Thank you Andy. You inspired me to dig out my digital caliper which I bought 2 years ago on an impulse buy from Lidl and never used. I now know the cross sectional area of my existing shower cable and know the max kW of the replacement shower that I can choose.
thanks for the informative video. Its easier to use the following formula Area=(pi x D2)/4. You don't have to work out radius value then. e.g. A = (3.142x1.05x1.05)/4 = 0.86. then multiply this value by the number of stands.
I find an easier way is to measure diameter X diameter X 0.7854 to find square area of a circle. It is easy to remember as the keys are in the right order on a calculator already 78 54 it is a circular pattern on the keypad of all calculators.
Interesting, thanks. Slight suggestion would be to write the cable size / width as mm and not m - sorry, my maths teacher would have had us up for that!
Great video. I have question though. I see that you measured the individual strands. If it were a larger cable, could you measure the full conductor with all strands together? Surely you would know roughly the size as there is a large gap in between cable sizes on the larger ones. E.g 95.0mmsq 120mmsq 150mmsq, or would it not work like that?
Thank you SIR.... now i can check if the electrician use the proper receptacle for my well water pump and maybe this is the reason why my fuse keep burning and i just keep using type D before something worse may happen...and maybe get a referral as someone else mentioned to me
Hi a question if ok. I worked for a company 40yrs ago, AWA at North Ryde near Sydney. They sold a heap of excess rolls of cable 50m to 100m for $1 a roll (to cover the paperwork lol), naturally l bought heaps. I'm wiring up a 12v camping battery box looking at using this red and black cable. The information on the label: Pirelli Ericsson Single core 1 x 2.5mm 50/0.25 Grade: PVC Tinned Copper Max temp: 105c How many amps would this carry in a 12v application? Thank you for your time. Cheers
Steve, difficult to answer, if the able was 2 inches long it would be a 200 amp fuse (guessing), so the length of the cable makes a huge difference. It's all about the resistance and heat. I would guess about 5 amps but look up "Ohms wheel" for all the calculation formulas. Cheers
I'm a bit confused about some 3 core flex I bought to re-wire a lamp - I measured the bundled copper strands at about 1.5mm per bundle, multiplied that etc and got about 1.76mm2 as the cross sectional area but the wire is actually marked and it says 0.75mm2 on it. So I guess I've misunderstood something somewhere? Well, turns out I only need 2 core as the lamp body isn't metal, so I was just looking to buy some more, but then when confronted with multiple size options I then searched out this video to try to understand that.
Afternoon Andy. Very helpful, but wish you had a better cemera, I think you do these days. The second cable, all the wires will be in contact along the length of the cable. So like you I would call that final figure the capability of that cable, then fry my brain converting that to AWG or some other insane chart, to work out at the voltage (generally around 12v with my solar shed) how long that can be without significant Vdrop/load. From a chart. My Q is if the conductors are insulated from each other (eg 'borrowed' 2 core electrical cable from a dead strimmer), can I treat the two cores as 'one' cable, twist together the two, bared multi strand wires at the ends and class that as my cross sectional area. I kind of know I should be forking out for 'solar panel cable' but wire is wire, reight? ;) Eg, + from solar panel 100w, is one twisted pair old strimmer cable, - from solar panel is another. I wouldnt do this for big loads, like to an inverter, or between batteries (I would buy recomended cable for that short lengts) or use thick multi strand like you have in 2nd example. But where I have multiple 100w panels, in various places, and loads of 'borrowed' two core mains cable from strimmer, mowers and the like, seems a shame to waste it. In summery, does the individual cables (strimmer) being insulated from each other make a difference?
Hi, I'd say this video may be eight years old and the quality has changed since As far as doubling up cores in a cable and using the whole as one, no worries for low voltages. On high voltage DC it leaks through insulation, that's why solar cable is fine multi stand and double insulated, cheers
@@TheInfoworks Thanks so much for your quick reply. Puzzled me for years that question has, always thought it would be fine at 12v, 21v at single panel. All good, thank you. Crickey, it's only for my shed solar, hence saving a few bob doubling lines to the panels in different places to catch sun at different times. Wired parralel. Shed is in a hollow/shade.
Dear Andy please clarify me of the wire you measured first which is 2 core or single core? Moreover, I have seen a wire in my showroom in which they mentioned "3C x 18/0.2mm" what this is actually stand for and how to calculate the area with this given data? please reply
Hi. The first cable was indeed 2 core. This grey flat cable has 2 seprate conductors plus an earth. Commonly cxalled twin and earth. I can only guess as to your cable but 18 / 0.2mm would probably mean 18 strands of 0.2mm cross section area. You could have worked this out yourself by counting the strands and working out the area. Cheers
Andy Reynolds No I didn't...but I have to. But my confusion is the cable is 3 core 1) phase 2) neutral 3) earth. But in the purchase invoice they mentioned it as 1.5mm cable...in the cable as per the data while working out it comes 3.124 x 0.1x0.1x18 = 0.56 then how come the cable size be 1.5mm ????
Hi. This is obvoiusly desined as a flexible cable. As to the size it would be prudent to contact your supplier as there may have been a mistake. Cheers
Andy Reynolds you're right bcoz when I calculate with this given data the answer is 0.56 per core but they mentioned 1.5mm in the purchase invoice so I think I'd better contact the supplier...Thanks for you advice
so ive just measured my shower supply cable, its 7 strands and i measured 2 strands and got 1.42 and 1.64 so will call it 1.5 average per strand. i got the following doing (pi r2)/4x7, 12.37mm as my cable , so this isnt a 6mm cable and will take a 10.5kw shower ok? am I right? I want to buy the stronger shower and not the 8.5kw thats already there from the previous owner. i see i need 10mm cable for a 10.5kw shower
Hi, a 10.5Kw shower is a very energy intense for these climate change days and will draw at least 42 amps at 240v. The longer the cable the greater the resistance and so the bigger the cable, and there is the duty cycle to consider, if it is used for a minute then there is less heat build up that a 20 minute use. Select the right cable for the job. Cheers
if I may ask plz , here in U.A.E. printing in cable sizes is mm2 but when I compare that with AWG its completely different .,yes all tables in google that I checked are the same value but how I can my cable here wich is written mm2 as an AWG?
Technically speaking Andy you are slightly incorrect in the way in which you calculate the area of a circle. The formula is indeed πR2 but, technically, this actually means π x (R2) i.e. 3.142 (which is Pi to 3 decimal places which is the accepted norm and as you have used) multiplied by R2 (radius squared. i.e. in your example 0.52 x 0.52). And so, technically, the result of your calculation is derived by multiplying 3.142 by 0.2704 (the radius multiplied by itself). The result is the same as you showed, 0.8495968 which you sensibly rounded up to 0.85. I know that you reached the correct answer and that I am being pedantic but I thought that I should point out the correct way to calculate the area of a circle.
Same here..... I learnt to multiply the radius by itself, then, multiply by Pi (in my case, always just 3.142). It works well for me for all sorts of measurements, from 1mm wire all the way up to1.2M (1200mm) concrete pipes
Hi Andy I have a 2.5mm twin and earth drum where the earth should be 1.5mm. I have used digital calipers to measure the earth and the measurement is 1.1mm not 1.5mm. I need to verify whether or not the earth is smaller than should be. Am I calculating this wrong, do I need to do a specific calculation seeing as it's a single core not stranded.
@TheInfoworks so wrong though - was speaking to technical at one of the reputable bodies ans even they were shocked! Thing is it can make a difference when getting end to end readings and using your predicted cpc to determine a healthy or not healthy rfc
@@TheInfoworks orite.. so the first cable have 2 core .. so the 6mm for the first calculation actually for whole size of 2 core cable or 6mm only size for 1 core?
5.95 is = to the electrical wire size that you have to measure before deciding if that what fits your fuse box needs....and you need to round it up to 6mm2
