Clearly, rapid shutdown increases cost and reduces reliability. Given
the excellent safety record of PV, prior to rapid shutdown being
required, it is unnecessary. The few anecdotal incidents of PV fires
were not enough to justify the requirement, especially on smaller
systems.
According to a friend who worked for a local installation company that
went under, a big part of the reason for their failure was the chronic
replacement of microinverters and optimizers.
What steps can be taken to create some balance in the rapid shutdown
requirements that are in the NEC?
---
On 2020-04-29 07:27, Sky Sims wrote:
So far rapid shutdown has been a nightmare. It's added a lot of cost for no measurable benefit.
Using always off devices like midnight solar and Tigo makes it impossible to test open circuit voltages. Which opens the door to tons of problems when commissioning systems.
Also we've been trying out midnight Solar's product and have had an absurd failure rate. Which means lots of truck rolls and troubleshooting and system downtime. They send replacement product but they aren't paying for the lost weeks of productivity.
We have Tigo product in hand and are deciding which project to try it on. But our big concern about using it is not only the inability to confirm open circuit voltage of the strings but also the way panels bypass if the device doesn't allow the panel to connect properly. Both of these features are a recipe for problems and potential troubleshooting nightmares. The warranty from Tigo doesn't cover our expense if the product fails. And that's really what our reservations about the product boil down to right now. If we're on a job with 50 units and one fails, the contractor or the homeowner will be the ones eating the expense of finding it and replacing it. There has to be a better option.
Sky Sims
Https://EcologicalSystems.biz
On Apr 28, 2020, at 7:46 PM, Corey Shalanski <coreso...@gmail.com> wrote:
Now that 690.12 of the _NEC_ 2017 has been in effect for several years, I am curious how designers and installers are meeting the associated requirements with string inverter-based systems (*not* considering microinverters or DC optimizers). I am generally a fan of the KISS principle, and as best I can determine the _Tigo_ TS4-F device is one of the simplest options currently available on the market. What are others finding?
I'd love to hear about favored options for complying with rapid shutdown. Any success stories? or better yet, any early failures?
--
Corey Shalanski
Jah Light Solar
Portland, Jamaica _______________________________________________
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