fault current

  1. N

    Fault current on a 11'000 transformer

    Hi guys, haven't posted in a while. Working at a hospital now, we have 2 11KV transformers on site. We only run 1 at the time , the other is just used as a backup (close a bus coupler to bring it in). Being a nosy git, I asked about running both transformers at the same time. Obviously this...
  2. HappyHippyDad

    Regulation 434.5.2 Fault current!

    Cant quite get my head around how you use this reg? Lets say S =16 I = 657 k = 115 You have to work out t first of all so t = K2S2/I2 so t = 7.843409 (to 6dp) therfore K2S2 = 3385600 The reg says that we need to make sure that K2S2 is greater than the value of the let through energy...
  3. R

    fluorescent light fault current

    I was wondering how much, or if any fault current fluorescent light fittings produce, it's just that I have 16 to fit in one area and was wondering If protecting them all with one 30ma rcd and separate mcb's would cause nuisance tripping.
  4. W

    Fault current.

    Dear Forum, Can anyone explain in simple language what the difference is between P.F.C. and P.S.C.C. and how is each calculated? Thanks, Wayne:dizzy2:
  5. infinity

    Bs3036 fuses and high fault current

    I have recently carried out an EICR on an old building, one of the main DBs is an old Bs3036 board with 3 phases. When testing Ze i measured 0.06 and a PFC of 3.8ka giving a measured value of 7.6ka (as its 3 phase) Obviously the fault current is too high for the fuses, but can you take into...
  6. M

    Prospective fault current ?

    Can somebody please clear up for me what is prospective fault current? Am i right in thinking its the value of overcurrent you get through fault conditions like short circuits and live conductors and exposed conductive parts ? Thanks
  7. ringer

    Prospective Fault Current

    I was under the impression that PFC is the greater of either the PEFC or the PSSC. Now look at this article (endorsed by the NIC) on Voltimum.... Voltimum Q&A I am assuming that the guy's tester is indicating over-range on the PSSC measurement. Apart from the fact that the way it is written...
  8. G

    Prospective Fault Current

    Two questions here really Am i right in thinking that PFC is Prospective Fault Current or is it power factor corection? Second question is why is it important to know the Prospective Fault Current? Thanks
  9. S

    Prospective Earth Fault Current

    can anybody help me with this question? Why is Prospective Earth Fault Current important during the design stage of an electrical installation..
  10. spud1

    Prospective fault current in a TT installation

    Hi Chaps, When measuring and recording PFC at the origin in a domestic 230V TT system for say an EI cert or an EICR, do you record the PFC L-N instead of L-E as this is clearly going to be highest reading if say Ze is 65 ohms?
  11. D

    Confusion with prospective fault current test

    Hi guys, Been getting a bit of practice with my new Metrel MI3000. Most functions are fine, but I'm a little confused by the Z Loop impedance test. In the book, it shows the Line, Neutral and PE probes being connected to their respective terminals on the board. When I do this and press test...
  12. E

    Prospective Fault Current

    I recently fitted a dual RCD MK board in a house. Everything has tested out fine but I was a bit concerned about the following readings. Ze is 0.03 ohms and the PFC is 7.3 KA. The supply transformer is just over the yard wall. The breakers in the board are rated at the usual 6.0 KA. Do you...
  13. L

    Prospective Fault Current

    Hi Guys, We measured PSCC on a three phase dist board in a commercial establishment. This board is fed from a main switch board with a main 400Amp switchfuse with BS88-2 fuses rated at 88kA. Feeding a second 160Amp switchfuse with BS88-2 fuses protecting the cabling to the board we were...
  14. W

    Prospecctive Fault Current purpose....

    Hi Can someone explain the reason for testing the PFC and what it confirms? And what is the reson the value is doubled for 3-phase? Thanks
  15. M

    Prospective fault current

    Hi I'm looking for some advice and options. I have installed a new board a British general one the customer has bought. I also got the meter cut out upgraded with a main switch put in. At the main sw the pscc is 17.8, pefc is 6k Which seems funny to me cause tncs which I'm sure new cut outs...
  16. T

    Maximum tolerable fault current

    Just completing the testing of a transportable catering unit.(chip van). Within the NICEIC REPORT I must complete, a.MAXIMUM TOLERABLE FAULT CURRENT(is the same as PSCC)? b.MAXIMUM TOLERABLE UPSTREAM ELI.(is this the same as Zs)? If so how do I achieve these values when the Power...
  17. D

    Please Explain: Symmetrical fault current

    Im doing my 2391 course and it was quickly mentioned about symmetrical fault current when talking about PFC testing. It was just mentioned and not explained so can anyone explain what this means. My first thought is that 3 phases shorted together would cancel out and leave 0 volts?? But...
  18. B

    prospective fault current

    on electrical installation certificate at the top under supply characteristics it asks for (next to single phase) a prospective fault current in KA How do i measure this reading please? Thanks!
  19. S

    Through Fault Current

    I want to understand the concept for through faults in case of transformers. For example, there is an external fault on secondary side of a generator step up transformer, so when it is said that all through current will pass through the transformer, does it mean that current is now flowing in...
  20. B

    Prospective Fault Current

    Hi guys. I just got the results back for my AM2 and I passed everything except the PFC. I now need to go back and do the whole testing proceedure again which I am gutted about. When I tested the PFC, I don't think I had three leads from my tester, I seem to remember only seeing two leads...
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