If you are planning solar for your new home, you don’t want to get it wrong. There are some unique advantages you have from starting fresh. However, there are potential pitfalls you need to avoid. This article is going to look into five tips when considering a solar installation on your new build.
1. ROUGH IN / PRE-WIRE
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.
Solar cables in a home can reach up to 600V DC. They are different from all the other wiring in your house. Solar DC cable cannot be protected by installing a safety-switch or circuit breaker. The only time the cable is not live is when the sun is down, or the switch mounted beside your solar panels is turned off. For this reason, there are strict regulations about how and where Solar DC wiring is installed to prevent future damage to the cable.
We strongly suggest you don’t accept a builder’s additional extra of a “Solar Pre-Wire” on their contract. Chances are it’s worthless. We talk with customers who have paid for a solar pre-wire every week.
Nine times out of Ten the “Solar Pre-wire” either:
- Wasn’t carried out by a Solar CEC Electrician
It’s not that you can’t use a normal sparky to do the job, it’s just that they may not be familiar with the solar installations. It’s not something they do day in day out. Solar cabling from the panels to the inverter is DC, which as previously mentioned differs from conventional AC. The same methods are not used for both, so it’s recommended to have a solar accredited electrician do the job. A lot of builders use their current sparkies to do the works. There’s no guarantee that the cable run can be used for solar. However, even if a Solar CEC Electrician ran the solar cable, there’s still no guarantee the cable was run correctly as per the AS/NZ3000 standards.
- Wasn’t run correctly as per the AS/NZ3000 standards
DC cable must be run in HD conduit, must be clearly labelled, and must be able to move freely inside the wall cavity. This part often isn’t done correctly. If it can’t move freely, the AS/NZ3000 standards are enforcing “mechanical protection” at a minimum of WSX3.
In other words, we need to protect the cable with steel conduit or 1.6mm sheet metal. I haven’t talked to a builder yet who ran steel conduit for their solar pre-wire.
- Didn’t have adequate photos of the run
Let’s say the sparkie assures you that he used steel where required. That’s great – there’s a good chance we can use it. However, keep in mind the solar accredited electrician signing off on your solar system takes full responsibility for the internal wiring. They’ll want evidence. When I discuss new builds with people, they assure me provisions for solar pre-wiring is in their contract. However, when they go to find their contract to confirm, all that’s showing is a one-line item called “provisions for internal solar pre-wiring,” nothing else. You’ll be hard pressed to find a decent solar installer willing to put their licence on the line without evidence that the wiring was installed correctly. Photos, a full explanation and a “certificate of test and compliance” would help. If you don’t have them, request a refund and try to arrange your chosen solar installer to do the works instead.