INTRODUCTION
1.1 BACKGROUND
Solar is a cleaner, more affordable form of electricity. Rooftop solar photovoltaic
(PV) panels generate electricity using the energy from the sun. That electricity
powers the home during the daytime, with any excess being sold back to the
homeowner’s electricity supplier at a negotiated rate. When there is not
enough solar generation to meet the home’s needs, the energy is supplied from
the national grid. Solar helps lower home energy costs and reduces
environmental impacts. Overseas research also shows that solar homes sell for
higher prices and more quickly.
Pre-wiring for solar when building a new home, or renovating an existing house,
is inexpensive and makes it easy for the homeowner to add solar panels
whenever they are ready.
1.2 DESCRIPTION OF SOLARADVANTAGE
A home with solarAdvantage has been pre-wired to make it easy to install a
rooftop solar system in the future. It is also pre-wired for an electric car charger.
The essential components that are hard to retrofit are integrated during
construction at minimal cost, in the same way that inexpensive conduits for
central vacuum systems are added during the build.
solarAdvantage homes have:
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A roof location of suitable size, pitch and orientation.
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Conduit and draw wire from the switchboard into the attic space.
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Wiring from the switchboard to the proposed electric car charger
location.
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A label on the switchboard notifying the owner that the house is ready
for solar.
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Proposed solar panel locations.
1.3 OVERVIEW OF A SOLAR SYSTEM
Key components of solarAdvantage and a solar system:
Conduit – Carries wiring from attic space to switchboard allowing for easy
connection to solar panels. A separate circuit between the garage and
switchboard allows for an electric car charger (7kW max).
Solar panels - The panels are made of photovoltaic (PV) cells, which convert
sunlight into direct current (DC) electricity throughout the day.
Switchboard - The AC electricity is sent from the inverter to your switchboard
and then into your home to power your lights and appliances.
Power grid - Your home is still connected to the grid. You will still need grid
power at night and when sunlight levels are low.
2.0 SPECIFIYING THE SOLAR SYSTEM
Before pre-wiring for solar it is important to verify that the home is suitable for a
solar system. The following diagram shows the process:
solar à roof check – roof orientation and pitch, cladding type, available space,
shading à Cable run – minimise the distance, accessible in the future, can be
run.
2.1 LOCATE THE SOLAR ARRAY
It is important to check if a solar system can be fixed to the roof of the building.
When selecting a suitable roof, key factors have to be taken into account
including:
Orientation
Panel orientation between west and east.
Pitch
Minimum roof pitch is 5°.
Cladding type
Cladding type should be compatible with solar mounting
frames.
Shading
Solar panels should be installed in a location that is shade free
between 9am and 4pm.
Adequate area
There should be enough space on the roof to fit the required
solar array
2.2 ORIENTATION
Orientation of solar system should be between 90° west to 90° east of north.
Systems orientated south of this are not suitable in New Zealand.
Note there will be performance loss the further the array is away from north,
especially on steeper roofs and at southern latitudes
2.3 PITCH FOR SOLAR
Minimum roof pitch for fixing directly to roof is 5°.
2.4 CLADDING TYPE
When assessing a suitable roof, the cladding type must be strong enough to
withstand the weight of the solar panels. The most common roof cladding types
are tin and tiled
Corrugated profile
Masonry tile - curved *
Metal tile *
Membrane
(Plinths required at
build time)
Trapezoidal profile
Slate
Masonry tile - flat *
Standing seam *
* Roof type may incur additional installation costs.
2.5 SHADING
Shading is an important aspect when considering a suitable roof for a solar
installation. Ideally, solar arrays should be installed in a shade free location
between 9:00am and 4:00pm throughout the year. This requirement includes
even small obstructions such as:
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Vent pipes
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Chimneys
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Satellite dish and/or aerials
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Dormer windows
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Trees
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Other building structures
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Surrounding hills
2.6 ADEQUATE AREA
After assessing the other aspects of the roof it should be confirmed that there is
adequate area to install the solar system with at least 300mm of space between
the roof edge and the system. The shape of the roof will determine the size and
location of the system.
The diagrams below show the area required for different sized systems and
layout options.
Some possible examples of system sizes:
Small
system
– 6 modules
Medium
system
– 8 modules
Small
system
– 6 modules
Medium
system
– 10 modules
Large
system
– 14 modules
Large system
– 12 modules
3.0 SOLAR PRE-WIRE INSTALLATION
These guidelines allow for a string inverter or a micro-inverter solar system to
be connected in the future.
3.1 STEP ONE: MOUNTING FLUSH BOX
The flush box is mounted in the location that would be used for the inverter (if a
string inverter is decided on at the time of installation). If a micro-inverter system
is decided on then the cable will pass through, and blank plate will remain in
place.
The flush box should be located below the designated location for the inverter this is usually adjacent to the switch board. It should be mounted at 1200mm
from the floor.
Extra nogging may be required to allow for the future installation of the inverter.
Nogging should be installed at 1900mm and 1600mm from the floor level.
3.2 STEP TWO: RUN CONDUIT
Conduit is to be run from the switchboard to the flush box and from the flush
box to the ceiling space. The conduit entering the roof space should protrude
by at least 50mm to facilitate joining on additional conduit in the future.
The conduit must be HD solar rated 25mm conduit (eg Marley Solar
Conduit) which is readily available from most electrical wholesalers. This can
easily be identified by the words “SOLAR T HD CONDUIT” printed on the
conduit. It is important that this conduit is not substituted for regular conduit.
Where there is a considerable distance between the flush box and the ceiling
space, a draw wire should be installed.
The conduit must be appropriately secured so that it does not become
dislodged inside the wallspace.
The ends of the conduit should be capped to prevent the ingress of insects etc,
these caps will be later removed when the future PV system is installed.
Label each end of the conduit with “RESERVED FOR SOLAR CABLING”.
3.3 STEP THREE: RESERVE MCB LOCATION
To ensure that there is available space in the future, a switchboard blank
module should be installed in the board adjacent to the main switch. This will be
removed when the solar system is installed and replaced with the solar supply
main switch.
Label the blank module with “RESERVED FOR SOLAR”.
3.4 STEP FOUR: COVER PLATES
Once the building has been lined, the flush box cover plates can be fitted.
If you have any technical questions, please contact a solarcity solar specialist on
0800 11 66 55.
4.0 ELECTRIC VEHICLE PRE-WIRE INSTALLATION
4.1 STEP ONE: MOUNTING FLUSH BOX
The flush box is mounted in the location adjacent to where the Electrical
Vehicle charger will be located. Keep in mind that this needs to be near the car
parking space, but protected from the elements. In the garage is ideal.
The flush box should be mounted 1100mm from floor level, and have 300mm
clearance on all sides.
4.2 STEP TWO: RUN AC CABLE
Run the AC cable between the flush box and the switchboard, ensuring enough
excess is left at each end for termination in the future. The cable must be made
safe at each end with terminals blocks to prevent inadvertent short circuits.
Ensure that the cable is appropriately sized for a 32A load. 16mm TPS is
suitable for a cable run of up to 20m. completely surounded in insulation. It is
the responsibility of the installing electrician to verify cable sizing for the site
specific installation.
2
Label each end of the cable with “RESERVED FOR EV CHARGER”.
4.3 STEP THREE: RESERVE MCB LOCATION
To ensure that there is available space in the future, a switchboard blank
module should be installed in the board adjacent to the main switch. This will
be removed when the EV charger is installed and replaced with a MCB.
Label the blank module with “RESERVED FOR EV CHARGER”.
4.4 STEP FOUR: COVER PLATES
Once the building has been lined, the flush box cover plates can be fitted.
If you have any technical questions, please contact a solarcity solar specialist on
0800 11 66 55.