1. J

    UK Zs readings unusually high on new installation, what is the best option to lower them?

    I've just finished an installation on a large outhouse around 50 meters from the main property, but I'm having issues with unusually high Zs readings within the new installation.. The nature of the installation is a TNCS system with 25mm tails & 16mm cpc Henley blocked from the main supply to a...
  2. alexander jackson

    UK Zs Readings seem to be a bit low.

    Gents. I did some earth loop tests on Rolec power pedestals (2x 16 amp outlets) that are harbour side, looped in and out from one another. Three months ago I got Zs readings from about 1.2 ohms to 0.50 ohms. This time round the readings are all less than 0.01 ohm. Megger MFT meter. The RCD in...
  3. R

    R1,R2,Rn versus r1,r2,rn continuity readings on EICR.

    Looking at the EICR form. GENERIC SCHEDULE OF TEST RESULTS Looking for clarification on R1,R2,Rn versus r1,r2,rn continuity values. I have reached the some conclusions. Do r1,r2 and rn only apply to ring circuits and R1,R2 and Rn (not on form) to radial? It just looks like that might be the...
  4. V

    Different Ze readings

    Hi, I've had an unusual result from taking a Ze at a clients house and wondered what everyones take on it would be: The property is TN-C-S A Ze reading from a disconnected Earth to Line gave a reading of 0.45 ohms A Ze reading from the Line and Neutral gave a reading of 0.33 ohms A TN-C-S...
  5. B

    Current transformer metering producing implausible readings

    Edited - please read right to the end! Grateful for any advice regarding CT metering which seems to be generating inaccurate/implausible readings. Our charity has a commercial building with 3-phase connection into a busbar chamber at one end - let’s call us ABC. The rest of the chamber...
  6. banny07

    UK I am getting very high zs readings

    Hi Guys. When measuring zs I get very high reading. Ze is 0.3 (tns), zdb is 0.21. r1 and rn are is 0.42. r2 is 0.72 , r1+ r2 is 0.29 . when I test zs it 8.26 ohm new to testing. I even buypassed rcbo but it stays same. Do you think my mft if faulty? Any thoughts guys? I am new to testing.
  7. T

    Battery/solar/inverter system gives inaccurate power readings

    Hi, I have purchased a battery/inverter/solar system for my home. I also have a smart meter, and an app which links into my smart meter to get the power data from the smart meter. The battery/solar/inverter system also tells me how much energy I am using. However, its readings are not accurate...
  8. P

    Low IR test readings on lighting and RFC.

    Hi,guys went to do an EICR and when doing IR test I got L-E ON RFC like 0.02 MOHM and two lighting circuits L-E AND L-N the results were like 0,14 and 0,15 MOHM.It is old wiring where all the cables live and neutrals are black put in the walls in steel conduit.My question is is it possible that...
  9. S

    Voltage readings

    Came across a weird one today… Four single black stranded 12gaTHHN running through 1/2” conduit about 40’ to first outlet box and 70’ to the last, on a branch from main panel. One 20A breaker and one 30A breaker. The homeowner asked to eliminate existing locations and reroute, no problem. I...
  10. Dartlec

    Low Zs readings on MFT1771

    My main tester is a Megger MFT1711, which I bought second hand but came with a calibration certificate. Rather than annual calibration, I have a calcard and check it monthly(ish) and keep records, which my NICEIC assessor has been quite happy with for years... I have an original MFT1552 which...
  11. D

    Ring circuit readings

    Hi all I am about 2 years retired after being NICEIC registered for over 20 years. An old customer just a little concerned about an EICR just been done on her property by someone else now with lots of N/A everywhere main one being no end to end readings (R1R2) entered for the ring circuits I...
  12. M

    Does this look like an earthing issue? Meter readings attached

    Hi folks. I am regularly experiencing tingling shocks from my laptop and kettle. Both of these things are plugged into something with a ground plug. I decided to measure the neutral to earth voltage, at least for the nodes I can reach at my plug. I see significant AC voltages measured between...
  13. P

    Insulation readings

    Hi, I’m confused. I recently carried out insulation resistance test on a 3 phase board I had some weird readings. I removed all vulnerable bits of kit and tested the dead side of the incomer all readings where good a part from L2 which had a low reading of 2.8M ohms. This was much lower than...
  14. F


    carrying out an eicr on a building recently we found the external ze reading to be extremely low ie 0.02ohms. so by measurement and testing are fault current read 20ka. now most of the mcbs rcbos ets have an icn of 10kohms. this poses a problem as obvisoluy the mcbs etc would self destruct under...
  15. C

    Martindale et4000 high readings, calibration?

    Hi all I've just purchased the martindale tester second hand from ebay. In comparison with my metrel mi3002 and ht macrotouch, it is giving almost twice the readings. In my mind, this is a faulty unit, as calibrating will only check the tolerance, and if the readings are this far out, it...
  16. B

    What are the possible causes of low IR readings at 500VDC?

    Kitchen RFC 2.5 T+E - IR=>200MOhms at 250VDC L&N to E but 0.34MOhms at 500VDC L&N to E. I suspect damp/corrosion in sockets, what do you reckon? All socket switches opened including SFCU to cooker hood, F/F, D/W and W/M.
  17. 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...
  18. S

    Question about Power use monitors-inconsistent readings

    Have any of you used appliance power use monitors to measure how much power a device is using? I recently bought one that plugs into a wall socket and then you plug the appliance into the device and it tells you the voltage, amp draw, wattage and Kwh the appliance uses. If I plug a fan heater...
  19. M

    How do i calculate missing resistance readings in a parallel circuit using R1 and Rt

    Hi I am a current student studying to become an electrician and a question has thrown me. I'm wondering if someone could help, there is a question on one of my home work books. "complete the following table assuming the resistors are connected in parallel?" the example I will give is R1 is 120...
  20. B

    Earth readings

    TT system Ze is 17.5 ohms but when connected it is 0.60 ohms? Have one outgoing 95mm SWA and one 240mm SWA earthed either end and individual rods? Thanks