impedance | Page 5

impedance

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  1. F

    Fluke 1563 - Loop Impedance Test problem

    Does anyone have a problem with their Fluke 156X testers when doing Loop Impedance Testing ? Most of the earth systems I come across are TT and my meter will on the odd occasion show >2000 ohms and then on a repeated try I get the correct answer. I think the problem gets worst when the L-N...
  2. A

    Cable selection, calculating earth fault loop impedance

    Hi guys, struggling to work this question out and don't seem to be getting a correct answer no matter what cable conductor size i use. Q. A 230V 14kW domestic electrical cooker, installed in a house is to be supplied by a 15m run of PVC insulated and sheathed cable, clipped to a surface. The...
  3. G

    socket testers earth loop impedance indicators

    can anybody tell me if these are worth using as a fault finding tool they claim lots on them,anybody used them?:icon3:
  4. R

    why a low earth fault loop impedance

    hi guys, Just wanted some help with some course work for college. Any help is greatly apprecitaed. Why should a low value earth fault impedance should be achieved for all circuts? thanks
  5. M

    Earth Loop Impedance Test and problem with power supply

    Hi, Our main fuse from the power distributor blew and Western Power attended and replaced. During this visit they established that their was a problem with reverse polarity and that when the RCD was installed the tails in the grey twin cable were connected red-black in the top of the consumer...
  6. S

    The Value of External Impedance (Ze)

    Hi everybody can anybody help please all answers will be taken into account for proccessing thanks... can you please explain to the Newbie (ME) why is the value of external impedance (Ze) required during the design stage of an installation.. THANKS.....
  7. T

    Line to earth fault but MCBs will not trip..Why?

    I was called to a single phase installation in a pub as the staff were receiving shocks when touching equipment such as fridges water pipes etc. I located a damaged cable where line and PE conductors were touching and causing 240 volts on the entire earthing system at the installation. In other...
  8. J

    PFC Testing

    Hi all. Just a question which seems to get me a bit confused about PFC testing. I understand that the value of PFC you put on a EIC or any other form is the highest value of either the PSCC or the PEFC. Now when you get the reading on your meter (which is sometimes displayed with the Zs value)...
  9. L

    Impedance of short circuit path??

    Hi, Probably fairly simple but I'm learning. Have an example for working out fault current/disconnection times. "A 10mm PVC sheathed MI copper cable is short circuited when connected to a 400V supply. The impedance of the short circuit path is 0.1 ohms. Calculate the permissable disconnection...
  10. B

    Calculate Earth Loop Impedance - Cable >35mm2 Impedance Data

    Hi all, Where do I get phase (Z1) and earth (Z2) conductor impedances to calculate earth fault loop impedance? I have seen (R1 + R2) tables which give combinations for cable sizes up to 35 mm2. What about cables > 35 mm2? Can I use voltage drop tables (for phase conductors) from Appendix 4 in...
  11. S

    RCD Upstream BG board HIGH LOOP impedance

    A domestic customer has MK dual RCD board #1 and another BG dual RCD board #2 in loft. On testing, a couple of circuits (32a & 16a radials) on board #2 had high Earth fault loop impedance ( over 3 ohms for a socket radial). I know that the BG board (in the loft conversion) does not really need...
  12. E

    ZS on final sub circuit

    Lads Have measured R1 + R2 and get a total of .45 ohms, when I test the ring with my tester I get 2.1ohms, the unit was calibrated last week, any ideas?
  13. T

    Earth fault loop impedance readings through a UPS supply

    Does anyone have any experience in recording values of EFLI on circuits fed through a DB supplied via a UPS please? The meter shows the above scale arrow. I understand that there will be no reference to the external earth due to the inverter inside the UPS but what will happen to the UPS...
  14. J

    Measuring earth loop imopedance Ze using FLUKE meter - settings??

    Guys (n' girls of course) I have just started using a 1653B FLUKE and when testing earth loop impedance Ze (ie. impedance of supply - tested at supply origin), I presume I use the 'LOOP IMPEDANCE' setting (line to protective Earth L-PE) using the Z1 Hi current setting, and NOT the 'Earth...
  15. H

    sMaximum earth loop impedance for TN systems, and TT system

    I am finding this quite a complicated subject, and I would really welcome your thoughts on this subject. If I could start with a TT system, according to regs, 411.5.3 states that when using an RCD for fault protection purposes, then the following has to be applied. RaxIn<=50 This means that...
  16. 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...
  17. 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?
  18. C

    L-E fault always trips mcb?

    Hi, i am studying my 3rd yr 2330 and soon to do my fault finding, and was wondering if you had a L-E fault if the mcb would always trip or if just the rcd would trip sometimes on a 17th edition board?
  19. 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 (...
  20. W

    impedance

    hi guys, what are the main reasons for a high impedance readings and what the best way to lower your impedance

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