Excerpt from AS5033, the solar array standard.
As part of an ongoing series, I’d like to touch on some important points for maintaining solar.
I’ve worked for all sorts of employers: but in all my years, I think I only ever met one bloke who did truly preventative maintenance — keeping his kit running smoothly, and his employees and customers safe. Please bear with me while I pay tribute…
Greg Harris ran a charter service with coaches and a fleet of school buses. He insisted on teaching his drivers how to change tyres or even suspension parts on the side of the highway because Harris Coaches always got you home.
His phone manner was unique:
“Harris Gawler here! I’m sending you my alternator/starter motor/home rainwater pump.”
“What’s wrong with it Greg?”
“Nothing. Just wants a service. By next week, thanks”
The unit in question would be covered in paint pen; scrawled details of date, cost, and mileage of the last overhaul. Sometimes he’d run out of space to write the successive service histories.
Greg was a joy to work for. Nothing he presented was filthy, seized, or broken. It might need seals and bearings, but in good time, not as a screaming emergency.
The point is, his gear worked perfectly, and he enjoyed trolling the government inspectors who’d try to put his buses off the road for being too old.
When it comes to solar arrays, we could learn a little something from Greg. He kept the show on the road by taking maintenance seriously, and making time for regular inspections.
In solar, that could mean preventing serious safety issues. Here’s how.
A Harris bus: 40+ years old in this image and still motoring.
Regular Servicing Pays Dividends
As a licensed electrician, I’m obliged to mention that you should have your solar power system inspected and serviced every five years.
However, judging by the comments sections of previous articles, the sceptics will moan that I’m ‘just saying that’, as part of the Confederated Union of Simple Servile Slackers (which, they tell me, is a government-endorsed protectionist racket).
Of course, being CUSSSed for promoting safety and preventing house fires does tend to make your eyes roll.
Beyond that, regular servicing also ensures you’re up to date with regulatory requirements.
What Are Inspectors Looking For Anyway?
From a DNSP1 perspective, the most important part of an inspection is turning the mains off and making sure the inverter shuts itself down.
Inverters must not run as an island, because in the event of an outage or service work, nobody wants your solar power system to electrocute a line worker outside the property.
Keeping An Eye On RTIs
The most troublesome part of any solar power system, by far, is the DC Roof Top Isolator (RTI)2.
Because they start fires.
Once mandated as ‘safety requirement’, RTIs were a stupid idea introduced for spurious reasons (supposedly to isolate solar panels in the event of a fire).
After ten years of incorrect wiring, poor installation and water ingress (which various rule revisions failed to fix), RTIs had caused thousands of needless faults and hundreds of fires. Eventually, these switch disconnect devices were written out of the standards3.
Older systems can also have DC isolators at the inverter, which fill with condensation from the attached conduit.
The main driver for getting rid of them wasn’t the solar industry’s hatred, or electricians’ and inverter makers’ protests (from 19 years ago!) What finally drove the standards committee to delete them was complaints from firefighters themselves.
Those RTIs that remain are the weakest link. They need careful examination and, wherever possible, I suggest removing them.
In later years isolators had to have metal shades, not that this example does much.
If you have an RTI, the best way for your electrician to check it, and the panels themselves, is to run a short-circuit test on a sunny day and observe with a thermal camera. Poor connections, blown diodes, broken cells and corroded isolators will show up much more readily, because they run hot.
Bear in mind, just opening the door, or unscrewing the cover of an RTI for a look inside, can compromise it. If the plastic housing is warped, or the gaskets are perished and falling apart, it’ll need to be bogged up with silicone, replaced completely… or better still deleted on general principle.
That was an RTI, and yes it has burnt through the roofing iron.
Bogged up with silicone, this was never installed correctly anyway.
A Pragmatic Approach To RTIs
Many electricians will take a common-sense approach and replace the RTI with a simple pair of MC4 plugs and a label, like we used to do 15 years ago. Technically, the rest of the DC wiring needs to be brought up to current standards with new cable, conduit, more labels and specific routing through the roof.
Personally, I would settle for removing the RTI liability and installing an appropriate roof plan in the switchboard.
Technically, if you have an RTI replaced with a disconnection point, the DC wiring through the roof must not cross the ceiling. It has to adhere to this diagram.
Green under the glass is a sure sign of problems and will usually trip an earth leakage alarm on the inverter.
Earth Fault Alarms
Checking for earth leakage faults should also form part of an inspection, although a one-off formal test with an instrument doesn’t tell you much about how it’s performing over time.
Many people don’t realise an effective earth fault alarm is a legal requirement. So if your monitoring isn’t set up for any reason, advise your installer that you want a service and a savvy technician, who can make the connections work and explain how to interpret the information.
“…will be noticed” is the key phrase here.
Network Rules Oblige You To Have Your System Inspected
When SA Power Networks (SAPN) introduced the small embedded generator agreement, they condensed about nine pages of fine print into two.
The document outlined that if your solar equipment damages their poles or wires, you are obliged to buy SAPN a new electricity network. This blackmail contract also mandates five-yearly inspections by a qualified electrician.
Just because I have never seen the rule enforced doesn’t mean it’s not a good idea, to prevent that kind of damage from coming about. It’s certainly on the books:
Clause 5.5: Your ongoing responsibilities while your small generator remains connected
5.5(c): ensure the small generator is inspected and maintained by an appropriately qualified person:
(i) within at least 5 years after the date of its installation; and
(ii) within at least 5 years after each previous inspect.
It’s Good Sense To Work To Warranty
A good solar company should offer a five-year warranty on the installation works, in my opinion. This ties in with most decent inverters having five-year, 5+5, or ten-year warranties.
Either way, it’s a good idea to have your solar inspected before your warranty runs out, to ensure you can claim for any issues while it’s still valid.
Help Yourself With Basic Hygiene
Keeping things clean and tidy will ensure you don’t cause more problems for yourself between inspections, and will boost your chances of passing with flying colours.
But, statistically speaking, blokes in their 60s don’t bounce, so I don’t highly recommend climbing on the roof yourself. A handyperson who cleans gutters can also clean under arrays and check for dangling wires.
With a hose and a broom, they can clean the panels too. Just make sure nobody walks on the glass.
Dirt produces heat when soiled cells are shaded.
Monitor The Situation
I have an old mate who has kept a handwritten logbook tracking his solar yield for more than 12 years now. If we can ever get him to type it into a spreadsheet, he’ll have a brilliant view of the system’s performance over time.
These days, there’s a much better app for that. If your solar system doesn’t have one then I recommend a Catchpower Relay, or try Solar Analytics to measure what’s going on, and to access the tools to optimise your behaviour. A service such as Bill Hero4 can also be really helpful, in terms of selecting an energy retailer.
Monitoring might even expose a drop in performance that can be claimed under a panel warranty.
Equally, a big dump of hail can ruin an array without breaking the glass, so a sudden drop in performance can mean an insurance claim for storm damage.
Regular Inspections Prevent Future Pain
I know arranging regular inspections can feel like the nanny state gone mad, especially when all inspectors seem to do is remove a few leaves, tick a few boxes and walk away.
But inspections can also uncover small problems before they become big problems, saving you a headache (and a hefty bill from your energy retailer) in the future.
If you only consider the damage a faulty RTI can do, the maintenance required to keep tabs on it — and remove it if and when necessary — is easily worth it.
Call me an agent of the nanny state if you must, just remember that an inspection will cost less than the excess on your insurance.
Footnotes
- Distribution Network Service Provider — one of the 17 poles and wires authorities in Australia. ↩
- Except AC microinverters. ↩
- Some installations with shallow roofs can still require RTIs. ↩
- Full disclosure, SolarQuotes gets a small kickback through this link ↩
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