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calculating

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  1. C

    calculating cable size

    hi, i was wondering as i calculate the cable size of a run of swa do i use the total ampage or the line ampage? for example my run is 95 meters and total current is 273 amp. the cable is spaced in horizontal cable tray.
  2. A

    Calculating power factor with wattage and voltage

    Hello, I really need to know if it's possible to calculate the power factor from the voltage and the wattage... For example... 13kW, 400 V three-phase machine Thank you
  3. P

    Calculating total demand and diversity in single phase+three phase circuits.

    Good evening all, I just joined the community and I really hope I can contribute as much as I could be helped. Really. I'm completing my 2365 lvl3 course however I just got my 305 B assessment paper back. Apparently I didn't calculate well the max. Demand and diversity of a given circuit...
  4. Robertbaker63

    calculating demand

    a local pub i do alot of work for wants to build 6 pod style holiday lets in its beer garden and has applied to western power to see if the existing supply can cope with the demand the existing supply is 2 phase with a 200 amp fuse in each phase leading to a busbar system. ive been asked to...
  5. U

    Calculating Zs for known and unknown cable length.

    Hi guys, Am I doing Continuity test calculations in a right way? For unknown length of a cable: Circuit breaker B16A, let Ze be 0.26 ohms. Zs from Table B6 (OSG, p125). MAX Zs-Ze = Max expected (R1 + R2) = 2.2 - 0.26 = 1.94 ohms For known length: Let's assume the cable is twin with 1.5x1.5mm2...
  6. S

    The regulations with regards to calculating Zs and Industry Good Practice.

    Hello Gents Once again I’m looking for your expertise to resolve the following application. A local supply Authority has supplied a single phase 8Kw TN-C-S supply via a cut out, to which we have to terminate a 35mm2 3 core SWA cable to be buried underground. The cable cannot be easily...
  7. Q

    Calculating inverter for motor

    Dear All, I have a problem. It's calculating inverter for 3 pharse non-synchronous. I mean that i don't know the formula. My colleagues show Here we go : P1/P2 = (n1/n2)3 Please help me out Thanks
  8. A

    calculating the resistivity of two layer soil

    Good evening!! i have recently been looking into earth electrode systems, which got me onto reading BS 7430:2011. I am hoping that someone on here can clear a few things up for me. First of all, is there a reason why BS 7430:2011 makes no reference at all to non homogeneous soil types? It...
  9. H

    Hourly rate after calculating overheads. Opinions please!!!

    Hi guys, After sitting down and working out all my fixed and variable overheads I have worked out charging a maximum hourly rate of £28-30 per hour working 220 days of the year. If I only worked 150 days of the year, as this is my first year trading, I will need to charge £33 per hour. I have...
  10. The Solar King

    Calculating Payback and Yield for Private Customers

    Feed in Tariff and Export Tariff payments are Tax free. When calculating pay back does anyone take this into account? The payment is effectively what would have been received after tax was deducted had it been taxable. For a 20% tax payer, it means the payment is actually worth 25% more. For the...
  11. B

    calculating rates and business plan

    I have a question.I have seen plenty of people ask here how much they should charge for certain things in their business. I have also seen plenty of men ask here ask various other questions about starting out and other related questions. I would like to know how many of you would find a book or...
  12. A

    Calculating external R1 & R2

    Is there any way of calculating the r2 and r1 values of Ze for touch voltage calculations many thanks
  13. S

    HELP! calculating ze

    Is it possible to calculate Ze? I am in the middle of an assignment, and have this question to answer. When confirming automatic disconnection of the supply it is necessary to determine the external earth fault loop impedance(Ze) of the system. State three methods by which this can be...
  14. S

    Calculating Zs

    I need to calculate the Zs for a ring main that uses the metal conduit as CPC. I know that Zs = Ze + R1R2 but I only have an R2 reading as there is no wired CPC. Anyone got a clue?
  15. Simonslimline

    Calculating Neutral current in unbalanced TP

    I have been looking at this today and found it interesting so thought i would post a question for any of you to answer. Calculate the neutral current on a lv 3 phase system. L1 = 30Amps L2 = 60Amps L3 = 22Amps.
  16. D

    Calculating 3 phase current

    I understand that the formula to work out a 3 phase current is I= P/(1.732 * V * pf) I have a 3 PH+N water pump rated at 4kw, so I= 4000/ (1.732 x 400 x 0.8) I= 4000/554.24 I= 7.21 Amps per phase The problem I have is that the label on the pump control says that its rated current is...
  17. J

    New Zealand calculating main earth size

    i am just a little unsure if i need to use 5 seconds as my D/T or 0.4? PFC obtained through Ze test at origin. i have been told 2 different answers and any guidance would be helpful. thanks james
  18. F

    Calculating Voltage Drop on a Ring main

    Hi Guys, I'm fairly new to the industry and have sat and passed all the relevant exams to become a Domestic installer. I'm a little stuck with one of my pieces to be assessed by NICEIC. I'm doing a full rewire at my dads house and would like to check that I'm calculating the cable volt drop...
  19. N

    Calculating Zs!

    Just a quick check to see if my math's are right for NVQ3 assessment. Ze - 0.01 Ohms Circuit length - 28m CSA of line and cpc - 2.5mm2 Conductor material - Copper R1=pL/A R1=((1.78x10-8)x 28) / (2.5 x10-6) R1=0.19Ohms R2=pL/A R2=((1.78x10-8)x 28) / (2.5 x10-6) R2=0.19Ohms Zs= Ze +...
  20. J

    little help with volt drop calc

    Hi everyone just a little confused,when calculating volt drop using table 4Ab do you measure the voltage of the installation and use that value to calculate or do you just use the 230 volt value

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