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Again, thanks so much for your help, I thought I was gonna go mad as my tutor just finds it funny that it’s driving me crazy so throws bits in to confuse me 😪 now I can do I* X 0.1 / K? What’s that 0.95? Is this a factor for something? 

Does this mean as my fault current is higher than the 60A recommended for 0.1s disconnection time i can assume 0.1s in my calculation?

0.7s?

Mate i'm lost not gona lie 😪

Fig 3a5

60898 type c 1s? by following the graph?

k=115 S=1.5mm2 I = 396.5 1152 X 1.52 / 396.52 = 0.189s

This is exactly what I spoke to my tutor about, so the t=k2 X S2 / I2 calc is the maximum time the line conductor can withstand the fault for? is this correct? I feel so dumb right now

Ive just done the calc again going up in size until 4mm/4mm (R1+R2 = 9.22) This works but i feel as though 4mm is overkill surely?

So I just use the rule of thumb rule then? I initially done the calc using 1.5mm/1.5mm but as this was also coming out high I went around in circles with it. I just assumed i was doing something wrong and was afraid I was going to get "dumbed". Like i say ive followed the rest of the calcs the...

Yeah using adiabatic I’ve done the adiabatic with the Isc for R1+R2 1mm/1mm 1mm/1.5mm 1.5mm/1.5mm all came out higher than the line csa. All other calcs I’ve done have been ok.  k=115

Right so not 0.2s like I was informed 👍 even using 0.4s disconnection time my cpc is coming out larger than line conductor in the adiabatic even when stepping up the R1+R2 values given in I3 OSG 😪 Thanks so much for your replies btw!!! This has been causing me grief, making me feel like I...

Full cable calcs for the above circuit 😪 I’m lost as I’m being fed cross information. I thought for the adiabatic equation you have to work out  1) fault current 230/Zs 2) disconnection time t= K*XS*/I*

This is what I put to my tutor who was flabbergasted by the t= equation. Do I need the t= equation as this would give me a time of around 0.1s

This is my headache, my tutor has said that disconnection time should be taken as 0.2 as it’s 3ph which I questioned as it’ll be the line voltage surely. The problem is every time i increase line size R1+R2 values to say 1.5/1.5 which I thought would be sufficient my cpc size is still coming out...

Hi all, really hope someone can help me as I am doing something wrong when it comes to cable calcs, I am currently working my way through my lvl 3 EAL. Would someone be able to work through this question so i can see where i am potentially going wrong. Thanks in advance. TN C S = 0.35 Ambient...