Choosing solar is a great decision, but it’s vital that you get it right, especially if you’re investing in a new-build. The last thing you want is an expensive run of modifications and repairs hot on the heels of what was probably your biggest ever spend! Here’s five tips to set you along the right track.
Rough in your cables before your walls are sheeted
If you want the cables from your solar installation hidden, this often needs to be performed before your internal walls are sheeted, (low set brick veneer walls are one exception). Every sparkie knows this. But we’ve found not every sparkie knows how these solar cables need to be run.
The cables from your solar panels are different to your other wiring as they can reach up to 600V DC and can’t be protected by a safety switch or circuit breaker. The cables are live until the sun goes down (or the entire system is disabled) and so there are very tight regulations around the location, materials and design of solar DC wiring.
For this reason, you should play safe and use a CEC-accredited solar installer to perform the design and build of the wiring. If you want your wiring to be out of sight, you need it done correctly and in accordance with the AS/NZ3000 standards. Otherwise, if a cable is damaged, you’ll face the extra problems of dismantling and rebuilding a wall to get to the wiring.
Choose panels with a slow degradation rate
If you’re planning to live in your new home for at least ten years then it makes good economic sense to buy panels with a slow rate of degradation. Better-quality panels lose around 0.25% of their efficiency a year compared to the cheaper ones, which can degrade by 0.7% or more every 12 months. Over the 25 years that your panel manufacturer promises you, you could bag an extra $4,000 or more in free electricity with the pricier panels.
Position your inverter right
One of the best things about designing and building your own home is that your get to decide where your plug outlets and windows go. You also get to specify where things like your switchboard and meter go, so if you can place your inverter as close to the switchboard as possible, you’ll be keeping voltage rise and costs to a minimum. A south-facing wall is ideal.
Hardwire your monitor
If you’re planning to connect your system to the internet for monitoring then it’s best to go a bit retro and directly hardwire the monitor into a modem rather than rely on WiFi. A LAN cable will offer the stability and continuity of service that WiFi can’t quite manage yet. Map out where you want the inverter to go so that you can then work out the optimal place for the cabling.
Optimise your roof design for solar
While you don’t want your entire home’s design to be a slave to the sun-god, you can certainly pay homage to it with your roof. Your northernmost roof orientation should be one long, unobstructed plane so that you can have long lines of panels, with no satellite dishes, windows, vents or other structures in the way.
Think about the area immediately around the house – for any trees that might grow over the years and shade the panels, for example. An experienced solar installer will be able to advise you here.
Choose single or three-phase supply
Most smaller homes are single-phase, they have just one live wire. If you have a larger home with an extensive aircon system, for example, then you might have three-phase wiring. However, even if you’re only planning a smaller build, three-phase may be the way to go as you could feed more power back to the grid and get paid. In Queensland, a single-phase system can only feed back 5kW, but a three-phase one can export up to 15kW. With half-decent tariffs on offer, it makes sense to go three-phase from the start, even if your system starts off quite small – you can always add to it later.
