Low Voltage Distribution Upgrade – St Edmund Hall, Oxford
Upgrades to the LV distribution and cabling – Completed 2020
Project description: The supply, installation, testing and commissioning of the
upgrade and replacement mains low Voltage (LV) distribution system
Large parts of the existing LV Distribution system has been installed for nearly 40years and is due for
upgrading. Some elements have been upgraded in recent years and this project is proposed to continue
this.
There is existing loose switchgear which contains asbestos which is due to be replaced in order for the
college to safely maintain the system. The majority of the college is currently fed from this switchgear.
In 2015 SSE contracting installed a new switchboard with the intention for this to replace the existing
switchgear.
The purposed of this project is to upgrade existing submains and connect these to the new switchboard
whilst also diverting some existing supplies to the new switchboard. The ultimate aim is the strip out and
safely dispose of the existing redundant switchgear.
Works: New cable tray containment systems were installed to various locations, externally, internally and within an underground service area, enabling the installation of new XLPE/SWA submain cables. The cables, including 2no 185mm2 4core’s were installed on agreed dates and times with the college. Programming and achieving these works on the agreed date/time was essential to allow the college to continue to operate smoothly. Some of the cable runs were well over 100 metres long! We carried out all necessary cable and protection device calculations.
Some builders works were required, core-hole drilling, access panels and fire stopping was all provided by our sub-contractor, Richard Ward Oxford Ltd
Our next task was to install new isolators and a switch panel-board, replacing the existing equipment. All new LV switchgear and protective devices have been manufactured by Schneider to provide compatibility with the existing installation.
Having consulted, planned and agreed electrical shutdown dates with St Edmund Hall, we formulated a programme and set to work swapping the supplies from existing to new. Firstly, the asbestos containing material(ACM’s) were removed, we were then able to disconnect and remove the electrical equipment and connect the new. Some new cabling was connected to the existing switch-gear. This switch-gear is to be replaced as part of future projects.
Existing final circuits(sockets, lighting etc) were incorporated into the upgrade to. We installed new distribution boards, consolidating the existing final circuits, ensuring ongoing maintenance works can be carried out by the college as efficiently as possible.
New emergency lighting was installed throughout the plantroom, labelled and the college logbook updated to reflect the changes. Certification was provided too, as standard. Thorn ‘Aquaforce’ self contained 3hour fittings were selected.
Metering was installed and commissioned as part of the new installation. Readings can be viewed on the display screen but they also have Modbus protocol compatibility, enabling connection to a remote monitoring system.
Updated drawings, technical information and Electrical Installation Certification was provided.