42kW solar PV installation, Merryfield Farm, Somerset

Installation, Solar PV

Merryfield Farm asked NWT to provide a solar PV proposal to supply electricity to their site. The system was to be mounted on a new cattle shed measuring approximately 50m x 30m. The system sizing was complicated slightly by restrictions concerning a cable that potentially needed to be upgraded to satisfy DNO requirements. On top of this there would have needed to be a new kiosk, and the larger connection would have meant that CT metering would also need to be installed. In the end, NWT recommended a slightly smaller installation than had been planned in order to strike the correct balance.

42kW solar PV installation, Merryfield Farm, Somerset


The inverters were wall-mounted externally within a purpose-built weather-proof structure. Each pair of panels has a power optimiser connected to ensure that the system delivers the maximum amount of electricity. From these the DC cables are connected to the inverters, and a new AC cable then runs across the other buildings back to the connection point.


Following our discussions with the distribution network operator it became apparent that the extra costs involved in upgrading the connection reached the point where an alternative should be considered. This was for several reasons:

  1. Because the upgrade WPD were requesting was going to cost several thousand pounds.
  2. Following the cable upgrade, they would also have required “CT metering” to be installed – adding further costs at the installation phase and also resulting in higher ongoing costs.
  3. By reducing the total system size, were are able to use a thinner cable to connect the system to the metered supply. Given that this was over a distance of approximately 150m, there were substantial cost savings to be made through using this approach.
  4. With the 42.12kW system we no longer needed to install a new kiosk

By installing the panels in rows, it was also possible to install without the need to cover any clear roof sheets, thereby not obstructing light from entering the shed.

Outline 12 bay cattle shed 42kW 2