On 7/4/2013 8:13 PM, gregz wrote:

An arc fault breaker is not also a ground fault is it. Are there some ?


AFCIs include ground fault protection. I believe it is required at 50mA
or less and is provided at 30mA. The cpsc.gov link I posted has
information on ground fault protection and why it is included.

GFCIs will trip with a ground fault of 5mA, so AFCIs don't replace
GFCIs. Another difference is that GFCIs have a couple additional
components that will trip the GFCI whenever there is a downstream N-G
connection, load or no-load. AFCIs will trip with a N-G downstream
connection (as gfretwell wrote) but there has to be a load to produce a
voltage drop on the neutral wire.

I don't think the NEC requires both GFCI and AFCI protection at the same
location. GFCI wire-through receptacles can be used downstream from AFCIs.