There is no problem with the calculation of your expected Zs, this is correct.
For the adiabatic part I think this needs some thought about how you are calculating this value.
You have selected 2.5mm² as a cpc size and put that into the t=k²S²/I² equation and got 0.21s, this is all OK.
However...
I think that if you have put this much effort in and can describe why you are doing these things then you should at least gain a lot of marks for effort, even if it turns out the final figure is in error. But at least you know it will be suitable from table 54.7.
With only the information from...
You have not actually asked a question there, this diagram shows my thoughts but you will have to check and ensure that you understand and agree with these designations.
Somewhat odd advice perhaps, I must be missing something.
I can only think they mean determine cable size from breaker size and Zs
R1+R2 maximum value is straightforward
Minimum cable size to meet breaker rating would work, and then compare to required R1+R2.
Then with cable selected R1+R2 and...
First part all OK, much better choices even though the other choices were possible, this is in keeping with the information in the question that states the protective device is 16A.
For a type B MCB the highest current required to ensure magnetic trip is 5 times rating, 5*16 = 80A. With the 80A...
The point on the ring where the fuse is positioned must meet the ADS requirements for the ring.
After the fuse it is preferable but not required to continue the protection from the ring protective device. However if the resistance of the spur after the fuse exceeds the maximum Zs required for...
This light is presumably the end of that block of lights as all the others work.
The voltage (60V) seen is spurious and meaningless, it just indicates it is near some power.
The switched line is disconnected between the previous light and this light, because the control gear have just been...
You are certainly working hard on this one. We do not have the full information from the question and scenario to be able to fully calculate the results and doing this would not help you to progress so I am going to try some suggestions that may not match with the scenario but might give you an...
The on site guide only gives the advice that on insulation resistance testing that the switches must be operated one at a time and further measurements taken (not very specific!). Your training provider should advise you on their approved method for you to use in training.
When actually doing...
I would be tempted to answer that the adiabatic at 80A and 0.1s gives 0.22mm², this would mean a 1mm² is possible but the minimum csa specified in table 52.3 for power circuits is 1.5mm² therefore a 1.5mm² cpc is the minimum suitable.
I am just pushing at the limits of what may be assumed, 701.32.1 specifies that the location can be effectively limited by walls, doors and windows.
Whether this can be applied to a cupboard door is debatable.:)
The calculation you have done for assessing compliance with the minimum Zs for a type B 16A BSEN60898 circuit breaker shows that the theoretical value is well inside the maximum limit of 2.73Ω at 70°C (normal operating temperature).
Your calculation for the adiabatic is flawed because the time...
Doors (if the cupboard has a door, but without a door it would be an alcove) limit the extent of a room containing a bath or shower so the socket is not in the bathroom but in a small area off the bathroom, a bit like having a socket on the wall just outside the bathroom door.
When you do the adiabatic equation you will get a value and you then select the next available cpc size that is greater than that value, e.g. if you get 1.6mm² as the result of the adiabatic equation you would use a 2.5mm² cpc, if the result was 1.4mm² then you could use 1.5mm² cpc.
Slightly more complex to answer this one as there is a practical approach and an approved testing approach!
In testing R1+R2 any reading on a light circuit, where the light would be on if the circuit were energised, should be substantially the same and all readings where the light would be off...
I would agree that the Zs value should be the 1.37Ω for the 32A MCB.
It would be possible to have a spur that is protected by ADS by the 13A fuse however it is better to have the whole circuit protected by the MCB at origin.
In doing the figure 8 measurements when you measure the resistance at...
A diagram to show the potential for overload as described by M-Ty using some possible current loads (obviously chosen to overload the cable)
You would have to work at it to overload but it is more likely and you would not need to overload the MCB to do it.
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