impedance | Page 6

impedance

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  1. A

    excessive earth loop impedance on final circuit

    Hi. This seems like a newbie question but please help. Received the test results with an 'excessive earth loop impedance' on one final circuit. Circuit originates with a 32A MCB and serves 10 socket points. Wiring is 2x2.5mm live, 2x2.5mm cpc. Max Zs = 0.72 Ohm. r1 (line) = 1.68, rn (neutral) =...
  2. L

    Things I cant work out

    When the emf in a conductor 0.15m long moving at right angles through a magnetic field, at a velocity of 2 m/s is 0.5 V, the magnetic flux density would be I know the answer is 3.17 T but i dont know how to work it out If a resistive and capacitive circuit has an impedance of 3 Ω and a...
  3. S

    Measuring electrode resistance to earth using loop impedance tester?

    I'm going to be fitting a new CCU where the earthing arrangements at the property are TT. Obviously I will need to measure the electrode resistance to earth and as I don't have an earth resistance tester I was hoping to do it as described below. I assume the result is the number I enter on the...
  4. M

    Earth Fault Impedance

    Can some one help sharing an example on how Earth Fault impedance can be calculated for an underfloor busbar. After testing the earth fault impedance for the circuit it is showing higher impedance than the max value. Thanks
  5. T

    Earth Fault Loop Impedance Ze test at origin

    Hi, I have a my am2 practical testing exam next week and I'm confused about the earth loop impedance test. The centre use a three lead instrument, I just want to know if this is right. Connect the third lead to the neutral bar, and connect one lead to the earth bar Then measure over the...
  6. J

    Wierd no trip impedance value

    Whilst testing the earth loop impedance on a circuit in a church the value given by the regular loop test is 1.74 but when doing it on non trip (with the neutral lead connected) we got >200. Has anyone any ideas on what could cause that? Thanks
  7. V

    Earth fault loop impedance

    Can somebody help me on how to test the earth fault loop impedance(Zs) of the following circuit Cooker,Immersion,motor .i have tried but the tester display :confused:
  8. B

    Loop impedance

    I was doing a Ze test today with my 1651 fluke and it was reading >2000 ohms. The main switch was isolated and the earth disconnected. I had the green probe crocked onto the TN-S clamp on the incoming main, the blue on the neutral bar and the red on the supply side of the main switch...
  9. L

    Testing Question!!!

    What is the difference between Ze and Zs??? As far as i thought i knew Ze is the circuits earth loop impedance and the Zs is the installations incoming loop impedance??Real confused?!?!?!
  10. D

    loop impedance

    Hi All Hope you can help me with this one, how would i calculate loop impedance on single phase and three phase generator :rolleyes:
  11. M

    impedance question

    A Capacitor of Capacitive Reactance 50 ohms, an inductor of 80ohms Inductive Reactance and a Resistor of 40ohm are connected in series to a 200v 50 Hz supply. The impedance of the circuit will be? i know the that z= square root of R squared + (xl - xc)2 but i cant seem to work this...
  12. D

    total circuit impedance????

    if anyone could help me with this i would really appreciate it. Q. A series a.c circuit has a resistance of 3ohms and an inductor of 0.0127 H connected across a supply frequency of 50hz. What it the total circuit impedance? the answer is 5ohms but i have no idea how to work it out...
  13. J

    earth loop impedance test

    Hi I must admit it has been years since I did this test State two conditions which were confirmed by the test instrumement before the Loop Impedance Test can proceed?
  14. C

    High earth impedance

    OK - discovered yesterday (when British Gas came to install my new boiler) that the earth is very poor, up near 100ohms. So I then start thinking and remember that the water pipe is now plastic and the earth comes from the water pipe. So, first of all can I confirm what type of earthing...
  15. H

    Is there any point testing earth loop impedance

    In a tt system? The earth spike is Reading greater than 50 ohms so clearly the mcbs won't make their rated disconnection times. Waste of time?
  16. C

    Impedance

    How do you do a test to find your impedance
  17. P

    loop impedance calculation

    hi i am doing 2330 and we have been given some calcs to do but the handouts they give are pretty poor i've had a go at the first one but need someone to tell me if i'm going wrong ( A downstairs lighting circuit of 90 metres is to be wired in 1mm thermoplastic (pvc) twin & cpc with an over...
  18. A

    Prospective Fault Current

    Hi Guys How do you calculate Prospective Fault Current?? Wouldi be correct in thinking it is nominal voltage divided by Zs + R1 + R2 ??? So Nominal Voltage Zs + R1 + R2 A
  19. J

    Earth fault Loop Impedance Question

    Hi All, Q: If an earth fault loop impedance instrument records a valve of 0.55Ω at 20°c, what is the corrected valve ( Using the rule of thumb method ) to allow for conductor maximum operating temperature? Any replies will be appreciated.
  20. O

    High Impedance Earthing - IT/Floating earth systems

    Q- Can anyone please explain the concept of high impedance earthing (IT) and floating earth concepts used on ships/vessels, and how it is achieved and monitored, Can anyone with the technical knowledge of this subject explain in simple terms please!

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