Maximum zs

Discussion in 'Electrics UK' started by sparky23, 26 Mar 2008.

  1. sparky23

    sparky23

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    Hi eveyone just wondered if anyone knows of a site where i can get max zs for test sheets i have amtech software for my laptop but some max zs are not on there. Thanks for any info
     
  2. securespark

    securespark

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    You working to adjusted figures or not?
     
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  4. Spark123

    Spark123

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    What for, MCBs/Fuses?
    The max figures are in BS7671, if you are going to spend any money you may as well get the 2008 version. The max Zs for MCBs is given by the supply voltage divided by the max current required to operate the magnetic part of the MCB, i.e. for B type x5, C type x10, D type x20.
    As an example, for a 6A MCB @ normal mains voltage is 230 / (6x5) = 7.66 ohms. This is the maximum tabulated value, not corrected for temp.
     
  5. Lectrician

    Lectrician

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    Amtech has all the max figures for normal BS devices, corrected and uncorrected. It auto checks for you.

    It does not have the data for devices such as manufacturers MCCB's, ACB's etc. You need to use manufacturer data for these, and this is nearly always just a few clicks away once you find the manufacturers website.
     
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