loop impedance | Page 4

loop impedance

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  1. V

    External earth fault loop impedance Ze

    Hi all Just checking this procedure is correct for Ze This is a live test so with the consumer unti front off i would lock off main switch keep RCDs on and all MCBs on. Dissconnect the main earth. Now on the megger 1553 i would set it to no trip and use the 3 lead method ? So green...
  2. E

    Calculating earth loop impedance

    Hi all R1 + R2 +Ze this equates to Zs but does this also equal the earth loop impedance, can I calculate ELI instead of measuring it, or are there other factors involved?
  3. L

    The value of Ze on a TNS system useing an earth loop impedance test Instrument

    The value of Ze on a TNS system useing an earth loop impedance test Instrument list the steps in the procedure and the reasons for each step, I think this is right ? 1.Select appropriate test Instrument - It needs to be able to read Ze (low ohms resitance metere ?) 2. Perform safety check (...
  4. 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) =...
  5. 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...
  6. 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...
  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. 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:
  10. 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?
  11. 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?
  12. 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...
  13. 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.
  14. W

    Earth fault loop impedance reading on TT System in domestic premises

    Hi All , I am new to this forum but am an industrial electrician (20 years) but have been using my Robin KTS1620 Multi tester in my house to do a few tests as i am considering returning to partp work as my industrial work is quiet. The house is supplied by a TT System through a 100mA RCD. I...
  15. E

    Max Loop impedance 1.44 or 1.16

    The Big Red book states 1.44 ohms for a 60898 / 61009 32a B rated breaker / RCBO The GN3 staes 1.16, I know this is allowing for temp rise on the faulty circuit but what do I put down on the Domestic installation cert, 1.44 or 1.16, according to Harry Hill there's only one to find out...
  16. K

    RCBO Max Earth Loop Impedance Readings

    Hi all, This is my first post on this forum, so please be easy on me.;) We currently have new Merlin Gerin consumer units installed within Aberdeen College, and looking at table 41.3 b the eli readings should be 0.72 minus rule of thumb. This fails most of the existing circuits. When i...
  17. S

    High Earth Loop Impedance

    Dear All A mate of mine recently asked me to look at his installation. It has been wired to the 17th edition and all looks kosher, but when I carried out some testing I discovered that it had High impedance values. I disconnected the Main earth that had been connected to an earth clamp, attached...
  18. S

    RCDs and high loop impedance

    Hello everyone I was wondering if it was possible in a TNCS system to add an RCD to a final circuit with a loop impedance exceeding the values stated in tables 41.2 - 41.3 to ensure fast enough disconnection during an earth fault. I had thought it was but if so why are RCBOs subject to the same...
  19. E

    Maximum earth loop impedance

    Table 41.3 gives the maximum earth loop impedance on a type B 32a breaker to 60898 as 1.44 ohms, the testing schedule on the domestic cert asks maximum permissble loop impedance, in the test and inspect notes I seem to remember that you are required to write the full 1.44 but I'm sure that you...
  20. D

    Help Please - max earth fault Loop Impedance value table needed urgently

    Hi everyone Would be really grateful for your help on this. I have my 1st NICEIC assessment on Monday (am bricking it) - anyhow I only have an old table & I need one like you get on the back of the proper NICEIC pads - the most up to date table. Has anyone got one they could send me so...

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