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Recent content by shlim

  1. shlim

    Is damage to cable outer sheath/jacket detrimental to inner XLPE insulation?

    These cables have been operated for at least 30years old. The damage to the sheath was recently discovered. I do not have direct access to the cables or the historical electrical test results hence the difficulty to identify/establish the extent of damage especially to the XLPE insulation, if any.
  2. shlim

    Is damage to cable outer sheath/jacket detrimental to inner XLPE insulation?

    Thank you 7anoter4 for your opinion and sketch, I will try to check whether there is any damage to the insulation at those locations.
  3. shlim

    Is damage to cable outer sheath/jacket detrimental to inner XLPE insulation?

    Hi, I have an installation of 132kV XLPE single core copper conductor, with copper armouring (attached photo). These cables were in trefoil formation, tied/fasten with polymer rope (likely nylon). At some of these ties, the rope had "eaten" into the outer sheath, where I could see the...
  4. shlim

    CO2 cylinder valve - function of the "push button/cap"

    Hi @stookeyfpe, your comments are much appreciated. Thank you for the clarification regarding the function of the cap. I was wondering whether it was a safety cap that prevented activation during installation; and it should be removed when the system is in operational mode (so that it could be...
  5. shlim

    CO2 cylinder valve - function of the "push button/cap"

    Dear all, I hope this is the relevant site to post my question. Please re-direct me if there is a better channel in this forum. I came across a CO2 fire suppression system, which had been claimed to have been activated after a small fire inside an electrical room. 1. The pressure gauge for...
  6. shlim

    Can coal dust causes arc-flash?

    I have actually forgotten to check on this thread because I did not receive any email notification. I agree that the best way would be the improvement of the HVAC system for the electrical room. Thank you all for the inputs.
  7. shlim

    Can coal dust causes arc-flash?

    Hi, I hope this is the right place to post this question. I have an arc-flash incident, with known presence of coal dust accumulation and high humidity environment in the electrical room. From my current readings, I note that some coal type are conductive and some are not. I am looking for...
  8. shlim

    Transformer bushing power factor

    Thank you prc. The one in question is OIP type bushing, so yes, it is in very bad condition. I think I am confused/mistaken with the pf for power system where the unity value is 1.
  9. shlim

    Transformer bushing power factor

    If I have a bushing that has 1.xx% pf, for two consecutive years, the measurement is not necessarily wrong? Instead it just showed that the bushing is in a very "bad" condition?
  10. shlim

    Transformer bushing power factor

    Hi all, is it possible to have bushing power factor test result to be more than 1 (one). Is this measurement different from the typical power factor for power system (unity = 1.0)?
  11. shlim

    Wiring for Lighting

    IRstuff, for example the highest recorded is 30.8 degreeC vs the colder region of about 27.6 degreeC, at the same light switch. itsmoked, thank you for your detailed explanations on how in-rush current and heating (and increased contact resistance) caused cyclic deterioration to the light...
  12. shlim

    Wiring for Lighting

    IRstuff, our team did. There was about 2-3 degree C difference between the normal switches and the faulty one (one wall-mounted light switch has up to 5 switches).
  13. shlim

    Wiring for Lighting

    HCBFlash, I am not familiar about the specifications for W/sqft for lightings purposes, but your point is taken. We typically used 10Amp MCB for lighting circuit. Nevertheless, we managed to detect more hotspots at other similar light switch installations using infrared thermo-camera. The...
  14. shlim

    Improvement of PVC materials for cable over the years

    Hi there, I am looking for any references comparing the quality of PVC-insulated cable made (say) 40-45 years ago vs today. Is there any improvement(s) in terms of materials composition, or the quality in general, for PVC-insulated cable, made 45 years ago versus the same type of cable made...
  15. shlim

    Wiring for Lighting

    Hi, JG2828 and waross. I am from Malaysia, and we follow British or generally IEC standards. I am looking for any reference to my technician's comments, just to confirm whether it is a written guideline, or just a norm that people follow in this part of the world. I would certainly agree with...
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