Any electrical installation can have issues with space and completing to tight deadlines, but when the project involves installing a full electrical system in a space as small as 6m x 2.4m x 3m and availability of the accommodation is business critical to the client, the challenges are multiplied.
That’s the situation facing Ferguson Modular every day. The Inverurie-based company specialises in the design and manufacture of offshore accommodation and workspace modules that are used by the international oil and gas industry.
Roger Buckingham, electrical engineer from the company, explains, “Our high specification units are fully fitted out with all electrical, mechanical and HVAC services, plus interiors and internal equipment. The end result is a home-from-home for people who live and work in remote locations; the accommodation may be compact but it’s fully functional and very comfortable.”
Ferguson Modular’s units vary in size and internal layout, with a range of standard accommodation and workspace modules available. While the internal fit out of these units varies, the methodology for the electrical installation is the same for all the company’s products and all must adhere to stringent quality and safety standards.
Roger continues, “Our units are destined for offshore use and hazardous working environments, so they have to exceed UK and international standards for safety. They are also designed to cope in emergency situations, so all the electrical cabling used is fire-rated and the cable containment system must be able to withstand both fire and excessive vibration to ensure that the safety instrumentation system remains operational even in the most arduous conditions.”
The electrical installation for the company’s catering units is the most complex as these include cold store, galley and mess areas. The cold stores contain large commercial fridges and freezers, whilst the galley is fitted out with a wide range of electrical catering equipment including ovens, grills, hot plates and waste disposal units. “The range of equipment required makes the electrical installation more complex,” Roger says. “It means we have to accommodate various different power requirements which involves a wide range of power distribution hardware.”
The installation begins by bringing power to the module’s external recess, which also contains the condenser units for the air conditioning and the client’s power and signal interface junction boxes. From here, the team cables through to the internal switch gear and distribution boards contained within the internal service recess. Roger explains, “Because of the space restrictions, we need to keep things as simple as possible and we use a single feed three-phase power cable of large cross sectional area to provide the power consumption required.
“This main incoming cable is then routed through to the internal switch gear and distribution boards which in turn then supplies a network of smaller cables. All our power, signal and communications cables are contained on steel wire tray in the ceiling void. These feed the individual pieces of equipment, which vary depending on how the unit has been specified.”
The internal fit out of every module begins with a steel framework that is fixed to the ceiling of the steel container. The Cablofil steel wire cable tray is fixed to this frame, creating a robust containment system, and the isolation switches for the unit’s electrical equipment are also fixed to this frame. Roger continues, “The ceiling void is typically just 400mm deep and this not only has to contain all the electrical cabling and containment but also the water pipes, compressed air lines and ducting for the air conditioning. Space is at such a premium that often the ventilation ducting is hard against the roof in order to fit everything in.”
Ferguson Modular use Cablofil steel wire tray containment system for the electrical installation because it is light and malleable, which allows the installers to ‘snake’ the electrical containment around the other services to make best use of the space. And, as the units often have to be shipped overseas and loaded onto oil rig platforms which have strict weight restrictions, Roger says the lightweight Cablofil tray helps the company to use more of the available weight on comfort features rather than services, making life that little bit nicer for the people who live and work in these remote, and sometimes dangerous, environments.
