How to install Solar Century's C21 tilesAugust 9, 2008 5:42 pm
The following steps are a guide to installing Solar Century’s C21 Solar PV tiles.
Each installation should be individually risk assessed; however, the following safety equipment is likely to be required:
• Access equipment such as scaffolding and roof ladders.
• Safety goggles and gloves for use with drills and grinders may be required.
• A tool belt to keep hands free for moving around pitched roofs and ladders.
• Protective footwear should be flexible enough to allow free movement on a pitched roof.
Anyone carrying out the mechanical installation of C21e tiles should be trained and competent at general construction site practice, but should also have the following specific training:
• Safe working at height
• Safe ladder use.
Standard roofing safety procedures should be followed when installing C21e tiles.C21e tiles do not present a risk provided they are handled appropriately however, the following things should be noted:
• Once a C21e tile is exposed to daylight, it generates a direct electrical current (DC) and cannot be switched off. The C21e tiles are pre-wired with touch-proof connectors so electrical shock cannot occur during general handling, but care must be taken not to expose the terminals or cut live cables, to expose bare wires.
• The voltage generated from a single C21e tile is not considered dangerous, however, as the tiles are connected to each other the voltage increases and so does the potential for harmful shock.
• DC voltages are more hazardous than AC voltages due to the nature of the shock, which causes muscle contraction and can lead to the victim of a shock to hold onto the conductor.
• The danger of an electrical hazard on a roof can be increased because of the associated danger of falling after the initial hazard.
• The C21e tiles contain laminated glass and are subject to fracture if handled incorrectly. Care of handling must be a priority and any damaged panels must be wrapped to prevent further damage and to avoid the risk of injury.
These are the system designers responsibility, however the roofer should be aware of the following:
• C21e tiles should only be ever fitted alongside roof tiles that have been approved by solarcentury.
• At least one concrete tile should be laid between any C21e tiles and the verge, ridge, or eave of the roof. This should also be considered when the tile interfaces with a roof window, ventilation tile or similar. C21 tiles should not be adjacent to any mortar or be covered by any flashing.
• Tiles should never be laid below any boiler flue or overflow outlet where the tile will be exposed to hot gases or fluids.
• Be aware of potential near shading issues from satellite dishes, chimneys, TV cables laid over roof surface etc, which will reduce the system performance.
• Eave and dry ridge vent systems should be used to allow ventilation behind C21e tiles to ensure optimal generation performance
• Edge Clips to prevent tile uplift may be required for particular installations. This should be advised by the system designer.
• Open Circuit String voltages should be stated by the designer to allow onsite string checks by the roofer.
• Batten Gauge should be 330mm (minimum) to 345mm (maximum). Any spacing less than this will shade the PV element of the C21 tile and significantly reduce performance, any spacing greater than this will reduce the headlap and potentially lead to weather tightness concerns. For the latest C21e tile specification, please consult the C21e Product Data Sheet which is available on the solarcentury website: www.solarcentury.com
4.Roof Tile Compatibility
C21e tiles (C21e M52D) are compatible with the following roof tiles.
Marley (Eternit) Modern, Duo Modern
Redland (Lafarge) Mini Stonewold
Russell (Cemex) Grampian, Highland
Sandtoft Calderdale Slate
Scott (CRH) Slemish Mk2
Quinn Western Slate
C21e tiles should not be installed with any other roof tiles without the prior approval of solarcentury. For the latest C21e roof tile compatibility list please refer to the C21e datasheet, available at www.solarcentury.com
C21e tiles can be laid in different ways according to the available roof area and the manufacturer’s fixing specification for the roof tile that has been chosen. The System Designer should provide the layout before you start work.
i) Roof Preparation
A conventional roof build up is suitable for use with C21e tiles, however, we make the following recommendations:
• Use a breathable roofing membrane, or similar.
• Use 38mm x 25mm Tanalised battens nailed to rafters not exceeding 600mm centres, in accordance with BS 5534-1.
• Set roof out with vertical chalk lines indicating the position of the C21e tiles using the alignment notches on the top edge of the C21e tile as a guide. (A C21e tile is the same length as 4 conventional concrete roof tiles)
• Lay the lower courses of concrete tiles to the point where the C21e tiles are to be fixed and adjust the shunt between the concrete tiles as necessary to align with the chalk lines.
ii) Study the System Designer’s roof layout, and understand the tile interconnection arrangement. Work out where the field cables will need to enter the roof.
iii) When ready to begin installation, unpack the tiles in accordance with the guidelines.
iv) Place the C21e tile with the nib resting on the batten, as with a conventional concrete tile.
v) Feed the cables between the tiles as directed by the System Designer’s plan. When running cables vertically they should be passed under the battens, to avoid being trapped or tensed.
vi) After placing the next tile in the system designers plan on the batten, connect the cables as shown between the two tiles. Black (negative) to red (positive) Push the connectors together firmly to ensure there is no gap between them, avoiding any undue twisting.
vii) C21e tiles should be fixed using the 4.5mm x 40mm self tapping stainless steel screws with washers, as supplied. Start at the right hand side of the C21e tile. Use a cordless screwdriver to puncture the thin layer of material at the back of the hole with the screw provided, and fix the tile to the batten.
viii) Continue from right to left, using all four fixing points to attach the tile to the batten. Repeat Steps 4 to 8, following the System Designer’s roof layout.
ix) 9. Once 5 tiles have been laid, it is necessary to perform a Continuity Check to ensure that all of the C21e tiles are connected properly and that there are no electrical breaks in the the string. Use a voltmeter to check that all of the connections are working after installing each set of five tiles (refer to the system designers diagram for voltages). Attach the black field cable (supplied) to reach between the first and current tile. Using a voltmeter, check the voltage that is generated and compare to the System Designer’s reference diagram, making a note of the test results. If the voltage generated is within the limits specified, remove the field cable and proceed with the next set of tiles. If the voltage falls outside the specified limits, check that there are no loose connections and re-test the voltage.
x) At the end of each string, as shown on the system designers layout, connect the cable from the tile to the same colour field cable (provided). Feed the end of the field cable through the overlap in the membrane, so that it is easily accessible from within the loft space,for onward connection by the electrician.
xi) Ensure any dust or dirt is brushed or gently cleaned off the tiles after installation. Do not use abrasives or chemical cleaners.
xii) SYSTEM COMMISSIONING – After the String Continuity Check and once the field cables have been fed into the roof void the C21e tiles will be ready for the electrical system installation, which should be carried out by a suitably qualified electrician. If the String Continuity Check has been successful there should be no further need to access the C21e tiles on the roof.
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