Solar Installations Following AS/NZS 3001.2:2022 Standard

AS/NZS 3001.2:2022 defines requirements for connectable electrical installations. This whitepaper will give guidance for achieving compliance with the latest standard. This is guidance only and the recommendations do not guarantee compliance of your system. It is recommended that you read and understand AS/NZS 3001.2:2022 in full to ensure compliance of your system. AS/NZS 5033:2021 is recommended reading for further guidance. This whitepaper does not cover compliance with all aspects of AS/NZS 3001.2:2022 and focuses on the aspects relevant for installations using solar (Photovoltaic) power. 

This guide does not apply to REDARC portable solar panels including solar blankets, folding solar panels, and amorphous solar blankets.

Manufacturers specify Panel ratings at Standard Testing Conditions (STC). It is required to consider the maximum currents and voltages under different temperatures and sunlight intensity during operation. AS/NZS 3001.2:2022 refers to AS/NZS 5033:2021 which defines the calculations for maximum values. To account for variations: 

1. Where the lowest operating temperature is -10°C, multiply manufacturer specified (STC) open circuit voltages by 1.15. 
2. Where the lowest operating temperature is -40°C, multiply manufacturer specified (STC) open circuit voltages by 1.25. 
3. Multiply manufacturer specified (STC) short circuit currents by 1.25. 

For compliance, the Photovoltaic (PV) Array must not produce a DC voltage over 120V. Note that the REDARC range of Solar Regulators including the Manager30 and BCDC have a maximum input voltage of 32.0V. This means most panels should be connected in parallel and not in series to avoid exceeding the solar input voltage limit. 

The PV Array must be connected to a regulator which is used to charge the battery. The REDARC range of Solar Regulators including the Manager30 and BCDC will ensure compliance with this requirement.

All components of the wiring system must be specifically designed for use with DC PV Systems. The wiring system includes fuses, wire, and connectors.  

PV1-F 4mm²/6mm² cable, MC4 connectors, MC4 junction connectors, MC4 junction wiring looms, and in-line MC4 fuses are all suitable for this purpose. 

A String is one or more Panels connected in series. This means:

1. 3 Panels connected in parallel are 3 Strings  
2. 3 Panels connected in series are 1 String

If you have 3 or more Strings in your Array the following three requirements apply:

1. Overcurrent protection devices must be installed on the positive (+) conductor of each String.
2. Overcurrent protection devices must be installed as close as practical to the point where the Strings are connected in parallel.
3. Overcurrent protection devices must be rated at no more than 1.5 times the “String short circuit current capacity between Strings”. This is the total current in a short-circuited String due to the generation of all other Strings. 

We recommend that these devices are rated between 1.5 and 2.0 times the short circuit current rating of the String it is installed on. This will guarantee compliance with this requirement and provide effective fault protection. 

The following requirement applies for all PV Array installations, even if there are fewer than 3 Strings e.g. a single String (which includes an installation with a single PV Panel).

The wiring between the Array and the regulator must be suitably protected from overcurrent. The Array wiring is the wiring that is connected to the regulator once all the Strings have been connected in parallel.  

This wiring can be subjected to the sum of short circuit currents from all parallel Strings in the system e.g. if the regulator has a short circuit fault. To achieve compliance, it can be protected in any one of the following methods:

1. The rating of the wiring is greater than the short circuit current potential of the Array i.e. the current rating of the wiring is greater than the maximum current the Array could generate under short circuit conditions.
   
   OR
2. The rating of the wiring is greater than the sum of individual overcurrent devices on each String e.g. if you had three Strings and each had a 15A fuse, the wiring would be considered protected if the wiring is rated higher than 45A.
   
   OR
3. A separate overcurrent device with a suitable rating can be used to protect the Array wiring. E.g. 50A Array wiring may be protected with a separate fuse with an appropriate rating. 

There are also general requirements that all overcurrent protection devices must have appropriate current and voltage ratings for their application. This means that any calculation of fuse rating must also consider its effectiveness at protecting the wiring it is connected to. Overcurrent protection devices must also be of appropriate construction for their operating environment e.g. resistance to corrosion.  

It is a specific requirement that all fuses used for the PV system must not be rated less than IP2X in any configuration, including when the fusible link is removed (if applicable). Using an MC4 inline fuse complies with this requirement. 

Photovoltaic Arrays should be created by connecting identical panels together. Panels with different voltage and current ratings should not be connected to form an Array.  

We recommend a fuse in series with each String rated at 1.5 to 2.0 times the nominal short circuit current rating of the String (i.e. the manufacturer specified rating at STC). A rating between these values will always be compliant and provides effective protection under fault conditions. For the SMSP1180 with an ISC of 9.7A at STC we would recommend a fuse rating of 15A or 20A. Circulating current faults can occur with 2 strings, but will not be dangerous nor able to be protected against with the use of a fuse.

A rating lower than 1.5 times ISC risks nuisance tripping of the fuse in bright sunny conditions.  

A rating higher than 2.0 times ISC may not trip under fault conditions and subject the panel to excessive fault currents which can pose a safety risk.  

NOTE: The fuse must still be sized appropriately for the wiring system, which includes connectors.

This system does not have facility to connect to an external low voltage AC supply system (e.g. shore power) and therefore is not required to comply with AS3001.2:2022

NOTE: The system may have AC Mains power, as from an inverter, but is not allowed to be connected to an external AC power supply. 

1. The panels will not produce a voltage greater than 120V for compliance. NOTE: The Manager30 has a maximum input voltage of 32.0V.
2. The connectors are MC4 type, specifically designed for use in DC Photovoltaic (PV) systems.
3. The wiring is double-insulated 4mm² PV1-F wire, specifically designed for use in DC PV systems. 6mm² PV1-F can be used to reduce losses on long cable runs. NOTE: extension cables as shown are typically required for ease of installation but are not required for compliance.  
4. The fuses are MC4 type, specifically designed for use in DC PV systems.
   The fuses are located as close as practical to the junction of the Strings.
   The fuses are rated at 15A:
   
   1. This is suitable to protect the String wiring.
   2. This is recommended to be between 1.5 and 2.0 times the rated short circuit current at Standard Test Conditions (STC)
   3. This is below the limit of 1.5 times the maximum short circuit current experienced by a short-circuited string
      i.e. 1.5 × 2 panels × 9.7A × 1.25 = 36.4A  -  This includes the 1.25 factor to calculate maximum short circuit current.
5. The wiring junction uses MC4 type splitters, specifically designed for use in DC PV systems.
6. The Array wiring uses 50A 4mm2 PV1-F wire which has a rating higher than the total short circuit current of the Array i.e. 36.4A. This is considered sufficient protection for compliance requirements.
7. A circuit breaker is not required since the Array wiring is rated for the maximum short circuit fault current. It is recommended to include a switching style circuit breaker or an appropriate isolating switch for ease of maintenance and repair due to its ability to isolate the Array.  
8. Optional: Adding a second array (in parallel) will increase the power in low-light conditions.