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MCCB settings (Isd)

E95

Hi all,

How should the Isd value for an MCCB be selected?

Is it essentially any setting prior to the result of the adiabatic equation for the line conductors?

Thanks

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    Long time (Ir) and short (Isd) time protection. Example : In = 2000 Amps. Set the long time dial to 0.7 and multiply by 2000 gives you 1400 Amp (long time) set (Isd) to 3. (3) multiplied by 1400 Amps gives you a (Isd) of 4200 Amps. So now Co-ordination/selectively with other protective devices needs to be studied. And max impedance values can be calculated and verify disconnection times are met.

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  • 0

    Long time (Ir) and short (Isd) time protection. Example : In = 2000 Amps. Set the long time dial to 0.7 and multiply by 2000 gives you 1400 Amp (long time) set (Isd) to 3. (3) multiplied by 1400 Amps gives you a (Isd) of 4200 Amps. So now Co-ordination/selectively with other protective devices needs to be studied. And max impedance values can be calculated and verify disconnection times are met.

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