We have a 2 section Sq D QED style switchboard . The first section has a 1600 amp main breaker that feeds the section section . We need to pull out some cable's and install larger feeders for a new air compressor in the second section . Both sections have a label that says " Prohibited " for the arc flash rating . Can we just isolate the main breaker and work inside the second section or would we need to isolate the feed to the main breaker too ???