After the introduction of the Circuit Disconnector Boxes (CDBs) in the HL-LHC baseline in 2020 as seen in the HL-LHC engineering change request LHC-RP-EC-0005, the deliverables required to connect to the Inner Triplet (IT) powering cluster are already installed in their first destination, the HL-LHC IT String, before their installation in the HL-LHC technical galleries during LS3.

The CDBs are instrumental to ensure safety measures and easy access for interventions and regular checks of the electrical compliance of circuits powered through DFH cold feedboxes in HL-LHC.

The first CDB systems arriving to the HL-LHC IT String will serve as a pre-series installation to guarantee the proper interfaces with the warm and cold powering systems and will considerably help in preparation for the installation in the tunnel. The three CDB models foreseen for HL-LHC are used in the HL-LHC IT String which are the ones designed for 18 kA, for 2 kA and for 0.6 kA currents.

The installation of the CDBs marks an important milestone since it consists of the first equipment in the HL-LHC IT String delivered and installed by a WP other than the WP16 deliverables. 

Samer Yammine, HL-LHC WP16.