Hi Brad;
I think that remotely tripping the inverter might work with Outback, but
definitely not with Magnum. (I checked with them today) Also, if the
battery cables are more than 5 ft long, the rapid disconnect /might/
have to be closer to the batteries. (/690.12 ...shall apply only to PV
system conductors more than 5 ft in length inside the building...)
/As for inverter and overall system reliability? I'm afraid that//is
going 'Rapidly' down hill.// Decades//of experience says that the more
gizmos and automatic controls you add, the more chances you have for
something to go wrong. The Birdhouse system defaults to/'off' /with any
communications problems, so one CAT 5 cable has a nick in it, and the
entire system crashes.//With all this emphasis on safety, we also need
to be thinking about our customers living alone in cold, remote locations./
/Perhaps an emergency disconnect for the emergency disconnect?
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 3/15/2016 5:45 PM, Bradley Bassett wrote:
I've been promoting the use of the remote on/off terminals that are
available in most inverters, which can be connected to the AUX in the
Birdhouse. For a very minimum effort and cost, the inverter AC output
would be shutdown when the rapid shutdown is activated. I think using
the remote on/off terminals seems a lot cleaner way to do this than
disconnecting the battery cables. And there is the possibility that
disconnecting the battery from a fully loaded inverter may damage the
inverter, do we really want to risk that whenever we test the RSD
system? None of the current inverter mfg will say that this will do
any damage, but they don't seem very convinced to me. I remember a
decade ago when they did say there could be an issue. I'm not sure how
much different inverters are now than then.
Brad
AEE Solar
On Tue, Mar 15, 2016 at 12:48 PM, Patrick Shortell
<pshorte...@gmail.com <mailto:pshorte...@gmail.com>> wrote:
Dear List,
Maybe it's an over simplistic opinion, but shouldnt all sources be
disconnected rapidly in an emergency situation.
We can always do better than what the code requires. I get
frustrated when people go to the book, (and try to hide behind the
text). instead of thinking through real life scenarios.
There are simple ways to work around these issues.
I find when something is questionable, Ill call the AHJ and get
his approval First.
What would I do in my own house?
What if someone thought all the power was off when they dragged a
hoseline into my basement.
My two cents
Pat
On Tue, Mar 15, 2016 at 1:10 PM, <billbroo...@sbcglobal.net
<mailto:billbroo...@sbcglobal.net>> wrote:
Ray,
I guess I have to step in after that acknowledgement. PV
system circuit is a
self-defined term and therefore cannot be defined unless you
are going to
develop a meaning that is different from the self-definition.
It means ANY
circuit in a PV system. This includes battery and stand-alone
circuits in
the 2014 NEC.
The language of the 2014 NEC was a compromise between the fire
service and
the PV industry. Originally, the language required
essentially module-level
shutdown. I raised the concern with the PV industry to get
them involved
since most were not paying attention at the time. This
language was
developed and intended to cover all circuits in a PV system.
In the 2014
NEC, batteries are part of a PV system and therefore fall
under this
requirement.
In the 2017 NEC, we were very careful to carve out all
batteries and loads,
that were previously part of PV systems, and place them in
their own
articles. Don't shoot the messenger on this one and don't
think for a minute
that I alone made this requirement or am alone in interpreting
it in this
way. I did author this compromise with other representatives
of the PV
industry so I think I know what the intent was.
It is understandably difficult for battery systems and I would
try to keep
battery circuits as short as possible. The 5-feet was intended
to match the
requirement of 690.71(H)--which is further evidence of the
intent of the
2014 NEC.
The 2017 NEC removes batteries from the requirement, but they
still cannot
backfeed the PV array. Energy storage systems (Article 706)
will have their
own requirements in time--that is guaranteed.
Bill.
-----Original Message-----
From: RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>] On
Behalf Of Ray Walters
Sent: Tuesday, March 15, 2016 9:02 AM
To: RE-wrenches <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
Subject: [RE-wrenches] Rapid Shutdown
Greetings Esteemed Wrenches:
I've just heard back from our inspector here in Colorado, and
we are still
being required to disconnect the batteries under 690.12. No
where in 690.12
are batteries mentioned, nor in the appropriate 690.71 section
that deals
with batteries. The entire reasoning behind this is based on
a single
article written by a single person: Bill Brooks. I have
contacted both
Outback and Magnum on this issue, and their engineers are
unaware that rapid
shutdown applies.
My interpretation is that I could install an inverter and
battery system
that was charged from a generator, and we would not need any
rapid shutdown
at all. But according to Bill, as soon as I put a single
solar module into
the system, suddenly the entire system becomes PV? The problem
lies with the
term 'PV System circuit' used in 690.12. 690.2 Defines 'PV Output
circuit', and 'PV source circuit', but there is no 'PV system
circuit'
defined. 690.12 therefore uses an undefined term.
Our design uses 2 inverters, so if we used Midnite's E panel
with their
remote trip breakers, the 2nd inverter would be more than 5 ft
from the
batteries. If we used Magnum or Outback DC disconnects (that
would comply
with the 5 ft rule specified in 690.71) they don't offer
remote trip.
We have a Midnite Rapid disconnect Combiner on the roof with
the Birdhouse,
so we are complying with 690.12, it should not be applied to
batteries
though.
Thanks,
--
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760 <tel:303%20505-8760>
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--
Patrick A. Shortell
/Licensed Master Electrician/
/Certified Solar Installer/
71 Oregon Street
Long Beach N.Y. 11561
cell: 516-477-0221 <tel:516-477-0221>
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