earth fault loop impedance

earth fault loop impedance

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  1. S

    UK Amtech/Trimble - Excessive Earth Loop Impedance on SWA cables

    Hi All, I'm new to Amtech/Trimble and I've been asked to review a model. I'm looking at circuits that are SWA cables using the armour and an internal conductor as the CPC. There are various earth loop impedance errors listed where the Zs at the load end is too high, but what I can tell, Amtech...
  2. sakurakey13

    Level 3 Design Project - How to calculate Zs?

    So I’m doing my level 3 design project at the moment, and I’m on the question where you do all the calculations on each circuit, I’ve taken the max earth impedance from the regs, but it’s asking me for the earth fault loop impedance of the circuit. I think it’s asking me to calculate it, and I...
  3. J

    UK Earth loop fault impedance help

    Hello I’m a student learning about industrial wiring and circuits and we’re about to start learning about how to do loop impedance calculations. I have made a drawing of a three phase installation and was wondering if anyone could give me information on how I get the Ze Zs and R1 + R2. How would...
  4. Mark Wright

    Max Earth Fault Loop Impedance for OverCurrent Devices Before Amendment 3 and Now???

    Maximum Earth Fault Loop Impedance for OverCurrent Device was calculated 230/(MCB Rating*5) * Rule of Thumb is that correct? And how are they worked out now after Amendment 3?
  5. A

    Earth Fault Loop Impedance Test for lighting circuits

    Hello guys, Do you do Earth fault loop impedance test for lighting circuits during periodic inspection ? do you measure it at the lighting point? what is the percentage of lights you test? Thanks alot in advance
  6. K

    AM2 testing

    Hi everyone, a few questions here Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result...
  7. J

    Earth Fault Loop Impedance...

    Hi there, I’m just hoping someone could clear something up for me at all. I’m just working my way through some test questions and I’ve come across one in which isn’t making sense to me. Q. Calculate the maximum earth fault loop impedance permissible for a 30mA RCD used to protect a circuit...
  8. C

    AFDDs are a massive fraud

    Derailed another thread with AFDDs, so I am starting this one. I will simply say that UK RCDs and MCBs provide arc fault protection as is. UL not only knows that, but extensively researched UK power systems in an effort to emulate the very same concept 40 years. One the simply fact (growing...
  9. M

    Excessive earth fault loop impedance

    I work for a hotel chain and recently we’ve had our 5 yearly test they have 8 circuits from our LV panel with excessive loop impedance readings !! So apart from either introducing an rcd or dropping mcb ratings or type is there any other way of achieving satisfactory readings ?? Also if I have a...
  10. S

    Earth fault loop impedance

    Morning all. So just trying to refresh my grey matter but having a biff moment. Earth fault loop impedance with circuits protected by BS EN60898 type B circuit breakers. I know the tabulated values are in table 41.3, but for the life of me I’ve forgotten how to calculate if acceptable or not. So...
  11. LewisM

    6A MCB Tripping on Earth Fault Loop Impedance Test

    Hi, just finished a partial rewire at my sisters house and when testing the two lighting circuits (up&down) the 6AMCB trips for both circuits individually, I thought the MCBs might just be sensitive to the test but the smoke alarm circuit also 6A is fine when testing, R1+R2 and IR test all fine...
  12. Gary Tollison

    Earth fault loop impedance, initial verification, multiple DB

    Hello. Not sure if this is the correct forum to post this in (still trying to work out where the trainee section is). Just been doing some practice fault-finding online. Found this scenario: After doing initial verification on an outbuilding with its own DB, which is supplied from the main DB...
  13. N

    earth fault loop impedance calculation

    hello all could anyone help me i am doing my 2392 and i am a little stuck i have been asked a question which is using the following measured value of loop impedance 0.5 (40amp bs en 60898 type b mcb) ferfering to the maxium tabulated value given 1.15 show by calculation if the measured value is...
  14. Gary Tollison

    Earth fault loop impedance - textbook values vs BS7671

    Hello. I'm in the final stages of completing my electrician course, and I find myself confused (again) by EFLI. In the textbook provided is this: Uo 230V see below for each circuit. Calculate the maximum Zs for each circuit: Complete the table. The answers given in the textbook are said to...
  15. Gary Tollison

    earth fault loop impedance

    Hello :) I'm confused about EFLI which I am guessing should be relatively straight-forward. I can't get my tired brain to figure out how to calculate the value for EFLI on system-side circuits? eg: what should the actual calculated value be for a 40A circuit, and how do I get that figure...
  16. Pete999

    Pete's Videos Earth Fault Loop Impedance, who needs it?

  17. gazdkw82

    Earth fault loop impedance

    Iv been given the scenario: 6 circuit earth fault loop impedance values were recorded. Each circuit has type B cb. referring to the maximum values, show by calculation if these values are acceptable. so I can't do zs =ze+R1/R2 because they've not provided me with ze. doing some research it...
  18. G

    Earth fault loop impedance

    How does earth fault loop impedance and disconnect time requirements change for 3phase 3 wire 230 volt systems where the phase to earth voltage is 133 volts instead of 230 volts?
  19. P

    Earth Fault Loop Impedance

    Hi all, I am hoping someone can clarify if my understanding on earth fault loop impedance testing is correct. A low efli is needed so a protective decive can operate in the required time, the lower the z the quicker it will operate. ZE= External resistance from borad to supply, board...
  20. spud1

    High Earth Fault Loop Impedance readings caused by RCDs

    Hi everybody, I have encountered a problem with EFL (Zs) testing a couple of times recently. I have had unusually high readings for the length of circuit and earthing system type and the increase in impedance seems to be coming from resistance across the line pole of the RCD in the consumer...

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