An Bord Pleanála (ABP) is a statutorily independent body and decisions taken and conditions imposed by ABP are expected to be adhered to by all project promoters, including EirGrid in the case of the North South Interconnector.
I will further refer the Deputy to the planning code as set out in the Planning and Development Acts 2000-2015 and the detail that is prescribed in the Planning and Development Regulations 2001-2015.
Details on the operation of Ireland's planning enforcement regime are set out at the following link. http://www.housing.gov.ie/sites/default/files/migrated-files/en/Publications/DevelopmentandHousing/Planning/FileDownLoad%2C31564%2Cen.pdf