This article is new to the 2005 code. Am i to assume that this affects the sizing of gutters? I am installing a gutter above a service in the middle of 2-200 amp feeders in 2" conduits to accommodate the installation of autotransformers. there will be 2-2" conduits in the top of the gutter and 6-2" conduits in the bottom all containing 3/0 conductors. what size gutter do i need?