Understanding the Latest Changes in AS 5033
Simplifying the New Solar Installation Standard (AS/NZS 5033:2021) for You
On Thursday, May 19th, 2022, the new Solar Installation Standard (AS/NZS 5033:2021) became mandatory after a 6-month transition period. For those of us working in the field, interpreting Australian Standards can be as enjoyable as a punch in the head. The new “Installation and Safety Requirements for Photovoltaic (PV) Arrays,” also known as “5033,” feels like going a few rounds in the octagon with Conor McGregor.
In this post, I’ll summarize the major changes in AS/NZS 5033:2021 and how we at Sunoxi will apply them. I’ll explain the new rules you need to follow to eliminate the despised rooftop isolator. You’ll also learn about drip loops and drain devices, and why we prefer the drain device. I’ll outline the number of disconnection points or rooftop isolators required in different scenarios—because deciphering this from AS/NZS 5033 alone can be quite challenging. Lastly, I’ll share a neat method for creating a triple parallel connection.
At the end of the post, you’ll find comprehensive signage and labeling requirements, including those mandated by 4777.1, all in one place. Additionally, you can download our version of the site plan and our site plan sticker kit.
Stay tuned for clear, actionable insights to make your compliance with the new standards as smooth as possible.
DC Cable Run
The most significant change to the standards is the option to remove rooftop isolators. However, if you choose to remove them, you must be cautious with how you route your DC cable through the roof cavity, ensuring it is either close to the eaves or at least 600mm above the ceiling.
DC CABLE COMPLIANT WITH IEC 62930
Before you start working in the ceiling space, ensure you have the correct cable. The solar cable you were using at the beginning of May is now only suitable for scrap. New regulations require solar cables to comply with international standard IEC 62930 and be rated for 1500 volts. The industry became aware of this change when the CEC published a notice on May 4th. Since then, manufacturers, suppliers, and installers have been scrambling to secure the necessary supplies. Ironically part of the reason for the cable change seems to be because the new solar standards say we can run up to 1000 volts d.c. on residential jobs. Except we can’t.
THE PROBLEM WITH 1000 VOLTS ON RESIDENTIAL
Everyone got a little excited when they found out the new AZ/NZS 5033 2021 standard permits 1000 volts on residential installations. Then, after the standards were published, some inspector spoiled the party and pointed out we also need to comply with AS/NZS 4777.1:2017 clause 2.3.
Installations in domestic dwellings shall not have a maximum d.c. voltages that span greater than 600 V.
So we’re still at 600 volts for resi until 4777.1 is amended. Australian Standards are only allowed to go through a couple of amendments before they need to be entirely rewritten. So that minor change isn’t going to happen anytime soon. But let’s get back to the good news.
DC Disconnection Point
Once you’ve obtained the new compliant solar cable and properly routed it as specified, congratulations—you can eliminate the much-despised rooftop isolators. Instead, you’ll need to install disconnection points, which are simply a pair of readily available and labeled MC4 connectors.
According to AS5033, “readily available” means you must be able to easily access the MC4 connectors for inspection or replacement without removing a solar panel.
They must be installed within 150mm of the panel edge and labeled according to the label guide provided at the bottom of this page. Later in this post, I will explain how many disconnection points you need to use.
Top Entry into Isolators
According to the previous version of AS5033, top entry into isolators was strictly prohibited. While we typically don’t use DC isolators next to Fronius inverters, it’s worth noting that this blanket rule has been reviewed in the updated standards.

DRAIN DEVICE
If you want to run your conduit neatly into the inverter, then you’ll need to make sure that the conduit doesn’t act as a water pipe. Many inverters don’t give you the option of running conduit all the way into the inverter – but Fronius does. Because we only install Fronius inverters, we install a “drain device” at the end of the conduit below the Fronius inverter. This protects the solar cable at the most vulnerable spot – while eliminating the possibility of water ingress. (We get our drain devices from PV Connections)
We then install multihole glands on the top end of the conduit under the panel. This reduces the risk of the drain even needing to be used – except for the odd drop of condensation.

MULTIHOLE GLANDS
Multihole glands are only required where the exposed DC cable enters a DC isolator or inverter without conduit. As mentioned earlier, I’m not a fan of cutting corners – I prefer accessible DC cables to be in conduit where possible.
However, to avoid water tracking into the roof, we’ll still use multihole glands for our panel interconnects cables that enter a ceiling space.
HOW MANY DISCONNECTION POINTS
One Friday night I asked a question on the “Solar Cutters” forum about the number of Disconnection Points required (4.3.3.1) in a particular setup. I realised many in the industry had the definition of string, array and sub array confused. Here it is in picture form, complete with the number of disconnection points (DP) or Roof Top Isolators required (RTI). After arguing my point with industry experts, and with the help of my mate Glen Morris, I believe the below examples are compliant with the AS/NZS 5033: 2021 standard.
EXAMPLE 1. DISCONNECTION POINTS
Note there is a gap between the panels on the blue array. It is irrelevant how large that gap is. Obviously, a disconnection point does not need to be adjacent to every panel in the array. Nowhere in the standard does it say that every panel in an array needs to be adjacent to one another. Therefore, if the disconnection points (MC4’s) are adjacent to just one panel in the array, it is logically considered adjacent to the whole array.

EXAMPLE 2. DISCONNECTION POINTS WITH PARALLEL STRINGS
Note the two strings can face different orientations and nothing in the standards says they need to be within “arms reach”. However, when we use DPs, we need 1 set of MC4s per string

Conclusion
The new AS/NZS 5033:2021 can be quite challenging to interpret, with some unexpected changes emerging at the last minute. However, it also brings some welcome updates, such as the option to remove rooftop isolators and clearer signage requirements. The information provided above should assist solar electricians with the majority of these changes. Nonetheless, those familiar with the new 5033 standards will know that much of it is open to interpretation. If you think I’ve misunderstood any aspect or missed something important, please share your feedback in the comments below.
For a more in-depth understanding of the new standards, I highly recommend the AS/NZS 5033 crash video course by industry expert Glen Morris. It’s 6 hours long, costs $330, and is worth every penny.
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If you have any further questions, feedback, or inquiries about the changes to AS 5033, please feel free to reach out to us. Our team is here to assist you.
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