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Automatic disconnection cannot be achieved in the time required

Julien Leblanc
I was reading art. 411.3.2.6 of BS 7671...

I'm wondering: except for the case where Zs is too high (caused by the length of the circuit, together with the CSA), are there other situations where automatic disconnection times cannot be achieved ?

Maybe some special types of loads or circuits ?
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    Another example where bonding is more important, is in TT installations that can suffer more serious ground rise during faults, not necessarily just faults on the circuit  in question.

    And generator derived supplies which are no able to provide a significant over current.

    There are other cases where there may not be ADS of the conventional kind (protection omitted) for certain safety critical things (sprinkler pumps come to mind as not being the sort of thing you may want on an RCD) and limiting the possible touch voltage is an alternative. I should say that the modern RCD has knocked this into a cocked hat, as in all but the most controlled situations, bonding everything  is not that practical.
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    Another example where bonding is more important, is in TT installations that can suffer more serious ground rise during faults, not necessarily just faults on the circuit  in question.

    And generator derived supplies which are no able to provide a significant over current.

    There are other cases where there may not be ADS of the conventional kind (protection omitted) for certain safety critical things (sprinkler pumps come to mind as not being the sort of thing you may want on an RCD) and limiting the possible touch voltage is an alternative. I should say that the modern RCD has knocked this into a cocked hat, as in all but the most controlled situations, bonding everything  is not that practical.
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