Detached structure question

[cbuell]

This is a question for Mark or Paul----or anyone that knows the answer. Can multiple circuits be run in the same conduit to a detached structure or should there be one circuit feeding a distribution panel in the detached structure? (currently one 15 amp lighting circuit and one 20 amp receptacle circuit---both romex type wire)

[Mike Whitt]

As outlined in the 2005 NEC
225.30 Number of Supplies.
Where more than one building or other structure is on the same property and under single management, each additional building or other structure that is served by a branch circuit or feeder on the load side of the service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.

What you describe would be a violation of the NEC and should be written up as a safety hazard.
The next section (225.31) also requires that there be a disconnect located at the building to disconnect all ungrounded conductors. In a residential application this disconnect could be a single pole switch or a set of three way switches.

[Paul W. Abernathy]

The best application here would be to either reduce it down to one of those lines to the garage and put it on GFCI....if that was not enough to run the lights and receptacles...then tell them to run a new feeder to this detached location ( 4 wire setup...dont get into the exceptions ) and install the remote distribution panel and GES at that detached location and be done with it...

[cbuell]

Thanks Mike and Paul, Paul that is pretty much what I told them. One circuit just won't be enough----the two they have are already insufficient.

[Paul W. Abernathy]

Oh yeah....then dont even make it complicated...no need for additional info on the possible options....the one they should Do is have a new (4 wire ) setup run to the detached garage and have it done properly.

I wont even go through the 3 wire exceptions...you all have heard me talk about that enough....4 wire setup is always going to be safer because of the knowns.....then the unknowns wont get ya.