Because commercial solar is an important investment – not only financially but in the future of your business – it makes sense that you’d want to keep your panels in optimal condition. After all, when your solar is working hard for you, it makes a big difference to your energy bills.

While a solar provider can monitor your panels and address any issues before they become larger problems, it may be helpful to know how different faults affect your panels and what you can do about them.

1. DC Isolator Failure 

Why?

DC isolators were required on the roof of every solar system, as specified by a previous Australian standard. Whilst this is not the case anymore, there are still many systems in the field with isolators on the roof. DC isolators endure the full brunt of the elements which can lead to their failure.

There are cheap isolators available on the market, which are lower quality and are likely to fail sooner than their rated lifetime. Additionally, many rooftop isolators are installed without covers, meaning that they will degrade very quickly in sunlight and are vulnerable to water ingress. We recommend choosing high-quality DC isolators and always using a cover.

A DC isolator failure can be a major fire hazard, as once it is exposed electrically, it can be prone to a short circuit that can result in the isolator burning up.

How do we mitigate this?

1. Most isolators are rated to last 7-8 years, but we recommend replacing isolators every 5 years to ensure that your solar system is safe.
2. Use of quality isolators.
3. Isolators need to be inspected regularly, even if they are of good quality. Electricians should be checking for any potential signs of vulnerability, penetrations or water ingress. It is best to find it before the damage is done.

2. Earth Faults

Why?

An earth fault occurs when the insulation resistance of a circuit is compromised. This means that electrical current leaks out of the cables or electrical components (the equivalent of a leaking pipe in your house). Earth faults are often caused by rainwater or dew getting into the solar panels, DC isolators or other components, or installation errors where sharp edges cut into the cable sheathing.

Your inverter is constantly monitoring for earth faults and is designed to turn itself off and stop producing power when it detects one. In fact, this is a legal requirement which is necessary to prevent electrical hazards and fires, and your inverter will usually turn itself back on when the earth fault is gone (e.g. when the water dries up or when a cable is replaced after being damaged).

How do we mitigate this?

The risk of earth faults can be reduced with good quality components and installation practices. Smart Commercial Solar work with experienced installers who ensure cables are laid neatly and protected with conduits or cable trays, as well as test for earth faults as part of system commissioning.

In short, we use high-quality installers, panels, isolators, and other materials to ensure the system's longevity and to prevent earth faults from occurring.

Solar Monitoring will also ensure that any minor earth faults are picked up before they become larger issues, and can be rectified more quickly.

3. Grid Faults

Why?

The standard grid voltage in Australia is 230V AC, and all of your electrical appliances are built to operate at or near this voltage. However, the grid voltage can vary slightly depending on the electricity supply and demand in the region.

A solar system's inverters are designed to operate in an allowable voltage range of 216-253V. When the grid voltage is outside this range, your solar inverter will be disconnected from the grid and won't supply you with solar power.

High voltage is becoming quite a common occurrence as more solar is added to the grid, and often the network service providers are not aware of local voltage issues.

How can we mitigate this?

 At Smart Commercial Solar, we monitor the grid voltage at our customers' sites. If your voltage starts approaching the upper limit of 253V, we will contact your network and follow up a service case to make sure that the network provider will rectify this issue.

Another alternative is to add in voltage optimisation at your site which is meant to artificially lower the voltage to ensure that they are operating within the allowable limits.

4. Nuisance/Thermal Trips

Why?

All electrical components (circuit breakers, fuses) are rated for a certain level of thermal exposure. When components are exposed to prolonged periods of heat, they derate and will trip at a much lower current threshold. This means that on extremely hot days, components tend to trip which will mean that your solar inverters may switch off.

How can we mitigate this?

Using quality components will ensure they have a higher tolerance to heat and will not derate as much due to thermal overload.

Systems should be designed to compensate for heat to ensure that components and cabling are not over-generating heat from being undersized or minimally sized.

We check that all our inverters are on in areas that experience days above 35 degrees. If inverters are consistently tripping on hot days there are a few things we can do to solve this problem:

1. Switchboard cooling: installing fans, extra ventilation or heat sinks.
2. Switchboard redesign: upgrading or spacing of switchboard components.

5. Hot Joints

Why?

A hot joint occurs when there are two electrical conductors that are not fully in contact. When this happens, a large amount of current passes through a small surface area causing the conductors to heat up. This can cause components to burn and sometimes catch on fire.

This generally occurs because electrical components expand when they are hot and contract when they get cold, causing the connections between electrical components to become loose.

How can we mitigate this?

The only way to prevent hot joints is through regular inspections, ensuring that all electrical connections are tight and taking thermal images to make sure that components are all within normal operating temperatures.

Take Home

As you can see, even though solar is considered a low-maintenance asset, there are a number of small faults that can arise through improper installation, parts or maintenance. At Smart Commercial Solar, our Service team actively monitors and maintains over 1,000 systems across Australia and The Pacific Islands.

To learn how we can help you to maximise the performance of your solar investment, get in touch with us today.

Get the latest news and find out what’s happening in the commercial solar space at Smart Insights.