Waterlogged and isolated

Dramatic images of flood affected regions earlier this year gripped the nation. The devastating inundation spared few homes in a region that is otherwise known for its solar resources and popularity of rooftop PV.

BRISBANE-BASED SOLAR PV INSTALLER Steve Lee was

in the thick of things during the deluge that engulfed swathes of southeast Queensland and northern NSW during late February 2022. His rain gauge in the city’s western suburbs registered levels of 700ml over four days. The amount of rain was highly unusual and unsettling for all, he said.

“Had the ground been dry much of the water would have soaked in but the ground was already waterlogged so it ran off, straight to rivers and streams,” Steve said. The four days of rain saw water levels in the local dam rise from 55-60 per cent to 180 per cent, causing widespread inundation.

The region that is normally blessed with sunshine has one of nation’s highest uptakes of solar PV which meant thousands of inverters were destroyed during the floods, as illustrated on this page.

What to do

Forewarned is forearmed and PV system owners need to take necessary steps when heavy rain and likely flooding is forecast.

Basically you want to shut the system down, said Geoff Bragg of Sunman Solar who runs the Smart Energy Council Installer roadshows.

“In which case follow the shutdown procedure that’s written next to the inverter. There’ll be a sign there that indicates shut down and you know if it’s safe to do so. Also, if there are rooftop DC Isolators next to the solar panels, and it is safe to do so, turn them off. Only people experienced at getting on a roof should do this, and never get on a wet roof. If there are any doubts, get an industry professional.

“I’ve seen worrying pictures of people sheltering on a roof waiting to be rescued during a flood, right next to a solar array. Always be careful around solar panels as they contain dangerous voltages, especially when there’s water everywhere.”

Today there are so many combinations of household energy systems, some with batteries, so there may be different shutdown procedures, Geoff said, noting too that new industry Standards do not require the DC isolator to be on the roof.

“There are many different system variations so you can’t just give a general statement to turn off the DC isolator because there might not be one. That is why it’s best to follow the shutdown procedure that’s written on that system.”

Where to for those with damaged systems?

When equipment is wrecked, the first port of call is the insurer, it’s not the problem of the inverter manufacturers, Steve Lee said. However in some cases manufacturers have kindly donated a new system, for example where insurance was absent and homeowners were in financial strife.

“Following the last flood, insurance premiums in flood prone regions were significantly bumped up, in many cases by 20 per cent, which made it unaffordable for some,” Steve said.

PV systems are generally written off once submerged, they are not designed for that, he said.

“Though they have a high water rating you don’t expect the junction boxes to be submerged and suffer water ingress,” Steve said.

“PV panels form part of the building insurance (rather than contents) and I tell people to specify replacement for the full value, that is taking into account the government grants.”

He concluded by commenting on the frequency of the ‘highly unusual once-in-one-hundred year events’ that now occur every few years.

“I accept that weather patterns have always been cyclical, but what we are doing is not helping, we need to address wider factors relating to the causes of climate catastrophes which means tackling emissions.”

Most mains switchboards and inverters prominently feature a notice of shutdown procedures which are reasonably straight forward and as depicted here

IMAGE: NICOLA CARD