Delivering power to the billion-pound St James Quarter complex
St James Quarter is as big and challenging as construction sites get. Located on a constrained site at the heart of the historic city of Edinburgh, the £1billion development mixes retail, leisure and living in one giant complex.
About the project
To enable construction of such a large and complicated city-centre project, main contractor Laing O’Rouke (LOR) turned to WysePower to provide the huge site with temporary power, lighting and heat.
The entire footprint of the site was being developed so a major challenge at the outset was for WysePower to devise a scheme to provide electrical power to LOR’s 12 tower cranes located around the site.
Tower cranes have a very high power demand. To minimise the size and length of power cables required, WysePower used its extensive database of site-equipment power consumption. The database contains records of measured power (recorded from previous projects) for all major items of plant, including the specific models of tower cranes used on this project.
Using its data, WysePower determined the typical load profile for each model of crane in order to optimise the power supply accordingly. “We were able to say: ‘we’ve physically measured these models of tower crane on previous jobs so we know what they are going to draw in terms of power, the likely load and start-up power’, says John Buchanan, WysePower’s European Operations Manager.
Even after optimisation, the cranes’ high power demand meant the cables were still large. Instead of using unwieldy multicore cables, WysePower split the supplies into smaller-diameter, more manageable, single core cables.
The scale of the development meant these single-core cables had to travel long distances. No one had designed a single-core scheme at this scale before, which meant that WysePower had to develop a methodology to de-rate the cables’ current carrying capacity to ensure they did not overheat. WysePower then worked with electrical industry body NICEIC to agree its approach and methodology. “Nobody had ever done anything like this at this scale before,” John explains
Having developed the design, WysePower sat down with LOR to agree the cable routes.
Additional temporary site services
Other site services supplied by WysePower included: the temporary fire alarm and evacuation system, which sent text messages to site security to tell them the location of the incident. The fire alarm stations were enhanced with the addition of first aid alarms, these sent text messages to first aiders to tell them the location of the incident.
WysePower was also responsible for the temporary provision of CCTV cabling, water, drainage and heating and for dealing with rainwater run-off. It even put in temporary electrical supplies for the light and laser show to provide a bit of pizazz on the shopping centre’s opening night.
Richard Mulholland, Senior Construction Manager at Laing O’Rouke says: “On Edinburgh Saint James, rather than use our in-house company we decided to go out to tender on the temporary electrics. After interviewing Mark and his team we decided to appoint WysePower.”
What our client said
He continued: “Appointing Wysepower has been a success for us: as the project progressed we increased our tower crane numbers; we changed the sequence of works in response to client requirements; and, along with all the additional works, they maintained programme and worked tirelessly to achieve the targets. I would not hesitate in appointing WysePower on any of our projects.”
