outbuilding electrical disconnect

NEC requires an electrical disconnect at the service entrance to an outbuilding when fed from a main located elsewhere on the property. In addition to the two hots, the subpanel in the separate structure need to have the neutral and the ground also connected to the main panel (in most areas of the US this means whether or not you have a separate grounding point for the subpanel).
Now here's my question. In the newest NEC book from 2005 there is some screwy language about being able to disconnect all of the wiring at the mechanical disconnect. I showed this to my friend a retired electrician who wonders if it was written in English.
Has anyone seen a mechanical disconnect that is a true (i.e. four wire) disconnect for a structure? All the ones I have ever seen are three-wire disconnects and don't disconnect the grounding portion.
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why would anyone want to disconnect a ground?
sounds like a grossly bad idea........
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You would not disconnect the "grounding" conductors, however there are certain "hazardous" locations where you would disconnect the "grounded" conductors along with the ungrounded conductors.

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snipped-for-privacy@verizon.net wrote:

The code only requires the simultaneous disconnection of all UNGROUNDED conductors. It specifically forbids the disconnection of the Grounded Current Carrying Conductor unless that disconnecting means will also simultaneously open the ungrounded conductors as well.
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Tom Horne

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