What's the fire risk of PV panels? What's the fire risk of rapid shutdown?

[brycenesbitt]

https://solargrade.io/2023/05/25/pv-system-fires-and-rapid-shutdown-devices-a-case-study-in-unintended-consequences/

https://solarbuildermag.com/featured/rapid-shutdown-connectors-supply-chain-leave-few-good-options-for-safe-pv-system-design/

March 27, 2023


NEC 2014 introduced the first rapid shutdown requirements for PV systems. The updated code aimed to eliminate the risk of first responders encountering DC voltage from PV systems. Here are the details:

Largely as a response to NEC 2017, manufacturers developed the rapid shutdown device, a new type of PV system component that enables installers to deploy string inverters and fulfill NEC requirements. Unlike power optimizers and microinverters, RSDs are module-level power electronics with a single purpose: to quickly de-energize PV modules.

Based on our professional field observations, we believe that the rapid shutdown requirements for PV systems in the U.S. National Electric Code (NEC) have backfired.

[solar pete]

Yeah, I think it was always stupid idea too, we don't even put DC isolators on the roof here anymore in Oz , you can have a DC isolator at the inverter a much better idea

[Mike 134]

https://solargrade.io/2023/05/25/pv-...-consequences/

https://solarbuildermag.com/featured/rapid-shutdown-connectors-supply-chain-leave-few-good-options-for-safe-pv-system-design/

March 27, 2023


NEC 2014 introduced the first rapid shutdown requirements for PV systems. The updated code aimed to eliminate the risk of first responders encountering DC voltage from PV systems. Here are the details:

Largely as a response to NEC 2017, manufacturers developed the rapid shutdown device, a new type of PV system component that enables installers to deploy string inverters and fulfill NEC requirements. Unlike power optimizers and microinverters, RSDs are module-level power electronics with a single purpose: to quickly de-energize PV modules.

Based on our professional field observations, we believe that the rapid shutdown requirements for PV systems in the U.S. National Electric Code (NEC) have backfired.

And what profession would that be? Size of your data base?

You did notice the VERY FIRST sentence on your link said solar fires are RARE.

[Mike 134]

I just checked there are 47,185 members on this site. For the sake of argument lets say 50% have solar. How many have posted about having a fire? Just food for thought.

[brycenesbitt]

And what profession would that be? Size of your data base?

According to the authors they are experts in post-failure analysis of commercial solar systems.

"We analyzed more than 60,000 PV system health datapoints to find out. Read the SolarGrade PV Health Report for a comprehensive, ground-up assessment of PV safety and reliability in the U.S. and Puerto Rico."

"The HelioVolta team has assessed the health of hundreds of distributed generation (DG)
PV systems as an independent provider of third-party inspection and quality control
services. Our clients span Fortune 50 companies, asset owner-operators, investment
firms, and insurers."

[brycenesbitt]

A graph from the paper
Capture.JPG

[Calsun]

When my solar panel installation was done in 2012 the county required an inspection and sign off by the fire department. They had two concerns about any panels on a roof. First was that a fire fighter could be up on the roof and making the holes which is a common practice. Second was that there was a power shutoff switch for the panels' output. The requirement for the first aspect limited how many panels I could put on the roof and reduced my system's total output by about 30 percent.

In areas where this is not enforced I have seen cutoff switches that could only be reached with the use of a ladder. There does need to be an inspection to verify that the installer has not done something stupid.