u/joblesdude

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Hello,

I'm struggling in question 5 of assignment number 615, and I need help figuring out where my mistake is. So here is a breakdown of what I have done, Step by step.

The question is: Determine, for one of the circuits supplying the fridges, the minimum possible cross sectional area of cpc which will satisfy the requirements disconnection as ADS under earth fault conditions and the adiabatic

equation as Regulation 543.1.3 in BS 7671.

Here is my attempt at it:

Step one - Table I1 in the onsite guide, the R1+R2/metre for a 4mm2 line conductor and a 4mm2 protective conductor is 4.61 R1+R2/metre + 4.61 R1+R2/metre = 9.22 R1+R2/metre

Step two - using the formula, from book 2 of electrical installations page 313, R1+R2 = R1+R2/metre × length × I3 factor / 1000

R1+R2 = 9.22 × 2.25 × 1.2 / 1000 = 0.0249

R1+R2 = 0.0249

Step three - Zs = Ze + (R1+R2)

Zs = 0.11 + 0.0249 = 0.1349

Zs = 0.1349

Step four - I = U/Zs

230/0.1349 = 1704.97

Step five - using the Adiabatic equation

√(I²)×t/K=s

√(1704.97²) × 0.1 / 115 = 4.69

Step six - Choosing the suitable CPC size would be 6mm2

The line conductor size is 4mm2, and the length of the circuit is 2.25 metres.

I'm really struggling to find my exact mistake, and I would really appreciate any help. Thank you all.

Hi,

I'm looking for a movie, unfortunately I only remember one short scene in that movie.

The scene where a car, I dont remember if it was a sports car or a truck, has to fight a huge enormous truck in a scene that looks like the scene from idiocracy where a tiny car fought a monster truck.

I dont remember who was in the car against the truck, but I remember them being shocked and scared.

Please help me, thank you

Found: "Herbie: Fully Loaded"

Morning all,

I have passed every single assignment/exam in level 3 2365 except the hotel design assignment, which I handed in last week.

I'm afraid the grading process for the hotel assignment will take too long, and my course will end before I pass! My course will end on September.

What will happen if I didn't pass the hotel assignment before September? Will I have to start all over again?

I asked my college this, but they didn't give me a clear answer, and I'm really worried.

Hi,

I need an app just like Samsung notes for mobile but gives me higher quality when I want to print or turn it into a pdf. I need to be able to draw stuff.

I have done alot of work just to find out I cant make it a pdf with out the file losing all of its quality to the point its completely unreadable. I'm honestly so sad and devastated now.

I'm happy to receive all suggestions and help.

Thank you