORDS, try not to use these cheap POSs'. oldtech.,

[@petersack5074]

the 'plastic' female ends, overheat on a large draw, FIRE HAZARD. ...

[@jankelbich4605]

OK, it's nice. But 45 A for cooker is too much. Better idea is connect cooker as three-phase load (with neutral conductor), and then current will be smaller, aprox. 15 A.

[@tombird3032]

What I don't get is I have 10 lights at 7.5w each right so all together 75w I divide that with 230v getting something stupid like 0.3a??? 😂 So what should I use a 1 amp breaker lol

[@GlynWilliams1950]

WRONG. Size cable for worst case installation. 1.5mm = 10 amps. Dont have different cable sizes connected together if the cable is installed in different situations.

[@frankbumstead3838]

Well done, best technically designed and factual video on this subject.

[@carlmarquardt994]

How do you decide whether to use s CB or rcbo ect?? Are fuses banned if are are running s new circuit on an existing fuse board which has Fuses? Also for guys doing vthe testing and inspection periodically..if an old board with fuses Which passes ir Tests ect must it be changed??

[@koladeadebayo5179]

Good Morning! Nice work! Three things here, 1. You didn't consider power factor (cos theta) 2. What is the phase (single or 3-phase)? 3. Please,what is the name of the handbook and how & where can I get an electronic copy?

[@khanlahlah1487]

its called On-Site GUIDE ,make sure buy the 18th Edition and you can find the all info and installation method about wiring.www.amazon.co.uk/Site-Guide-7671-Electrical-Regulations/dp/1785614428/ref=sr_1_1?ie=UTF8&qid=1543285293&sr=8-1&keywords=18th+edition+on+site+guide

[@rebbenius5630]

6mm? Really? You did measured the whole insulation not the gauge of the core wire.

[@spencerwilton5831]

It's the cross sectional area of each conductor. Millimetres squared. Not the diameter or width. Electricians just abbreviate to 6mil rather than saying the whole thing.

[@ssarraf6855]

Thank you for the presentation. Would you please add the equivalent “gauge” size of the cable as it is used in the US THANKS

[@kangtheconqueror]

Hiya. I'm enjoying your videos Buddy. Just thought I'd mention it, as you did choose to use a cooker as your example. Don't forget to apply diversity as it is highly unlikely to ever reach its maximum demand due to the thermostats in the cooker rings. In your example (44 A) it would be the first ten amps (10 A) then 30% of the remaining amps (approx. 11 A) PLUS 5 A if there's a socket outlet on the cooker isolator. So, your 44 A has gone down to 26 A. The next MCB up from that is a 32 A. I'd still use 6mm cable though.

[@cater4anytink45]

Kevin McNicholas I've always been told to use 10mm by my boss..I suppose this would save money if working for yourself.. I've recently sat the 2391-52 exam,no one could give me a exact way too work out maximum demand/ diversity nt even in bs7671 book

[@kangtheconqueror]

cater4anytink Yeah, I know what you mean. I suppose it would be useful to if the oven was ever upgraded again. It's a trade off though, isn't it? If customer wants to pay for cable that is far and away able to deal with the demand, fair enough. Thing is though, why don't we do rings in 4mm instead of 2.5mm? Because of cost, that's why. And if your wiring a lot of houses that's going to be a lot of wasted money. If customer is willing to pay the extra i.e. maybe £45, let's say, instead of £30 then yes, do it in 10mm. Diversity is covered in the On-site guide.

[@smartchip]

cater4anytink checkout the best sparky in the U.K. he knows the regs in his head, can tell you the reg and the page its on, his name is john Collins, his training place is in dudley West Midlands, he is a great trainer, he used to teach at sbc college, he teaches in small groups, like two! On different meters, as everyone has different meters, etc, everyone knows him, especially the regs guys, ex military,

[@kangtheconqueror]

smartchip John Collins? Ha, ha... you mean 'Johnnie Ace'!! Oh, he's great. I love watching his vids. Very knowledgeable and puts things over in a way anyone can understand. Johnnie Ace, (tsk,tsk), is on the case. That's a great catchphrase. 👍🏼

[@stevencorbin103]

smartchip what's his youtube page. Cheers.

[@joshtaylor1065]

How does the location of the cable determine the amperage of the cable?

[@finbarrdolan]

Will a modern stand alone single oven work off a 16 amp circuit or do you need to charge out the circuit breaker on the consumer unit for a 32 amp circuit breaker ? Thanks.

[@user-yh4kl3hx2o]

Your a legend no other words....amazingly trained and educated

[@uthmanzubairoluwatos]

Sir, the table says 6mm^2, which is suppose to be cross-section area, but you are using it directly as a diameter. Please explain.

[@davidbrewer7937]

You must also remember that current ratings for wires depends on their situation & bundling. This is because cables dissipate heat under normal operation & constricting those cables or clipping them tightly has a different effect than their ability to dissipate this heat as does their placement in insulation vs hanging in a free ventilated area....In short, it is best to select a cable for the application with the matching breaker which is at least 30% larger than the worst case scenario of the application.

[@tmengistu1778]

Great thoughts!

[@matthewrichardson3482]

No diversity applied or what about whether the Zs reading complies. Good video but still needs more to fully explain the full process including the testing after installation to ensure the install complies and gets the all important certification.

[@ahmedelectricianofiraq5550]

i now 1mm cu wire can hold max 8 amp without voltage drop 0.05% in lenth 100 meter and don't get hot so (1mm 8amp) , (1.5mm 12amp) , ( 2.5mm 20amp) , (4mm 32amp) , (6mm 48amp) , (10mm 80amp) , (16mm 128amp) and thanks for your great video.

[@firsteerr]

hold on , you should also take in to account the method of installation , the various conditions it will pass through (example , you may go through insulation and then into free air which operate at different temperatures

[@phasorsystems6873]

Create some circuits! chase down circuit solver on the playstore!

[@empratoreyaweb9003]

Thank you for yoir explanation, I only have one note: When you get the current you divided power over voltage without the power factor.. it should be P/(V*pf) so the current will be 48 A , then you should select a cable size according to that.

[@kkpropertysolutions3785]

You missed Diversity ,all you need for that it’s 32A beaker and 4 mill. cable if clipped direct.

[@scottsaul]

New subscriber thanks its all coming back to me😂

[@MrPantss]

But you have not accounted for diversity?

[@vikingofengland]

I have measured the voltage at the CU main switch in my house at 242v, yet I often hear that the UK is 230v?

[@piotrf7648]

All good pal,+- 10% tolerance so even 250v you can meet or 216for example.

[@martinmalone6324]

@@piotrf7648 looking for this reply as I thought it was 230 to 240 volts in the uk

[@KaVinceTV]

Sir thank you very much for the very clear explanation tutorials on how to calculate electrical wiring.

[@eija25]

45 A CB rating is too close to 44 A load, can get overheated during operation.

[@londontrada]

Nah, she'll be good

[@spencerwilton5831]

Kentucky Fried Jesus on large appliances in the manufacturer specifies the breaker to be used normally. Too small and it may overheat, too large and you risk it not performing as intended as I'm sure you know. They consider diversity and also often use various internal circuitry to manage loads, especially in the case of things like large range cookers with 6 or 8 Rings, two ovens, separate grill etc- in theory these could draw 80 plus amps, but with diversity and power management (reducing power to rings when all on) they may specify a 60 amp breaker. In these cases the electrician would not be expected to understand the precise workings of each particular model, so the appliance comes with a table indicating cable and mcb size often under various circumstances.

[@odoohub5010]

Is there any difference between rating a cable in mm or mm2?

[@tiezhongchi]

thanks to share the power cable information for tips . as an wire and cable making supplier in China that we learn a lot from your channel

[@SilasWanyonyi-o1w]

I am interested with your lesson iwould like to be your new student

[@callmejt2407]

Great video this will defo help with my studying

[@jeetenderkakkar7570]

Studing

[@radoslawrachwal6897]

What cable would you use on circuit where there will be washing machine and tumble dryer together. And sometimes Will be turn at same time?

[@ifitistobeitisuptome]

Excellent video, Thank you.

[@geoffreybasiamisi2668]

thanks for the fantastic lesson, I'm in Botswana

[@alunroberts1439]

Lighting is always 1.5mm but we do use 1mm down to the switch.

[@JaykeSapalaran-iq3qs]

Great video tutorial ❤ very informative. What title and who is the author of the book that you use for reference ❤🎉

[@carloscarrillo6493]

Not good reference for the US...! Use US Measurements...!