resistance | Page 7

resistance

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  1. J

    Earth rod and bonding

    I've just done an EICR on an install earthed TT . The Ze on the rod was high 245 ohms , which in theory is fine as it is less than 1667 and the equation Ra X 0.03 > 50v is satisfied . When the gas and water bonds are reconnected the Ze drops down to 4.4 ohms , Do I put another rod in ? The...
  2. L

    Pat job questions

    Hi all got asked to do a pat job for client I under stand what I'm looking for check plug,fuse ,Lead,apliance for damage use pat machine we have this metro pat yellow box with three test buttons earth bond with a fuse selection and clamp I think pick half of rated fuse , insulation...
  3. D

    How does ring final circuit work

    Hello all I used to believe that the power of circuit is running from live to neutral,then go back to the distributor.But when I see ring final circuit,I get confused...I know the power goes from both side of live cable,then it goes back to the circuit breaker? Sorry about my poor...
  4. L

    Soil resistivity

    Hi, How can I change earth resistance (R) value into soil resistivity (Rho)? Is this formula correct, ⍴ (Rho) = 2πAR (A = Distance between pegs, R = Earth resistance). Regards, L.
  5. K

    armature resistance formula..help!

    please help guys i'm kinda stuck on this one, any help appresicated. A dc self-exited shunt generator has a field resistance of 160Ω. the generated emf is 420v and it supplies a load of 55kw calculate the armature resistance when the generator terminal voltage is 408v. thanks in advance kiwi
  6. D

    Hot Wire Cutter

    Hi all, I'm an architecture student and would be extremely grateful for some advice with a tool/machine that im making. Basically i'm creating a large hot wire cutter and need to pass enough power through to heat a 1.6mm, (or 2mm gauge) 1m long nichrome wire to a temperature suitable for...
  7. buzzlightyear

    micc on rcbo

    micc on rcbo will not set
  8. J

    Insulation resistance testing Lighting circuit

    Hi everyone. I'm looking for advise on how to test IR on commercial lighting. There's so many lights on 1 circuit , do I have to take out all the lamps in all the lights to perform the test or can I simply test between LN -E ? Even though I have spent lots of time testing domestic installs and...
  9. gazdkw82

    Missing resistors

    for some reason I'm struggling with resistors more than anything else in the electrical science (202/203) course material. I have a table with 6 examples, each having 3 resistors in parallel and a total resistance. Problem is a lot of the figures are missing and the question asks to find the...
  10. gazdkw82

    Parallel resistors

    I'm getting conflicting information regarding parallel resistors. I originally thought the below was how to calculate total parallel resistance 1. Rt= 1/R1+1/R2+1/R3 2. 1/Rt However in my pre exam workbook it says to 1. Calculate Rt as 1. above 2. Find the lowest common denominator 3...
  11. Karin

    resistance testing

    afternoon all, been reading up on testing and just wondering about the different types of testers and how they work.. insulation resistance - creates a potential difference across two conductors and measures leakage current to calculate resistance in MegOhms? low resistance ohmmeter - i've...
  12. C

    Fault Current Distribution

    Hello All, 1.Star connected earthed neutral Source to Star connected earthed neutral load? Say if a L-G fault occurs between the source and load, How does the fault current gets distributed? To the source side neutral or load side neutral? 2.Star- Star Transformer. Neutral earthed on both the...
  13. B

    Insulation resistance

    Is this right anyone? So basically I'm gonna test the whole consumer unit with an insulation resistance test rather than every circuit would you do basically I need to show my college and I've only been testing since last week and need to show an insulation resistance test of the whole board and...
  14. B

    Insulation resistance test help

    Hi I want to test the whole board at once with an insulation test so turn off main isolator and breakers turn tester to 500v? And is the best thing to do, the incoming tails L+N put in a link between them and connect your probes to the link and other to earth also can you still operate light...
  15. Pete999

    Resistance explained

    Well I never knew that
  16. D

    Insulation Resistance - Head Scratcher

    Hi folks, Was sent out to a job today to add in a hot water pump underneath a kitchen sink in a kitchen that had recently been done up. Took with me just a socket thinking that the electrician doing the kitchen work would have RCD'd it - but no. The woman had her own joiner do the work so I'm...
  17. Sintra

    Earth Resistance Testing

    Sintra submitted a new resource: Earth Resistance Testing - Earth Resistance Testing Read more about this resource...
  18. Sintra

    A Guide To Low Resistance Testing

    Sintra submitted a new resource: Low Resistance Testing - Low Resistance Testing Read more about this resource...
  19. sparky1508

    Insulation resistance problem

    Hi all, I have done an insulation resistance test on a ring final circuit today and when I do L - N I'm getting 0.01Mohm. Checked all sockets for loose connections but found nothing. I plan on splitting the ring tomorrow and testing each individual length from socket to socket. It's gonna be a...
  20. F

    Insulation resistance test on a db supplied via a time clock

    Hi guys new to this website just a quick question as it has been a while I have a small 6 way distribution board this only becomes live via a time clock supply wired into it I'm going to be testing this board with a IR dead test on each circuit just to make sure according to guidance note 3 & on...

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