The brief
A major fire had left the works without its main switchboard. The site still had critical plant to run, so a new 4000 A primary switchboard had to be installed and every motor control centre moved onto it, without losing control of the plant along the way. The work was in a hazardous area with hydrogen sulphide (H2S) present, much of it in confined spaces.
What we did
- Planned shutdowns: we coordinated multiple critical shutdowns with the client, moving each MCC onto the new switchboard in turn so the site's critical plant was only ever off for planned, agreed windows.
- New switchboard: a 4000 A mains incoming ACB, broken down to three outgoing ACBs and multiple MCCBs.
- Temporary generator: a 1500 kVA generator fed the new switchboard through its own ACB, interlocked with the transformer mains ACB, so the plant stayed supplied while the new cables from the switchboard to each MCC were connected.
- Transformer connection: the new switchboard was fed from the 2 MVA 11 kV / 415 V HV/LV transformer on 630 mm² cable, four per phase.
- Heavy cabling: multiple 4-core 240 mm² cable runs of over 100 metres, and several 2000 A supplies on two 630 mm² cables per phase.
- Hazardous area and confined spaces: every member of the team was fully trained for confined-space entry, with procedures in place for every activity and standby men during operations.
The result
The works now runs its plant from a new 4000 A primary switchboard, with every MCC transferred across through planned shutdowns agreed with the client, and the whole job carried out under confined-space and H2S controls.