Experience example

Upgrading Water Treatment Plant Legacy Electrical & Control Systems

"Change before you have to." - Jack Welch


Water & Sewerage

Water Treatment


The client is a water and sewerage utility responsible for managing over $2bn worth of assets. The client had identified one of their key water treatment plants supplying a major metropolitan area needed an electrical and control system upgrade.

The project was complex as the plant needed to be kept operational while the upgrades were undertaken. It involved working closely with the client and the power supply authority, maximising safety whilst minimising operational disruption.

A staged approach was needed which involved development of a detailed cutover plan in conjunction with the client, installation of the new equipment and then cutover and testing in accordance with the approved cutover plan.

Cromarty were selected to deliver the works.


Works involved installing:

  • a new MSB
  • a new Lime/Alum dosing MCC
  • several local control panels
  • temporary cabling between the existing switchboards and new boards
  • new mains between the supply transformer and new main switchboard

Scope also included:

  • modifying the site PLC code
  • updating the existing local SCADAPack RTU
  • maintaining the local and headend SCADA system system functionality
  • decommissioning and removal of the old main switchboard
  • removal of all redundant cabling and cable support systems


The project was highly successful. The client didn't experience any operational impacts, the clients customers did not experience any disruptions in their water supply and above all although the changeover was highly complex there were no safety incidents.

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