calculate

  1. C

    How do i calculate the total resistance in a series-parallel circuit?

    Hey, I'm an electrical engineer in training and i was wondering how you could calculate the total resistance in a series-parallel circuit? I attached a picture of what it looks like. If it's to any help resistor 1 is 2, r2 is 3, r3 is 4, r4 is 5 and r5 is 6 Ohm. Thanks for any help
  2. B

    How do I calculate the resistance of a spur without phisically testing ? ..

    Boffins of the electrical world ... How can I calculate the resistance of 48m ring 2.5/1.5 .. with a 8m spur .. I can quiet easily do this without a spur in the equation but , my test papers require my doing so with an 8m spur. . how does this affect the zs tests ... Thanks v much ...
  3. R

    Calculate device/battery run time

    Hello I am trying to calculate how long a car battery will last for which is 50ah, 12v. Running a 20watt device, 240v, turned on 24hours a day, how long would this battery last? Any help appreciated thanks
  4. spud1

    Can I calculate how fast an RCD should trip?

    Hi all. Been bugging me. I think there is a way to calculate how fast a particularly rated RCD should trip (rather than measuring) but I can't remember how to do it ? e. g. If I was designing an SWA submain fed from a TT earthed installation and I needed to install say a 300mA TD RCD to...
  5. N

    R1+R2 and Zs calculate acceptable?

    hello 1.is that acceptable if i do only Zs test last point of the lighting circuit and on scoket! instead of measure R1+R2? i can caluclate R1+R2 ACTUALY! ZS-ZE=R1+R2 is it acceptable to write the value on certificate? 2. as i know the maximum Zs by rcd (rcbo)protected circuit 1667 ohm...
  6. spud1

    Measure or calculate your Zs?

    Hi again! Which value is best to record in a certificate or report, a max measured or a calculated Zs? I know Sparkies who do it both ways, but personally I take measured values at all the points of utilization to find the highest, then I calculate Ze+(my highest R1+R2) for the circuit and...
  7. Lee Gold

    Calculate the resistance of a copper (annealed)

    what's the difference annealed? Calculate the resistance of a copper (annealed) conductor 35m long that has a C.S.A of 2.5mm2?
  8. T

    Calculate this...Part II some pics of the main cut-out and fuses

    Yeh so thought I would check the main fuses and still can't tell what rating they are. I did contact the man from the DNO who said no hurry the next few months will do. @Leesparkykent he did say there are no penalty charges right now but come April there will be. We spoke with the energy...
    • The Ghost
    • Thread
    • calculate fuses main part
    • Replies: 9
    • Forum: UK Electrical Forum
  9. T

    Calculate this. Just got this letter emailed to me...

    Errr I am going to contact the guy in the letter. This is not a new supply they have been supplying the place for 30 years to my knowledge. But do they really expect me to calculate the load on maybe 70 DBs and then apply diversity to 66 different businesses??? Bit of a tall order unless I am...
  10. A

    How to calculate the tabulated current (It) for circuits with multiple Reference Methods (A and B)?

    I am trying to select a suitable conductor size from Fig 4D1A of the BS 7671 Book, and am encountering a problem because the circuit does not conform to one Reference Method. The circuit conductors leave the distribution board in wall mounted steel trunking, then run through some steel conduit...
  11. L

    Distribution board checks

    Hi I have a question regarding switch boards and distribution boards. We have an existing switchboard and we want to use four spare ways in this to feed three new tp & n distribution boards. One for lighting one for small power one for security services. My question is what calculations have to...
  12. S

    Calculate time to recharge saxo battery with solar panel

    Good evening, i would like to know if someone knows how to calculate the time that would take to a solar panel of this kind Rotola in su pannelli solari produttore-Celle solari, pannello solare-Id prodotto:60489237141-italian.alibaba.com -...
  13. gazdkw82

    Parallel resistors

    I'm getting conflicting information regarding parallel resistors. I originally thought the below was how to calculate total parallel resistance 1. Rt= 1/R1+1/R2+1/R3 2. 1/Rt However in my pre exam workbook it says to 1. Calculate Rt as 1. above 2. Find the lowest common denominator 3...
  14. B

    Can you calculate ring final conductors if you have a measured R1 + R2?

    Hello there everyone, I've dead tested some ring mains on a job recently but unfortunately I didn't do my measured end to ends. The circuits only have two spurs on each. I have my R1 + R2's, it was wired in 4mm T and E so the earth is obviously 1.5mm. For example, if one circuit measured...
  15. S

    r1+r2. calculate or measure...

    Please discuss...
  16. H

    How to Calculate Solar Energy

    I want to design a solar panel about 10Kwh but i don't know How to Calculate Solar Energy. Please suggest me if any know about it.
    • harrydean4
    • Thread
    • calculate energy how to solar
    • Replies: 1
    • Forum: UK Electrical Forum
  17. B

    Calculate 3 phase amperage

    How do you calculate your amps for a 3 phase motor starter
    • brian.507679
    • Thread
    • 3 phase calculate currents motor phase plate rating
    • Replies: 9
    • Forum: UK Electrical Forum
  18. G

    how to calculate power of motor to b used ?

    Hi all, I need to know that if we have to install motor and a pumping set how would we know that how much horse power motor should b installed?
    • galaxyqueen
    • Thread
    • calculate how to motor power
    • Replies: 6
    • Forum: UK Electrical Forum
  19. Simonslimline

    Voltage Drop

    When selecting a cable and taking voltdrop in to acount is it 3% for lighting or 5% for other loads of 230v Because the voltage obviously changes from anything from 216V up to 253V. Thanks :)
  20. kingeri

    EFLI - measure or calculate?

    Just wondering what you guys generally do to determine the EFLI of a circuit during testing. Do you calculate it, as in Zs=Ze+(r1+r2), or do you measure for each circuit, or both. I tend to calculate it these days, simply as it's quicker, but just wondered what others do.
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