Feeder for Detached Building Sub-Panel - 3 or 4 wires?

[Marty Tippin]

3 wire or 4 wire feeder from main panel to sub-panel in a detached building?

My detached building is fed with 4-wire (neutral is isolated from ground in the sub-panel), but it seems like maybe I should only be using 3 wire instead with a separate ground at the subpanel (the ground system for the sub-panel is the subject of another thread I recently started).

If I should only be running 3 wires to the sub-panel, can I simply disconnect the ground conductor in the main panel, tape it off and leave it in place?

[roger wiegand]

Current code requires 4 wires for a sub-panel in a detached building. At one time 3 wires was legal, but no longer. What you have now is correct, to my understanding.

[Andrew DiLorenzo]

It is my understanding that all sub panels require a separate neutral and a separate ground. If your sub panel is 220 volts, that means four wires.

[Mike Heidrick]

I ran four conductors to the new shed (two hots, a ground, and neutral) and also put in two ground rods there as well. I have disconnects off the meter (one for house and one for shed) and there fore the panel in the shed is considered a sub panel. Do not bond the ground and neutral in the subpanel.