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  1. SparkyLarks

    Insulated Busbars - Pros and Cons

    Thanks for the views. It does tend to confirm my own feelings. It offers a layer of protection, and given the facility is an alumina plant, The risk of tracking due to alumina dust is a reasonable risk. The plant is 30 years old and some boards have insulted busbars some do not. There has...
  2. SparkyLarks

    Insulated Busbars - Pros and Cons

    I'm ordering new 400V MCC's at the moment and was planning to go with Air insulated and supplier is pushing Insulated busbars. Basicialy just a plastic cover on the busbar. I'm of the view if sufficient spacing in used in the construction then the insulation does not offer much extra...
  3. SparkyLarks

    Resistance of an earth mat

    I am planing to install a buried copper lattice tape earth mat. 900mm x 900xx mesh of copper tapes 3mm x 25mm. I have performed calculations for substation earthing grids but cannot find the formulae for calculating the resistance. Help would be greatly appreciated
  4. SparkyLarks

    Earthing of Pipe supports

    7another4, You are correct, i intended to say"the pipe is not rigidly fixed to the pipe support" The Pipe will be fixed to the main piperack, The main piperack will be connected to the main burried earth using exothermic fusing. There are other pipe supports, which are individual vertical...
  5. SparkyLarks

    Earthing of Pipe supports

    I am working in an industrial plant, installing a new gas boiler. At a number of locations we will install small vertical pipe supports, there pipe supports will be isolated and only connected to the Pipes. the pipes ( Steam, air, Water ,Gas) will all be earthed as will the main Piperack...
  6. SparkyLarks

    4 pole fused disconnect (for Europe) make any sense?

    Have a look and EN60204 As far as I recall disconnection of the neutral is mandatory in France and Norway for a TN-S system. If you have a PEN conductor you do not want to disconnect the neurtal as it is also your protective conductor Often manufacturers install a 4 Pole Disconnect and then...
  7. SparkyLarks

    Welded Contact on a Star Delta

    why am I using Star Delta? I'm not.I would use a VFD personally but I am reviewing a design. They key question at hand is does the use of the K1,K2,K3( line Star and Delta) contactors, mwwt the requirements of EN ISO 13849-1. Typically Machinery builders will take the cheapest approach. As this...
  8. SparkyLarks

    Welded Contact on a Star Delta

    With a 3-phase star Delta motor , with three contactors. Does anybody know what will happen if one of the contactors welds shut. Essentially there will be a voltage supplied to one side of the windings. I am having a discussion whether the contactors on both sides of the winding is sufficent...
  9. SparkyLarks

    EU wiring question.

    typical EU residential locations have a single 230V P-N supply Larger Commercial buildings will have a a 3Phase 4 wire 400V connection. Though their phases will often be split at the main board and only have single phase sockets available throughout the building. Very few commercial locations...
  10. SparkyLarks

    CE Marking of Skid Frame as per Machinery Directive

    The skid frame is unlikely to need to be CE marked by itself but the complete skid is If there are moving parts driven by something other than manual effort then it is a machine and must be CE marked to the Machinery Directive. If you look at the machinery directive, an assembly of machine...
  11. SparkyLarks

    13857:2008 Safety Distances - persons of 3 years of age and above

    Are the edges likely to cause an injury. Why can the sharp edges not be removed. I I was ordering a perforated sheet I would specify that any burrs or sharp edges are to be removed.
  12. SparkyLarks

    neutral cable cross section?

    Are you familiar's with Kirchoff's Current Law. If not you should google it and read up. Basically if you have a single phase system the current flowing into a device, in the phase conductor , will be equal to the current flowing out on the Neutral For a balanced three phase system , we...
  13. SparkyLarks

    Transmission conductor midspan phase - phase clearance

    I think quite a few Californian Condors got cooked with their larfe wingspan. GO-95 The california Overheal line rules http://docs.cpuc.ca.gov/published/Graphics/52593.PDF is a very good reference
  14. SparkyLarks

    DOL motors & Thermistors

    I have a motor 4kW, DOL Start, with a Telemechanique GV2ME14 Motor Circuit Breaker. The motor an ATEX rated Motor and is installed in ATEX Zone 2 area. The motor manual is not clear on whether the Thermistor has to be wired if the motor is not fed from an inverter. I have emailed the...
  15. SparkyLarks

    unbalance in cable

    There are two possibilites 1) The current in the cables are the same and there is a CT issue 2) The current in the cables is different and the CT is working ok. A few questions 1) Is a similar unbalance seen in the S&T Phase 2) Is there a neutral on the system 3) What cables are installed 4)...
  16. SparkyLarks

    When to Megger Motors

    I work for a company that makes a small number of machines, and does work CE Marking third party machines. EN60204-1 says that you may need to perform Insulation Resistance tests but gives no guidance on when you may need to perform them. I'm trying to develop a few guidelines on when we should...
  17. SparkyLarks

    EMC pre-compliance testing

    From a European point of view I would say the Automotive EMC Directive ,2004/104/EC or the EMC directive 2004/108/EC must be complied with. As far as I can see if the Drive system is considered an Electronic sub assembly, and I would think it is then 104 is the guy. But I'm not familiar with...
  18. SparkyLarks

    AC CABLE SIZING

    If you are approving the use of the cable. You should be able to do this calculation yourself. Or you need someone to review it, peer, supervisor, or outside consltant. You also need to look at the protection for the circuit to ensure that it is suitable first. The cable size is then based on...
  19. SparkyLarks

    Transfomer vector group

    Specifing your vector group is important. It generally tells you how the windings of yout transformer are connected. Do you want a Delta,Wye, Zigzag or independant winding for the primary and secondary side of your transformer? the second question is what phase angle do you want between the...
  20. SparkyLarks

    Cam box suppliers

    ajack1 I tried Radionics, they have proximity switches but no Cam Boxes. Dbaird I will look at Gemco, I need the cambox for the safety circuit so I'm not sure if a Cam box from the US will beet the European requirements, but they do look to be the best option Thanks

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