Solar Installations Technical Update 1
There are many challenges we face to make sure the systems we install are compliant with the rules and regulations.
Australia’s electricity network is rapidly changing, and everyone has a part to play in helping to ensure that the electricity supply continues to be reliable and safe for all.
Customers who have invested in Distributed Energy Resources (DER) like solar and batteries want to get the best outcomes and help keep the grid stable. As you may be aware settings on the inverters are required to be set according to your local distributor. These settings are typically the Volt-Watt and Volt-Var inputs.
These power quality settings may alter over time with your DNSP, so it’s best to check before you start commissioning and testing the job.
Solar installations must be completed in a safe way, making sure we maintain compliance and keep the auditors off our back. I’ve listed some common findings within the solar Audit program that requires some attention and consideration.
MC4 plugs not matting with the same make and manufacturer. This is easily fixed, but what has me more concerned is the actual crimping of the terminals. If you don’t have a proper MC4 crimper, make sure you get one. This is the weakest point and I’ve seen many installations with burnt MC4 plugs, just because of poor crimping.
Earthing panels and rails. Systems have been found to not have adequate earth (weeb) washers to penetrate the anodised aluminium rails and panels together, or the bonding from the switchboard was not made correctly. This shall be tested on each job, checking each panel and rail for earth continuity to the earth point at the switchboard, having a reading no greater than 0.5 ohms. Not only is this important for Equipotential bonding and safety. It is necessary for the inverter to detect if an earth fault is present within the solar array(s).
Another issue regarding replacement inverters. Make sure if your replacing an old isolated inverter with a new non-isolated (transformerless) inverter you will require the panels and rails to be earthed.(unless it was done prior) This would also require inspection, it’s not like for like and is of different topology, plus initiated further works to the earthing system of the associated array(s), and most likely replacement of DC isolators.
Conduits for DC use not glued or supported in roof spaces where access is available as per AS/NZS 3000:2018 clause 3.9.3. Gluing of conduits is important in maintaining the mechanical protection where the wiring system is likely to be disturbed, this includes supporting with suitable clips, saddles or ties. Gluing conduits for DC use, within wall cavities, ceiling spaces and under floors, will maintain the wiring enclosure to reduce the risk of short circuit. The DC wiring enclosures shall also be labelled with the word “SOLAR” at intervals not exceeding 2 m. (AS/NZS 5033:2014 Cl 126.96.36.199.2 & 5.3.1)
Labels always common in reports, but the one that appears to get noticed is the fire emergency one. The Voltage shall be the highest voltage present on the coldest day and the current (Isc) is the sum of the array currents. See section 5 in AS/NZS 5033:2014.
Glands shall be rated to IP56 when used outdoor and shall have the correct holes for the cables installed. Any unused holes shall be plugged using the manufacturers supplied plugs. Do not use short pieces of cable or silicone to plug up unused holes. It’s best to carry different combinations of the rubber grommet insert.
Residual current devices used for AC cables supplying inverters to provide cable protection as per AS/NZS 3000:2018 clause 188.8.131.52 (c) and AS/NZS 4777.1:2016 Cl 3.4.5. shall be rated to a maximum of 30mA. Generally, type “A or B”. Always making sure with the manufacturer of the inverter if suitable. If the manufacturers specify higher than 30mA to operate with their equipment. It would not comply with the requirements of AS/NZS 3000:2018 Cl 184.108.40.206 (c). Other forms of cable protection methods shall be provided as per the clause.
DC cables (array cables) in Concealed walls to meet the protection method requirements of AS/NZS 3000:2018 Cl 220.127.116.11. The only form you can implement is part (a) of the clause. Using an earthed metallic armouring, such as “Anaconda” for DC cables will not be enough. Clause (b) mentions “to operate a short circuit protective device under fault conditions”. This will not be available for those DC cables.
Required to have a minimum of WSX3 Rating.
See Appendix H for information on achieving WSX3 protection methods.
Note: where conductive mechanical protection is installed to meet the requirements of Cl 18.104.22.168(a). for the protection of double insulated conductors, earthing of the conductive mechanical protection need not be provided.
With the introduction of AS/NZS 5139:2019 a few issues are causing confusion. Mainly around the location requirements and what is associated equipment? As mentioned in the standard when installing a Pre-assembled integrated BESS or Pre-assembled battery system to the “Best Practice Guide”. (section 4 & 5 AS/NZS 5139:2019)
“No appliance or equipment not associated with the BESS or Pre-assembled battery system can be installed within the restricted zones”
Associated equipment would indicate any equipment that performs part of the generation equipment to enable the storage of power to the associated battery system. Commonly data cable is used between systems. This would indicate the inverter fits into this category if it is providing the renewable power from the solar panels to charge the associated batteries.
Do we consider an Inverter an appliance?
As per AS/NZS 3000:2018 Cl 1.4.9, an Appliance is:
“A consuming device, other than a lamp, in which electricity is converted into heat, motion, or any other form of energy, or is substantially changed in its electrical character”
An inverter does change substantially its electrical character from DC and converts it to AC. So yes, it could be considered an appliance.
In allowing inverters to be within the restricted zone. (Fig 1) You must also take into the clearances required for each piece of equipment according to the manufacturer’s recommendations.
The other issue would be, is it ok to have light switches and socket outlets within this restricted zone?
Light switches and socket outlets are defined as an accessory, so installing them in this area would be ok. But any appliance not associated will be required to be outside of the zone. (e.g. Ducted Vacuum system)
Fig 1 – Restricted zones for equipment not associated with the BESS or Pre-assembled battery system
Onsite technical support in solar
If you’re a new installer to the industry, it’s a great opportunity to make sure you’re doing everything according to Australian standards. The same for either new inspectors or inspectors wishing to do a refresher in the requirements of inspecting solar.
For further technical information, contact NECA 1300 361 099
Author: Louis Knopps - NECA Victoria Technical Manager