resistance | Page 6

resistance

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  1. Lee Gold

    Calculate the resistance of a copper (annealed)

    what's the difference annealed? Calculate the resistance of a copper (annealed) conductor 35m long that has a C.S.A of 2.5mm2?
  2. Strima

    CSA and resistance of 20 & 25mm Steel Conduit

    Can anyone point me in the right direction to find out the CSA and resistance of 20 & 25mm steel conduit? It's for part of my 2396 project where I'm using the conduit as CPC, I'm happy enough with the calculations I just need some numbers to work with. I've tried various manufacturers websites...
  3. Lee Gold

    Working out resistivity R=pL/A

    Examples Please
  4. 1

    Insulation resistance test

    Hi all on a eicr insulation resistance test between live conductors to earth gn3 says join l & n and test to earth is there any difference between that and testing phase to earth then neutral to earth? As you guys know some boards are a right mess and not in order to locate which belongs to which
  5. J

    Resistance Level 2 - HELP NEEDED!!

    hey, I am currently completing City & Guilds level 2 and stumbled across the below questions and scratching my head... 1. Electric Fire element has a length of 10m, a cross section area of 0.5mm2 and resistance of 50 ohms - calculate resistivity of material used. Thanks
  6. M

    No resistance Circuits

    Hi guys, How do you use ohms law on a circuit with 0 resistance? So, assume there is 10Amps and 0 Ohms on a circuit, how would you find the voltage? (E=IR?) Also assume you have a circuit with no resistance on it, where would be considered the return path? Like the potential difference I mean...
  7. P

    Cables with thermosetting insulation (XLPE cables)

    I understand that XLPE cables operate at a maximum temperature of 90c compared with 70c for PVC insulation. What I don't understand is why the increased temperature permits a reduction in conductor size if XLPE insulated cables are used in preference to cables having PVC insulation. If the...
  8. M

    Grounding Question

    Hi guys, I'm trying to better understand how grounding works. I got the basic idea of it, but still have a lot of questions about it. K, so from my understanding, if you touch the neutral bar on a service panel you will not get shocked (because it is grounded). But why do you get shocked if you...
  9. M

    Resistance per meter of armour

    I know it's late and the lap dances are still open , so i will wait till tomorrow for any replies . Does anyone have resistance per meter tables for steel armour 90degree thermosetting ,can't find it anywhere . Ta
  10. D

    Diode advice

    I currently have an intermittent issue with a disabled alarm system. The pullcord has a fault monitor connected across it in the form of a resistor and diode in series which I suspect is the culprit. The diode only reads continuity one way as expected but the resistance through it the correct...
  11. D

    VIR or PVI

    Hello Guys This is a right noob question but its really been bugging me. ok so i have a pc which is 500watt (labelled) but runs on 110v and 230v. V/ I X R : 230/38 = 6.05A 110/38 = 3.10A But using the formula P VI i get the following i wanna work our i so p/v 500/230 = 2.17 500/110 = 4.54...
  12. S

    500v Insulation Resistance Test ok?

    Hi all, still training so please forgive my very simple question. Why is it ok to test an appliance at 500vdc when PAT testing but great care should be taken to remove all equipment when IR verifying a new circuit installation? Is it simply just because connected equipment will make a nonsense...
  13. D

    SMA 4000TL 'Insulation resistance' error

    I've recently found the green light flashing and the red light on on our SMA 4000TL with the message 'Insulation resistance, check generator' on the display. Checking the ERROROB2.CSV files I can see that this isn't the first time it has errored in this way, it has happened on odd occasions for...
  14. T

    Newly Qualified to domestic level

    Hi am Tony newly qualified Domestic installer just thought i would say hello really.
  15. S

    Worst tested cable I ever found doing a EICR

    Last year at night I was carrying out Electrical Inspection and Testing and Found the 300mm 4 core SWA sub main cable to a chapel was recording 0.09 ohms on carrying out high insulation resistance testing between phases. 25 thousand pounds later its rectified. Would love to hear other people's...
  16. LeeH

    Resistance of a transformer windings.

    Does any of you clever chaps know what the resistance of a 5kVA transformer should be? It's a 240-110 CTE. I have a resistance of 0.16 Ohms (1400A) If I recall what little transformer theory I covered years ago the impedance will increase when energised but how much I have no idea...
  17. P

    Low insulation resistance reading

    i've recently installed a new Consumer unit at home and will be using it as my first niceic assessment. I'm getting an insulation resistance reading of 1.7 on a lighting circuit in the osg it says minimum reading of 1 is this going to be ok? I've discovered what section of the circuit is giving...
  18. N

    Insulation Resistance test with 12v transformers

    I am installing a C/U and the kitchen has some old Down lights installed with 10 x 12 volt transformers connected. I know I could disconnect all the transformers but I don't plan to do that as it will be a real pain due to how the plasterboard has been bodged. Some opinions suggest the IR...
  19. T

    Insulation Resistance Testing

    Evening chaps, In the process of taking my 2394/2395 testing course and just trying to fully get my head around insulation resistance testing predominantly in occupied domestic property's where it isn't possible to dissconnect all loads from the circuit. I am aware of the need to link out the...
  20. Jake Wesley

    Calculating power dissipated in a circuit HELP!!

    Hi guys. I have been looking on the website 'swindon massive' (very useful for anyone studying at college) and one of the questions in the mock exam for principles is; "An inductive load with 10 ohms inductive reactance is connected to a 100v 50 Hz AC supply. Calculate the power dissipated in...

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