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  1. cgrodzinski

    Tolerance for temperature rise in cable sealing end

    What is the voltage of the circuit?
  2. cgrodzinski

    HV Cable Single Point Bonding within a substation

    Hi 7another4! Thanks for the addresses on behalf of all participants of this thread. However, the duct vs direct buried could be discussed. In the first post of this thread ahandle was connecting a transformer with switchgear. I would use rather cable bus than duct but he may have a different...
  3. cgrodzinski

    HV Cable Single Point Bonding within a substation

    Kiribanda, as you noticed we are talking about the induced current. A magnetic field is always present when current flows through a conductor no matter what material is made of. If an another closed circuit conductor is placed in this field an electrical current will be induced when the magnetic...
  4. cgrodzinski

    HV Cable Single Point Bonding within a substation

    It doesn't make any sense to me to build a duct with several conduits to run 3.3kV cables. The duct bank itself will cost many times more than the cables. In my opinion, for this purpose there are cable ducts that are designed by cable specialists that have available engineering calculation...
  5. cgrodzinski

    Circuit Breaker lugs temperature monitoring

    If the system is important the BJC advise is what you should use. It is dielectric and the information can be transfer over long distances 24/7. Off course all perks of other older type equipment are included. However, it doesn't come cheap but is very reliable in electrical field environment.
  6. cgrodzinski

    HV Cable Single Point Bonding within a substation

    I would suggest that you consult manufacturers of "cable bus". I do not know the details of your intended installation but installing them all together in one conduit does not seem to be a good idea to me. Note that the all cable metallic parts subject to mutual induction (no matter how long)...
  7. cgrodzinski

    AC vs DC Hipot Test

    inclebob, every voltage AC, DC, VLF (technically it is AC) ... that is applied to the insulation will have some detrimental effect on it. If the voltage is high enough to break the insulation ... this is the outcome of the test. The purpose of the "HI-POT" is to check if the cable insulation is...
  8. cgrodzinski

    cable calc

    Gentlemen, the thread started with the post asking for cable calculation not testing and we should come back to it. While calculation of the cable ampacity is not a new problem its modelling is IMHO the biggest obstacle as well as understanding the cable working conditions. The MV calculations...
  9. cgrodzinski

    Cable bending radius

    I do not have too much experience with pulling low voltage cables but there are three conditions that should be looked after during any pull. 1. maximum pulling tension 2. minimum bending radius (as the multiplication of the overall diameter not individual conductors) 3. maximum sidewall...
  10. cgrodzinski

    Cables in Trefoil

    dpc, it is something wrong with my math? Is this what you meant?: 510A > 2 x 380A or I misread your post?
  11. cgrodzinski

    Cables in Trefoil

    I know that it is difficult to install such conductor but it is not impossible. The bending radius is usually 15 x cable diameter. If 1000mm2 the cable diameter is ~41mm so the radius is say 700mm. Regarding ampacity - I would say in reverse: that the ampacity of a circuit does not double when...
  12. cgrodzinski

    Cables in Trefoil

    I think that using 1000mm2 per phase gets better current density than 3x400mm2 = 1200mm2 for the same load. In my opinion using multi-cables per phase circuit produce more copper than bigger conductors. It is easy to check by using IEC standard. I have seen 2000mm2 cables being installed.
  13. cgrodzinski

    AC vs DC Hipot Test

    Gentlemen, all "withstand" tests are of "kill or survive" type tests. They give very little (if any) information about any cable conditions. The discussion among cable engineers and scientists is ongoing for decades. Fortunately, with the development of power electronics we have a better chance...
  14. cgrodzinski

    Data of 35kV Cables buried for power collecting in Wind Farm of USA

    igg1966, the NA does not differ from other parts of the world. Current flows in the same direction so whatever you calculate in Spain is applicable behind the big puddle called Atlantic. The web pages given by others could be a great help as other European cable manufacturers. There are...
  15. cgrodzinski

    Cables in Trefoil

    Jareb, I do not know rationale behind the decision of using 400mm2 cables. I would rather use 1000mm2 single conductor per phase. If, however, you have to use 3 conductors per phase there is something called "cable duct". If your voltage is 600V (I assume based on cables you mentioned) the cable...
  16. cgrodzinski

    manhole grounding requirement

    a10jp, what voltage of the power cables we are talking about? Generally, if there is any metal part that is in the same compartment and it is not intended to be energized - it should be grounded. It means that if you have supporting structures for the cables in the pull-thru manhole they should...
  17. cgrodzinski

    Cable Ampacity Calculations

    To be on the same wavelength - I am talking all the time about concentric neutral wires - NOT cable conductor. I understand that you use "single end grounding" method - only at one end? Is this correct?? If it is, you do not have to worry about the cable concentric neutral (assuming that the...
  18. cgrodzinski

    Cable Ampacity Calculations

    RIA123, have you consider grounding the concentric neutral wires? If yes, let us know how. The EDSA program follows the rules of IEC60287 so it must use the circulating current if any. Thanks
  19. cgrodzinski

    3 Phase HV Cable Sheath Cross Bonding

    Sorry folks for "reheating" this a few months old thread. I was looking for information on the same subject and arrived here. Most of what was written here is right. However, the cross-bonding system does not eliminate the circulating current entirely if it is used on the arrangement shown above...
  20. cgrodzinski

    analogue outputs

    dawn2, Thanks. I made sure that they know about it.

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