Warehouse operator takes US rooftop solar offline after six fires or arc-flash events

What happened

Between April 2020 and June 2021, a warehouse operator had six fires or arc-flash events at rooftop solar on 47 North American sites. The first, on 14 April 2020, was a three-alarm fire at a fulfilment centre in Fresno that damaged 220 modules. About fourteen months later a two-alarm fire at Perryville, Maryland, drew in around sixty firefighters. By June 2021 every US rooftop array had been taken offline. An outside inspection then reported one critical finding and 259 major findings. That audit covered rooftops in the United States, Asia Pacific and Europe, the Middle East and Africa, not only the 47 North American sites.

Contributing factors

The inspection reported mismatched connectors, connectors installed incorrectly, poor wire management and water inside inverters. The source says none of these was a panel defect. It does not identify the operator.

Lessons learned

1. Mating connectors should be of the same type and brand, or listed and identified for intermatability, before they are joined.
2. Large rooftop arrays contain many handmade joints that can loosen with heat, weather and poor wire management, so connectors, leads and inverters need periodic inspection.
3. Water inside inverters and leads left free to rub on racking should be treated as fire risks, not only as losses of generation.

More lessons on maintenance, inspection and ageing assets, weather and external hazards, from every incident on the register.

Not yet known

• Which factors applied to each of the six events
• Operator name
• Equipment model and age

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Source

ecoportal.net