1. Problems with UPS racks last week... During the DSS tests on the weekend Jun 1-2 all racks connected to „interruptable“ UPS were cut by DSS at some point. After the conclusion of the tests, 4 racks failed to be able to switch on under remote control: Traced to failure of the motor acting on the breaker in the switchboard Y0314A1 (MDT Can PSUs) Y0514A1 (Endcap alignment) Y0705S2 Y2705S2 For USA15 problem was solved with replacing the failed motors. More difficulties in US15: Y0705S2 tripped on trying to switch back on, traced to bad first installation of the replacement motor, Solved. Y2705S2 was found with 1 phase showing an instable voltage, finally traced on Thur afternoon to a loose connection on the switchboard. Resolved. 48V Service CSC, MDT, RPC, TGC Note: Except for Y0514A1, DSS actions on the listed racks have been very rare, for US15 UPS eg last in June 2012 Appears no further tests needed for the moment....

2. Consolidation of Electrical Distribution for Big Wheel Racks (A + C) During 2011 running it was found that MDT mini-racks on BW A and C are not properly monitored electrically. They are daisy chained in a „wild“ fashion on random TGC racks electrically (with non halogen-free cables)  Scheduled to rectify in LS1 Plan established by Wieslaw, Sergei and TC to install 4 new electrical lines per side, to connect MDT mini-racks with separate breakers on the EXD107/EXD209 switchboard as for all other racks

3. Consolidation of Electrical Distribution for Big Wheel Racks (A + C) Breaker installation will imply cutting power for 1 or 2 days per side for the full big wheel Sergei informed us the work can be done in June/July  Do we have major constraints from our side ?

4. Rack Turbine Replacement campaign, USA15 + US15 + UX15 There has been no progress from electrical team to propose a time slot for the turbine replacement campaign. We have now been asked by OPM to go the opposite way and define a time period suitable for us instead Replacement campaign can be split into USA15 racks, quick, few days) US15 – 1 CSC rack only, anytime Cavern, racks on HS and HO Racks on Big Wheel -- major operation During campaign in UX the detector has to be off !! Should insist on a validation of monitoring mapping after the work, we rely on it for interlocks Several weeks ? Suggestions and Ideas on When to Do it ?