Hi Jerry;
This isn't about us not being willing to learn the tech. All of us are
constantly learning about new code changes, new inverters, and solar
modules that change specs every few months. We are voluntarily adopting
new technology (like Lithium Ion batteries) when that technology is cost
effective and reliable.
To continue your smart phone analogy, the current situation is like
forcing people in the country to give up their hard lines, when their is
only spotty 3G service available in their area. Its not that we are
Luddites; the equipment is still not quite ready for prime time.
Having some basic exemptions for small, lower voltage systems off grid
is not unreasonable.
Ray Walters
Remote Solar
303 505-8760
On 4/30/20 2:33 AM, Jerry Shafer wrote:
Wrenches
We are taking two very different issues and mixing them together. RSD
and Arc-fault are different, arc fault will and does prevent fires,
RSD was brought out of the need to vent a roof that even with the
meter pulled have 500 volts and resulted shocks to fire fighters by
cutting into roofs or nearby conduite. This is fact not conjecture.
Arc fault is a fire preventer but requires nothing on the roof when
using string level inverters. Now both RSD and arc-fault in off grid
increase the complexity but the new charge controllers fit the arc and
Tigo fixes the RSD issues.
I know everyone of you learned to use a smart phone and can now adapt
again to this new tech, we have to be leaders in this industry and not
well you know.
Jerry
NABCEP PV Inspector.
Been in this industry since 1978
On Wed, Apr 29, 2020, 6:57 PM Jay <jay.pe...@gmail.com
<mailto:jay.pe...@gmail.com>> wrote:
Hi Drake
I will disagree, there have been many roof top fires.
But regardless we have to do these new regulations and I for one
welcome the safety.
The main issue is accessing the faulty/suspect component under the
module possibly requiring removing multiple modules, a slow and
expensive process.
My technique is to install the MLPE at the edges of the array,
using wire extensions. That way at most I have to remove a single
module. And Im working on a drop bracket which would allow better
cooling and easier access without module removal to the MLPE,
greatly reducing time to swap.
Jay
Peltz Power.
On Apr 29, 2020, at 7:59 AM, drake.chamber...@redwoodalliance.org
<mailto:drake.chamber...@redwoodalliance.org> wrote:
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 <mailto: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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