calculation

calculation

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  1. K

    Circuit design calculation

    I have a question i hope someone can just give me a little clarification on . When carrying out preliminary cable design for a given circuit we use this formula = ( milliohms per metre x Length x multiplier Factor for maximum operating temperature ). Do we still need to use the the maximum...
  2. 2

    Calculation submain cables

    Hi. Im looking for some advice when calculating submain cables. Basically there is a new connection of 80Amps that is to be used for a dwelling and a small workshop. I had thought taking to a feeder box with one submain and then two feeds away into the buildings. A direct run from dno to...
  3. A

    Cable sizing calculation

    Happy New Year all. Quick question regarding cable sizing. I have a 25m run from DB to car charging unit. The 25m run will mean approx 8m is run in the attic, 6m is run clipped direct down and across a wall and the remaining 10-11m will be buried underground in a 2 inch duct to the car charging...
  4. J

    2396 - Calculated Zs value

    Hi All, Any help would be greatly appreciated. When calculating the Zs for a circuit specifically for 2396 do you have to incorporate the on site guide multiplier tables I2 and I3? It seems to be dependant on what training material you use.
  5. H

    Loop impedance calculation

    Hi all , The measured value of loop impedance for a circuit is 2.4Ω. If the temperature at the time of the test was 20°C and the cable is 70°C (factor 1.2) what is the corrected value. Ze = 0.4Ω: the answer that I got is 2.8 but according to my calculations it would be 2.88 ohms follow up my...
  6. Aaronj46

    A722.3 Formula/ Calculation?

    Max resistance for an EV earth rod. Would anyone be able to break the formula down or direct me to a video etc with a sample? I'm booked on the 2921 at the end of the month. I have the 18th & IET 4th edition available if someone could point me to the right place?
  7. T

    Load Calculation Help

    Hi there, I'm looking for someone to take a look over this load calculation I've done to see if it checks out. I'm using the Optional Method. I'm looking to add an induction cooktop (shown in red) and it seems like it should just fit on my 200A service. The main question I have is if I can...
  8. B

    3 phase voltage drop calculation?

    Hi! Once you've calculated the voltage drop in Volts - you divide by 400V for three phase right? For example: three phase 30kW appliance, 10mm 90 degree SWA, 45 meter run. 30,000/sqrt3/400 = 43.3A = Ib from the table 4E4B, a 10mm cable gives 4.7 So then 43.3 x 4.7 x the 45 meter run gives =...
  9. S

    What am I doing wrong with this calculation?

    I have been going round in circles with this question. I just cant seem to get an answer remotely close to the options. Continuity of a ring final circuit has been tested as part of an initial verification of a new primary school. All the socket outlets are connected directly to a ring. The...
  10. G

    Help with cable calculation please

    Hi Help please with the adiabatic I am doing a small design for my course and I can't figure it out. Any advice will be appreciated. Ring Final Ib: 30A In: 32A It: 20A Iz: 21A 2.5T&E method 100 V: 229V Ze- 0.22 Ohm L: 26m So r1+r2 = 19.51*26*1.2/1000=0.6 Ohm. R1+R2 = 0.6/4 = 0.15ohm...
  11. I

    Cable Calculation Help - Adiabatic Equation

    Need help check that my cable calculations are correct as still new to doing them. 6A Lighting Circuit 60898 MCB Type B wiring in 1MM²/1MM² T+E supplying a single 10W outdoor light Length = 3.3M Zs@db = 0.22 R1 + R2 mΩ/M = 36.20 mΩ/M - Table lt P218 OSG Correction Factor - 1.2 - Table L3...
  12. CristiP

    Cable calculation exercise

    can anyone help me with this problem ? i don't understand it ive triend to get involved in it but still i don't get it thanks
  13. L

    Industrial socket cable calculation

    Hi, I have a question regarding the cable size to a 415v 125A socket. For the design current is it normal to use the protective device rating of 125A as the design current for the calc? Thank you
  14. L

    Calculation question.

    Hello, I have a question about diversity and load utilisation factor with Trimble software. Say we have a 3ph 150kW load with 0.8 pf which gives 187.5 kVA and we also have a diversity of 0.8 and a load utilisation factor of 0.9. Applying these factors we will end up with a kVA of 135kVA...
  15. L

    IT earthing system cable calculation

    Hello, Does anyone know if Trimble can be used for cable calculations for equipment with an IT earthing system? If not could you please point me in the direction of an example calculation if possible. Thank you
  16. Rockingit

    Calculation of VD within/as well the adiabatic?

    Here’s something I’ve never thought about until now…. So, we use the adiabatic to return an S based on the usual parameters and for arguments sake we end up with a 35mm conductor. But what if it’s also 300m+ length end to end before the earthing conductor gets to the MET? Do we then also...
  17. M

    Solar panel calculation

    Hi First time poster, I have a 250w solar panel and a 90ah 12v battery. What size regulator / controller do I need please? Is it as simple as connecting the controller between panel and battery? Can you use standard flex? Thanks in advance
  18. E

    Electric furnace wired breaker calculation (canada)

    Hi, can anybody walk me through on the CEC side on figuring out the breaker and wire size for a 240V, 15.7kW electric furnace. I am an electrician and have not worked on residential for a while. Thank you.
  19. M

    Calculation of resistors for premagnetizing a transformer

    Existing situation: 3150kVA transformer, 11kV/450V no load losses 6300W. Existing premagnetizing resistors with power losses 322kW for 5s. Due to increase in power demand, a new transformer has to be installed: 11kV/470V no load losses 8500W. Would the above mentioned resistors be enough? And...
  20. KeenPensioner

    Cable calculation parameters

    Hi, as I've said many times on this forum, I'm not an electrician and now retired. I'm still keen to learn and spend a lot of time studying all things electrical (especially during this lock down madness - it keeps my brain active!!). Anyway - I understand what Ib and In are and how they...

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