resistance | Page 9

resistance

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  1. N

    Street lighting fault

    I'm going round in circles with this fault. We have 12 street lighting lamp posts at our factory, 150W son lamps in each. They were on a 20A MCB and yesterday started tripping. They are basically wired from a 20A MCB (2.5mm), through a relay, out of the relay in 6mm armoured and then outside...
  2. P

    Testing IEC Extensions

    Hi all and thank you for letting me join the forum !! I do a bit of Pat testing at my work and have been asked to test some of the leads that attach to the IEC leads with the plug on(I.e. to make them longer). As these haven't got their own plugs do they have to be tested as surely they are only...
  3. L

    Earthing resistance

    Hello wondered if anyone can help. I have an exam in a couple of weeks and need to know this. Googled it but can really find an answer. The question is. What is the maximum allowable value of earthing resistance of a conductor by your local standards. Thanks in advance
  4. M

    indicators faulty...

    Hi guys this is probably a bit basic for what I've seen around here but I was hoping someone could help... I have an old Hyundai Excel '95 and the front and side left indicators are out and rapid signalling on the dash board and the back left light is rapid signalling. The first thing I tried...
  5. M

    High resistance on ring circuit

    I was to asked to add a spur on a ring circuit. I done a continuity test to make sure i had a ring the N-N was 0.46 CPC-CPC was 1.08, But my L-L was 2.4, i went round every socket looking for a loose conection. Tightened up a few loose sockets and the reading came down to 1.9 i coudlnt find any...
  6. S

    9KW Shower on 4mm cable

    Hi, While carrying out a periodic inspection I came across a 9kw shower on 4mm cable, 40A type B ocpd, 30ma rcd. I have given a code 3, for the following reasons; 1. No sign of thermal damage at any termination. 2. Shower cannot overload as fixed load. 3. Short Circuit & Earth loop impedance...
  7. D

    Confused...max electrode resistance with RCD?

    Sorry guys. Probably sick of me by now got exam tmrw and checked old posts and books but still bit confused with allowable max electrode values. Does max 200 ohms still apply if RCD is inplace? If so why do we even have a max resistance for rcd disconnection if these values are so much more than...
  8. N

    Insulation resistance testing

    Sorry, I'm almost ashamed to ask this question. Cooker switch with red indicator bulb (1)Please tell me what exactly what I do to not get moody readings on a IR test. ? (2) Are there any other tests that it would cause me a problem. ? Tried to search couldn't find an answer that clicked with me
  9. D

    continuity test on steel trunking?

    Hi guys Just a quick one. Doing 2394/5 going through mock paper can't find answer anywhere. How would a continuity test on length of steel trunking be carried out? Any help appreciated
  10. E

    Minor Works, Insulation Resistance Testing, and 612.3.3

    Hi all I couldn't find any previous posts on this topic specifically so looking for some advice. I am adding an external security light for a customer. I am extending the existing downstairs lighting circuit. Normally when testing Insulation Resistance I would test between L-N, L-E, N-E...
  11. J

    2394 practice question

    How would one figure out the following question? The resistance of a 2.5mm copper cable is given as 7.41M Ohm per metre at 20 celcius and that of a 1.5mm copper cable is given as 12.1M Ohm per metre. A circuit wired with 25m of 2.5/1.5 twin with cpc sheathed cable would have an expected R1+R2...
  12. B

    Ring end to end results not text book for cu change.. do we need to ensure 1.67 times

    Hi, Cu change pre tests (TT) indicate non text book results: r1=072, rn=0.92, r2=1.58 another ring: r1=0.67 n=0.67 r2=1.60 As can be seen the r2 values are more than 1.67 times r1 or rn possibly due to loose connections. Are we responsible to try and bring these values in line for a cu...
  13. C

    RCD question

    Can anyone tell me what thelowest insulation resistance for a low voltage circuit tripping time on a rcd or where i could find this on the regs
  14. M

    low insulation resistance on 35mm lsoh cable

    Looking for some advice.currently doing a install of a block of flats fed from a bemco using 35mm aluminium split concentric cable low smoke.tested the cables and getin low readings of around 40 mega ohms on all between neutral and earth.1 cable is only 3 metres long.any one ideas why there so low
  15. S

    Checking loop tester readings from a sample socket.

    After calibration of my loop tester,I am considering using a socket in the house for future calibration checks and to connect various low resistances in series with earth via a rotary switch to give a range of readings,and if so what value of resistors?Thanks for any advice...
  16. S

    Insulation Resistance

    So i have db1 in 1 block of flats for communial lights etc, feeding db2 via a swa feed underground. Ir at db1 to test every circuit and submains 0.01Mohms. (N+L together to earth) Switch db2 off. All clear. Db2 also all clear when testing ir when investigating further. Any suggestions??
  17. R

    Ring main IR question from todays EICR

    Hi All, While carrying out a commercial EICR today, I was doing IR testing on one of the ring mains an was getting 0.00M ohms between L/N - and the earth bar at 250V & 500V (cant distinguish what 2 earth wires belongs to the other 4 cores) I have continuity on both L & N legs which are...
  18. HappyHippyDad

    What could cause my voltage to drop to 28V??

    Evening all.. I have just tested a cable that I had put in place myself for a smoke detector and I am only getting 28V L-N. I am getting 240V L-E. When I first put it in it tested 240V. Since then the builder has been in and put the ceiling up, I'm not saying this is the cause but this is the...
  19. J

    "Electrical leak trace resistance" and "Anti-squelch interference capacitor"

    Hello, I am a translator translating a standards document from Chinese. There are electricity-related sections in this document which contain a couple of terms for which I have not found an adequate translation. These two terms translate literally as "electrical leak trace resistance" and...
  20. B

    Caravan suppły RCBO

    Hi I haven't posted for a while but I'm having some issues with a caravan park I have recently carried out some work on and washoping somebody may be able to shed some light on the issue. The problem is burnt out neutrals on out going side of RCBO, we have replaced 137 caravan suppły points...

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