RED Electrical - Solar Panels in Longton, Preston, Lancashire - A Case Study
This customer in Longton, Preston wanted to make the most of the top tier of the feed in tariff, and asked us to quote for a system of 20 solar panels. We designed and installed a 3.9kWp system.
The property has a large roof with interlocking concrete tiles, the front elevation of which faces between south and south-west (approximately 39°). The pitch of the roof is approximately 39°.
There is no overshading. The solar panels were to be installed as two rows of ten in the centre of the roof.
The Roof Installation
Roof anchor being installed
The anchors are installed onto the roof spars above the roofing felt, to fully maintain the weather protection of the roof.
Roof anchor fitted
They are each secured with two galvanised coach screws to the spar.
All anchors fitted
All the anchors are secured in this way, then the tiles overlaying have channels cut into their underside to accommodate the anchors. They are then carefully moved back into place to their original position. This leaves the anchors protruding from beneath the tiles and leaves the roof as watertight as it was before.
Mounting rails fitted
Aluminium rails are then fixed across the rows of anchors, secured with corrosion-free stainless steel fixings.
Solar cable entry
The cables from the solar panels are enclosed within flexible conduit as they enter the roof via a modified tile vent. This is our preferred method of cable entry as it protects the high voltage cables from damage and from being confused with aerial cables.
All solar panels in place
All solar panels in place
The solar panels are then secured to the rails using proprietary aluminium clamps with stainless steel fixings.
The Electrical Equipment
An EverSolar 3200TL inverter was chosen for this installation. The equipment, pictured below, is as follows:
The inverter and isolators
- D.C. cables from solar array
- D.C. isolators (for maintenance purposes)
- EverSolar 3200TL Inverter
- A.C. isolator (for maintenance purposes)
The meter and consumer unit
- OFGEM approved meter to record generation
- Dedicated consumer unit
Finally, an additional electric meter is installed (pictured above, no 5). This measures the output of the solar PV system and is used by the energy company to calculate the payments that the owner will receive under the Clean Energy Cashback Scheme.
A DIY Kyoto Wattson wireless energy monitor was installed. This clever device monitors both household energy usage, and solar electricity production. It displays these figures instantaneously, and can show net power consumption.
In the picture to the right, the solar panels are producing more than the household appliances are using, hence the negative figure. Wattson logs the information, which is downloaded periodically to a PC via a USB port. The data can be viewed and plotted onto graphs.
Total annual yield from system = 3262kWh, worth £1400 per year.
Annual yield by month