1. S

    High no trip earth loop readings

    Hi, I'm buying a new test kit and was wondering if anyone had a problem with non trip earth loop readings? This was taken on the same installation- new mk sentry split load rccb CU. I've got a secondhand, calibrated megger 1711 MFT which I've taken readings on a ring = 1.04 ohms And...
  2. M

    Loop tester different results

    Hello, I have a dedicated loop tester (Martindale EZ2500) and also a Fluke 1662 MFT The reason I have the additional loop tester is often at work I will need to measure P-E & P-N loop impedance only while I am in a harness climbing, or have walked for ages (large concert touring) the EZ2500...
  3. G

    Old Loop Circuit wiring to new light fitting

    I have a loop circuit in a 70's house and i am trying to fit a new light fitting to the old circit, i have wired it up so far so that the lights on the rest of the circuit work, but the one i am replacing doesnt work, please help, i have attached a image of the wires so far.
  4. M

    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. R

    USA Switch loop capabilities?

    Howdy, First encounter with switch loops. First situation is I have two lights that are apx 6 feet apart from one another and are on the same breaker. They have their own switch and both appear to be switch loops. The switch receptacle has two cables going to it that are 2.1(black white bare...
  6. D

    Loop at switch landing light

    Hi, had rewire, but didn't spec landing light that could be switched off from downstairs etc doh. Sparky said it's an easy thing to do, but will need to use wago boxes as he said no way to get all cables in back box even though they are deep ones. Mrs wants double gang, ie can switch both lights...
  7. M

    Loop Impedance tester electrical circuit

    Hi A quick one I was wondering if anyone knows how a multifunction tester performs a loop impedance test. I understand how to perform a test and what the results of a loop impedance test give you in working out your PSCC and earth fault current. I use my Fluke multifunction tester every day at...
  8. R

    Testing Loop Impedance through RCD.

    Hi, installed some circuits in a factory. The circuits were tapped off of a busbar that goes straight to the main switchgear. From this I installed a Chint RCD, which then goes to 2x Chint TP MCB and 1x Chint SP RCD. One of the TP MCB´s goes to red commando sockets and the SP MCB goes to blue...
  9. 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
  10. D

    Fire alarm loop test

    How to perform this test and it's resulted meaning
  11. B

    Loop Ceiling Light

    Hi, I am installing a new ceiling light. I know there s the wires from previous light and wires to next light and switch cables . One of the sets has two brown wires so not sure about these . Any help would be great . Thanks
  12. D

    Megger loop impedance irregularity

    Hi, I have a Megger mft1720 and the low current loop test isn’t working properly. Just wondering if anyone else has had issues? Readings are stupidly high compared to the high current test, and this can be made even worse if there’s an rcd in line......
  13. D

    Live Loop in the switch, how to extend?

    Hello, another can of worms that I have had the misfortune to find. The Mrs decided to take out a wall, and we need to move the existing light switches. I thought it would be a simple job but it looks like the switch has the live loop running through it. I need to move the switch and just...
  14. M

    Industrial 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...
  15. G

    Domestic I need advice with light loop

    Hi, I have just taken my light down to replace with a new one and noticed that the new one has no connection for the loop. Is it okay to just join the loop in a choc block inside the fitting, or do regulations state otherwise?
  16. B

    Loop in and out at switch

    Hi, looking to wire 3 gang switch loop in and out method 1st switch is One way 2nd switch is One way 3rd is Two way With my loop in, I go from 1st switch COM and link to 2nd switch COM then link to 3rd switch L1, all neutrals in a wago with my loop out in L1 also, then 1st switch T+E to light...
  17. Prytaneion

    Robin 4112 Phase Earth Loop Tester

    Hi Y'all, Any kind sparky know where I can get a manual for a Robin 4112 Earth Loop Imp Tester? Tried all the usual with no luck. Thanks guys.
  18. 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...
  19. 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...
  20. 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...
  21. T

    Potential earth loop impedance issues for second floor flat

    Hello! After years of renting I'm currently in the process of purchasing our first property. We've had an offer accepted on a 1 bedroom flat in Surrey. However there are questions over the electrics, and knowing little about electrical wiring I'm a bit stumped on how bad the electrics are and...
  22. Zdb

    Adiabatic equation infinite loop

    So I'm looking into the thermal constraints of every cable in my 2396 project. I've used the adiabatic equation in a spread sheet and 99% of them are fine with the CPC I have selected. However, there are a few really short circuits with very low earth fault loop impedance. Because of this the...
  23. 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...
  24. Just4MeDad

    For Sale - Megger LTW 325 Loop Tester (2 wire)

    Excellent condition, full working order, manuals etc. Located Chippenham, Wiltshire, will post. Offers around £225. :)
  25. T

    I can now do a junction "box" mf in 20 secs, switch loop and feed

    So, although as you know, I am not a tool tart I have invested in this little time saver. As you can see from the piccy you have two splitters and two switch JB and stripper (up to 2.5mm² T&E) but the jb only take 1mm/1.5mm². This is a wise investment not just a tool for a week and then gets...
  26. C

    Loop at switch - 2 gang switch

    Hi All, I am new to the site and have recently started doing more and more electrical work in my house, nothing too major, changing face plates, light fittings etc, however I have encountered an issue that I cannot sort out. I have a 2 gang light switch where it is looped in the switch. Nothing...
  27. Rocboni

    Closed loop Sensor monitoring

    Hello, How are closed loop sensors like the below and monitored integrated into a control system, isolation switches/switch amplifiers? These are typically used on explosion panels where when they blow off it snaps the cable or ceramic plate causing an open circuit. (I’m Prepared for the...
  28. C

    Refurb works In offices

    Just your thoughts on this one,doing a part refurb on existing offices,no initial verification or certs found anywhere. Premises rewired bout 1990,adding sockets here & there in each room. The DB is a Crabtree Tpn polestar,just finished some loop readings ,& not good,1.49 the highest,there is...
  29. Midwest

    Loop Impedance Testing - Strange fault code

    Being doing a domestic bathroom refurb', lighting, altering shower circuit (have a Megger 1730 MFT). History, property has no RCD protection, but as it was a Hager CU, had contemplating using RCBO's (TN-C-S supply). Before doing any work, I decided to clamp the meter tails, as the property has...
  30. soms

    Earth loop impedance measurement affected by dimmer switch

    Working on a job today which included a very simple new lighting circuit. The lighting circuit a very short run from a distribution board to a single switch position, which then supplies a single luminaire. The customer wanted a dimmer switch to control the fitting. To crack on and perform the...
  31. Gary Tollison

    loop impedance, temperature, cable factor....

    Hello I'm not sure if this is the correct forum area to post this in, apologies if it isn't... I've been working through some mock questions on-line, and found myself confused by this: The measured value of loop impedance for a circuit is 0.83ohm. If the temperature at the time of the test was...
  32. Gavin John Hyde

    External earth loop Ze with switched fuse before CU

    Got a job where im having to do the usual testing. I have never tested a set up where due to the tails needing to being so long to reach the consumer unit there has been a switched fuse, this is i believe a standard directive from the DNO the tails then terminate into swa and run from the...
  33. S

    TT Ze reading- loop high or loop no trip?

    When measuring Ze on a TT that's RCD protected which is more accurate? Getting 27.1 on high current but 563 on no trip.
  34. 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...
  35. J

    Ceiling rose wiring

    Hi. I've been trying to change an overhead light and run into some confusion regards the wiring and I wondered if someone could advise please. I've currently got over my confusion by doing a like for like swap of the pendant, wiring the new light into the old ceiling rose terminals. I would...
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