Kirk,
I ran into a very similar problem with a system where the connectors were left
unmated for a period of time. Salts got into the connectors and whenever the
humidity was high, the salt would track current through the connector seals.
Replace all the connectors first before trying anything
Kirk,
The tables in Appendix C are just for reference. They are not part of the Code.
The only real part of the code is in chapter 9:
Table 1 Percent of Cross Section of Conduit and Tubing for
Conductors and Cables
Number of Conductors and/or Cables Cross-Sectional Area (%)
1
Jason,
It sounds like you want to get involved with the PV industry forum. We have
about 30+ active members this year so your input would be welcome.
I think your idea about organization needs to be informed about some details.
First of all, you need to read the new, very different, 705.12(
Kirk and All,
I just got back from PV America and one of the venders there had a new PV
Wire that was a completely different construction (not XLP). Their outer
jacket is a more UV resilient material.
There are also PV Wire with PVC jackets that are less resilient to UV than
XLP. Ask for details
een it seems like panels that degrade at 0.5%/year are
outliers on the low side.
Thoughts from other wrenches?
On Tue, Jun 3, 2014 at 11:59 PM, Bill Hoffer mailto:suneng...@gmail.com> > wrote:
Dana
Bill Brooks, passed on past data, ( correct me Bill if I am out of date
m: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Bill Hoffer
Sent: Tuesday, June 03, 2014 9:00 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Module Degradation - voltage or current?
Dana
Bill Brooks, passed on past data, ( correct me Bill if I am out of date
Read this article from SolarPro:
“Array Voltage Considerations”, SolarPro Magazine, October/November 2010, pp
68-78.
Bill.
From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf
Of Dana Brandt
Sent: Tuesday, June 03, 2014 3:42 PM
To: RE-wrenches
Subject: [RE-wrenc
-wrenches-boun...@lists.re-wrenches.org] On Behalf
Of Jay Peltz
Sent: Tuesday, May 27, 2014 11:32 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] 2014 NEC
Hi nick
Good to know, I was told this by bill brooks at a training a few months ago.
Jay
Sent from my iPhone
On May 27, 2014, at 9:00 AM
Kirk,
That is correct. Raceways are not rated for voltage. The key is whether the
conductor is intended to be installed in a raceway or not. Raceways are also
allowed to be used for physical protection only for direct buried cables and
exposed cables. The raceway is only required to prevent phy
Martin,
I agree that this would meet the requirement.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Martin Herzfeld
Sent: Friday, May 02, 2014 10:49 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Rapid shutdown for pol
dule(s) or panel(s) secured
by removable fasteners and connected by a flexible
wiring system.
This is not a change. Please help me understand the concern.
Bill Brooks.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R
James,
This product is probably much like Rain-X. While you could put it on PV
modules, it would require reapplication on a fairly regular basis to keep it
working. As you pointed out, I don’t think many, if any, module manufacturers
that would specifically warranty their product with Rain-X
Aaron,
An exterior utility service panel with an underground service lateral is not
considered in or on the building.
Keep the dc conductors off of the building and you will be fine with a
ground-mounted PV system. Don't bring them inside the building, and don't
run them along the exterior of th
nverters? Good, bad, or ugly?
Thanks,
Garrison
From: Bill Brooks [mailto:billbroo...@yahoo.com]
Sent: Friday, April 04, 2014 2:09 PM
To: 'RE-wrenches'; 'Garrison Riegel'
Subject: RE: [RE-wrenches] Three Inverters, One Disconnect?
Don and Garrison,
The word “dedicated
Don and Garrison,
The word “dedicated” means “no loads”. That is why, the way the code is written
today, you cannot plug a microinverter into a wall outlet. There is no limit to
the number of inverters that can be placed on a single breaker. The limitation
for inverters, is the maximum overcu
Dave and Troy,
I don't think JW had his facts correct on this. The standard test for a
busbar is to place the highest allowable breakers directly below the main
breaker to test for overtemperature of the busbar. With the requirement for
Article 220 compliance of the panel, a panel that actually
re else in the panel
that changes this?
Glenn
From: re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Wednesday, March 12, 2014 7:24 PM
To: 'RE-wrenc
William,
Go to http://www.associatedsoftwaresales.com/home.php . They do a 48-month
lease of 2013 AutoCAD LT for $325. If you really need AutoCAD, there is no
cheaper route that I know of.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wre
Glenn,
The vast majority of service equipment for residences is rated 10k AIC.
Although utilities may say they have some residential services that exceed 10k
short circuit availability, it is still pretty rare.
Using single phase gear on a 3-phase commercial installation is a different
sto
required of the building. At least that's the interpretation I
initially got from my local building and safety office. They've been sitting
on my plans for two weeks so far. When they turn them around, I may have
more to talk about.
/wk
William Korthof
714.875.3576
Sustainable Solution
Yes Peter,
It is called the 2012 International Fire Code. The California guidelines
were turned into code in 2012. There is an explanation document I wrote
available online at:
http://solarabcs.org//about/publications/reports/fireguideline/index.html
For those states that are using NFPA 1 as th
WK, Marco, and William,
Agreed that 208V versus 240V is not an issue for 240V single phase loads.
Phase angle is not an issue for single phase loads--same reason that a
single-phase inverter can work with 208/240/277V. In the case of the
inverter, typically it is simply a winding count difference
Mark,
You should know better than anyone else that you can't corner the sun
market. If you read the reports you will find that your deepest fears are
unfounded.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Fry
Kirk,
There is no standard diameter for PV Wire so Chapter 9 table 1 must be used.
By the way, Table 1 is the code and the table in Annex C are not officially
the code. They are simply informational based on the standard nominal
diameters of various conductors. Many conductors have non-standard
William and John,
A "320" as it is affectionately called is a 400-amp panel with a 320-amp
continuous duty. This is identical to two 200-amp panels that each has a
160-amp continuous duty-that we put 40-amp breakers into on a routine basis.
The "busbars" are rated for 200-amps each, just like a
Jeffrey and Ray,
Batteries can off-gas hydrogen-sulfide gas when under heavy charge or
overcharge. It is the nasty rotten egg smelling gas. Definitely not to be
inhaled since when it hits your lungs it turns back into sulfuric acid.
To address Ray’s point, the new 690.12 regulation that has
Dan,
I believe you are referring to the Sedona fire when you talk of the
energized fence. I believe the fire department was in error when they
reported that the rooftop EMT energized the fence. It is pretty clear from a
review of the facts that the ac service drop burned free from the house and
William,
One way to think about this is that temperature correction is used based on
the location of the ambient temperature you are concerned about.
Mostly, we are worried about the very high temperature of conductors in a
sunlit raceway on a roof. This gives us very high temperatures and we
Frye
Sent: Tuesday, January 21, 2014 6:03 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown
OK. So I will have a high rate of acceptance if it buy an Tyco vacuum relay,
and mount it in a Hoffman enclosure, and then put it on my roof?
On 1/21/2014 5:45 PM, Bill Brooks
Brian,
The requirement is generic. A listed contactor can meet the requirement. A
standard is only necessary for products that want to be innovative in meeting
the 30V, 240VA. Killing all power is an option with existing listed equipment.
NEC 90.4 does not apply.
Bill.
From: re-wrenches
subject since it was a very far-reaching and potentially
confusing new requirement in the NEC. Thanks for your interest and let's
keep the constructive dialogue going on the subject. It is time to get
involved in the NEC update process again.
Bill Brooks.
From: re-wrenches-boun...@lists.re
delivers more than we could
ever use in just about 8 minutes. And it's wireless!"
~William McDonough
On Tue, Jan 14, 2014 at 10:47 PM, Bill Brooks mailto:billbroo...@yahoo.com> > wrote:
Andy,
How are you testing the ground impedance of the EGC?
Bill.
Fr
Andy,
How are you testing the ground impedance of the EGC?
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Andrew
Truitt
Sent: Tuesday, January 14, 2014 7:25 AM
To: RE-wrenches
Subject: [RE-wrenches] EGC ground impeda
Martin,
Regarding your reference to installations west of I-280 requiring Class A, I
did not find that in Palo Alto's materials. The City of Woodside fire
department was very involved in the CalFire Guidelines and I would not be
surprised if they implemented such a requirement. If you can find
ystem will result in a Class A
fire-rated roof-mounted PV system.
At least that's how I understood the presentation delivered by Christopher
Flueckinger from UL during the "Fire Safety" session at SPI in Chicago. I'm
sure Bill Brooks will chime in shortly and provide more clarit
nominal voltage. Generally, this
is not a problem since an inverter that does not act quickly enough will
damage itself.
Bill.
Bill Brooks, PE
Principal
Brooks Engineering
3949 Joslin Lane
Vacaville, CA 95688
707-332-0761 (office and mobile)
b...@brooksolar.com (email)
www.brooksolar.com
nding electrode for PV
arrays.
He used everything short of drum rolls to build anticipation for this part
of the presentation.
Having personally contributed a short piece on this subject for SolarPro
magazine along with Bill Brooks and John Wiles in 2008, I looked forward to
this discussion. Finally, m
not
helping at all. The trend has been to make it harder to protect wiring.
This trend will result in accidents. I think we should do better.
Sincerely,
William Miller
From: re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:r
William and David,
This particular problem goes away with arc fault detection. The longer we
wait to introduce arc fault detection into our systems, the more we will
have opportunities for news reports such as the one William brings forward.
Wire ties are not the problem. Could a wire tie cause
Kirpal,
I'm not aware of a 15-degree allowance for NEMA 3R. Others on this forum may
be more familiar. Bottom line, if the installation instructions do no
specifically allow for an angle, you have to assume that vertical is the
only allowable orientation.
The only rooftop disconnects that
Howie,
I think your electrician friend either misheard John or John was wrong. I
believe the truth is that AC cable (aluminum clad) would have to be listed
for dc. The NEC is specific about the grounding capabilities of the MC. I am
unaware of any specific dc or ac requirements that MC has. There
Marco,
Besides the good responses you have already received, 20-30kW, 480V machines
are really targeting larger installations that would be on facilities with
480V. I would generally not build a system with 480V inverters on a 208V
service. For large systems, there are large inverters runnin
William,
Just to add one more thing. I said that the M215 does not match well, but if
you have them on hand, they would still work. You will probably power limit
in the spring and fall, but the rest of the year you will probably do fine.
The M250 has a higher operating voltage for 72-cell arran
William,
Here is what I would recommend.
1. Put pairs of SQ-150s in parallel on an M250.
2. Put PC4JFs as two in series by two in parallel on M250.
3. For leftovers-two PC4JFs in series are the same as one SQ-150 so
mix and match to your heart's content.
The issue
Nick,
Thanks for the clarification-it is a mysterious threaded hole..
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nick Soleil
Sent: Wednesday, September 18, 2013 10:19 AM
To: RE-wrenches
Subject: Re: [RE-wrenches]
Dave, Gary, and Charlie,
First, the directions from the manufacturer should be the guide as to
whether a GEC is required or not. Just because a GEC terminal is located on
the equipment, does not mean that one is required. Case in point-Enphase's
new IG product does not require a GEC, yet it has
Dave,
To add to your point, the typical way to wire an ungrounded PV system is to
use modules with PV Wire-connect them to homeruns of PV Wire-then transition
at some point to standard wire in raceways. This means that the only change
from a wiring method point of view is to use PV Wire whereve
Troy,
Overcurrent device size is matched to the conductor size. The inverse time
constant nature of an overcurrent device can typically handle the surge
currents as long as conductor sizing has truly been done correctly for the
conductor. Circuit breakers are preferred to fuses because they can
Carl,
Just to be clear, the performance tests mandated by the California Energy
Commission, that all products in the U.S. follow, require that the maximum
power rating is continuous (24/7). Actually, continuous means that it can
operate for 3 hours straight at 40C (104F) (really hot). This does
William,
I have all the respect in the world for you, but I'm not referring to
"basket tray", which is only appropriate for small conductors. I'm talking
about legitimate cable tray that can be up to 12" wide and that has a top
and rungs every 12". The main facilities that use it in the United
Wrenches,
Fronius is releasing their AFCI inverters this month. They sent them to me
for CEC approval.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nathan
Stumpff
Sent: Tuesday, March 26, 2013 9:09 AM
To: re-wrenches
William,
I would strongly disagree that conduit is tried and true on rooftops. I have
rarely seen good conduit runs on rooftops. Most electricians have no clue
how to work with expansion joints. Conduit on rooftops is a bad idea in
general. Most conduit runs in big buildings are all done indoor
All,
Here is the language that has been accepted into the 2014 NEC:
690.31(C)(2)
(2) Cable Trays. PV source circuits and PV output circuits using
single-conductor cable listed and labeled as Photovoltaic (PV) wire of all
sizes with or without a Cable Tray marking/rating shall be permitt
Marco,
This should be fairly straightforward. If the whole roof is truly grounded,
you have nothing to worry about. If it is not well grounded, then you have
cause for pause.
I would recommend the new Megger MIT410 (or420 or 430) device. It has a 50V
setting which is hugely beneficial for t
William,
Nice work on the wire management side. For you and others that may not be
aware, the U.S. Dept. of Energy funded the development of an online training
version of my Field Inspection Guide for PV Systems
(http://irecusa.org/wp-content/uploads/2010/07/PV-Field-Inspection-Guide-Jun
e-2010-F-
August,
I'm not really worried about residential center fed buswork since the 120%
exception only applied residential prior to the 2008 NEC and the location of
the OCPD was not specified.
The location of the OCPD was specified in the 2008 NEC to address commercial
panelboards that are run a
boB,
The limit of 80-volts was to make an exception for single module devices
like micro-inverters and for 48-volt battery systems and smaller. A change
controller operating above 80V would be required to have an AFCI whether on
or off grid if the array is mounted on a building.
Bill.
F
August,
Who at SMA said that they won't be shipping AFCI inverters? I know they have
been manufacturing. I have two of the AFCI inverters in operation at my
office and they are very impressive. Three months of operation since startup
without a single nuisance trip and it trips every time I simu
ugust 26, 2012 11:03 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Solmetric PVA and Tigo
On 8/26/2012 7:54 AM, Jesse Dahl wrote:
> Hello,
>
> Has anyone has experience using the Solmetric PVA and optimizers? Is
there any issues?
>
> Jesse
>
You might ask Bill Brooks. He has a
Benn,
This product appears to be significantly superior to the old-school ILSCO
tin-plated copper lugs. While those lugs may have been the best thing going
10 years ago, there have been many improvements. This looks like one of
them. I would argue with the statement that tin-plated copper is in
May 16, 2012 10:48 PM
> *Subject:* [RE-wrenches] Line side taps in Hawai'i
>
> Aloha Wrenches,
>
> I have recently started working in Hawaii on the island of Oahu and
> have run into some interesting problems with the AHJ's. The biggest
> issue is nobody is allowing lin
Andy, August, and Eric,
There will likely be significant changes in the 2014 NEC to clarify the
situation you are discussing. Fault current has very little to do with this
issue.
The key distinction was used in my proposal to the 2014 NEC that removed the
statement "and conductor" in 705.1
Joel,
It ain't over until it's over. The statewide effort will not limit
transformerless inverters if I have anything to do with it. This is
something these guys got on their brain, and they won't let it go-YET. Once
they understand better that these inverters are safer, we will get them to
bac
http://solarprofessional.com/article/?file=SP4_3_pg14_QA_2
<http://solarprofessional.com/article/?file=SP4_3_pg14_QA_2&search=>
&search= (Bill Brooks article on Fuse Servicing disconnect requirements)
http://solarprofessional.com/article/?file=SP4_3_pg64_Hren
<http://solarprofessional.com/article
ches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Tuesday, December 20, 2011 7:44 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] a PV titan is to be no more
Marco,
With "BP" on the module, it means a lot more than some no name brand. Just
because
Marco,
With "BP" on the module, it means a lot more than some no name brand. Just
because they are not producing anymore does not have any impact on their
warranty obligation unless BP goes out of business-that is not likely to
happen in your lifetime.
Bill.
From: re-wrenches-boun...@li
On 12/1/2011 14:56, Gary Willett wrote:
Ray:
Look at Appendix F in the Expedited Permit Process for PV Systems - A
Standardized Process for the Review of Small-Scale PV Systems Prepared by
Bill Brooks, P.E. Brooks Engineering
This document provides the ASHRE temperatures for a
Open circuit. If something comes apart internally at short circuit you have
a possible arc.
Bill.
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of jay peltz
Sent: Wednesday, November 30, 2011 7:07 AM
To: RE-
Folks,
One factor often overlooked when calculating minimum system voltage is
degradation of the array and rating variations of the modules.
If you assume 0.5% loss in voltage per year, you need to factor a 10% higher
voltage at year one.
Manufacturers tolerance on voltage and current c
Keith,
This is easy to test. Simple take an irradiance sensor, turn it upside-down
and test the irradiance on the bottom surface of any PV array. It will vary
greatly based on exposure to reflected light and so on, but it will rarely
be above 100 W/m^2. 10% improvement is an absolute maximum fo
Keith,
As I board a flight from Maui to Oahu this evening, this curve tracer rocks.
It is truly what I have been wait for over a decade. Everyone should buy one
and I don't even get royalties for saying that.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun
Google it. It is on the www.irecusa.org website. Click on publications. You
probably missed part of the URL.
Bill.
___
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.
All,
A resource that all wrenches need to be aware of and read is a document
published by the Interstate Renewable Energy Council called, "Connecting to
the Grid". It includes a good laymen's explanation of anti-islanding--which
goes far beyond voltage and frequency limits. URL below
http://irecu
Nick,
If your voltage is low and there is no ground fault, either positive and
negative are connected mid string, bringing the voltage down, or a bunch of
modules never got connected in series. In either case, the Voc difference
between the two strings will create a significant current flow at
Nick,
How can you conclude that there was nothing wrong in regard to ground
faults. What was your reasoning that lead you to that conclusion. I think
there is doubt on your conclusion unless half the wiring in the second
string is backwards.
Bill.
From: re-wrenches-boun...@lists.re-wren
Marco,
The only argument you can make for a system like yours is to say that if the
modules degrade at different rates, then the Tigo optimizers make sense.
Otherwise, I can't see how it could be anything but a slight loss. Tough
call for $15k. Other attributes like monitoring and shutting off
Marco,
Why?-is this a low current string or a really high current feeder?
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Marco
Mangelsdorf
Sent: Monday, June 06, 2011 4:05 PM
To: 'RE-wrenches'
Subject: [RE-wrenches]
Andrew and Troy,
While I can't speak for NABCEP, I would expect that NABCEP should be very
opposed to this type of use of their logo. NABCEP does not certify the work
that a NABCEP certificant does. They only certify that the installer has met
the obligations for certification. There is a HUGE
Jim,
Having taught classes in New Jersey on the subject, I can tell you that the
fire service is looking into these types of requirements for ground-mounted
systems. The 2012 IFC only includes requirements for buffer areas around the
perimeter. Whether a fire truck needs to get around a facilit
@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Friday, March 04, 2011 5:51 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] grounding the Enphase inverter
The better question is why is there a solid ground in the inverter.
As I stated before-we are talking about system groun
The better question is why is there a solid ground in the inverter.
As I stated before-we are talking about system grounding-with 100+ years of
electrical history and precedent to back it up.
System grounding rules are not open to a lot of discussion. That is why my
recommendation since be
g] On Behalf Of Bill Brooks
Sent: Thursday, March 03, 2011 10:48 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] grounding the Enphase inverter
All,
While there is ambiguity in the 2008 NEC in 690.47(C) on the requirements
for system grounding of PV systems, the 2011 NEC in 690.47(C) clar
ional electrode, install a j-box at the
point near ground-level where the conduit transitions from vertical to
horizontal and install an irreversibly spliced bare 6AWG to run from the
j-box to a ground rod below the j-box--mildly painful, but very doable.
Bill.
Bill Brooks, PE
Principal
Brooks Engine
ercial buildings? How about an
enclosed MW in a box solution in the middle of a MW power plant, is that a
building? I like for example that in the 600V max limitation that it
specifies 1 or 2 family dwellings, leaving small & large commercial
buildings opportunity to have 1000V systems.
Any c
Karl,
What you are referring to is a "reverse power relay." These are common
devices used for customer-generators. Basler is one company that makes them.
Just google the topic and you will find several companies. The utility may
have a preferred product so go with them if they have one.
Th
Peter and Larry,
Brian's post was correct and consistent with the 2011 NEC. It is not correct
to apply both 1.25 factors on the dc side. This has been done for years, but
it is inconsistent with the rest of the code. Conditions of use are only
applied to maximum current-defined by 690.8(A) as r
To add to Brian's well formulated response, the 2011 NEC is much more
detailed and accurate on this subject. Oversizing wire is not a big deal on
residential systems, but it is prohibitively expensive in megawatt jobs.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenche
Any chance for solar resource monitoring to help the data make sense?
Irradiance monitoring is necessary to understand performance. Does SolarEdge
have that option yet?
Bill.
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.o
Power LLC
462 Solar Way Drive
Hyde Park, VT 05655
www.independentpowerllc.com
NABCEP Certified PV Installer
Vermont Solar Partner
23 Years Experience, (802) 888-7194
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill B
energy
to throw my graph off by very much.
Kent Osterberg
Blue Mountain Solar, Inc.
Bill Brooks wrote:
Kent,
How often were your data records? To capture edge of cloud effects, you need
one-second data. Not many people gather that fast or that much data on
inverters. I don't thin
Kent,
How often were your data records? To capture edge of cloud effects, you need
one-second data. Not many people gather that fast or that much data on
inverters. I don't think there is that much energy in these spikes, but they
are real and make some difference. 15-minute average data will c
ow on residential it makes no sense.
However for commercial that might have to pay extra for PF issues, to have
the inverter adjust for this makes sense.
Its the reason they( inverter companies ) are doing it.
I"ve heard a better more complete reason of course from Bill Brooks, who
maybe can chime
Jesse,
The map is in degrees C not F and it is for the mean extreme minimum drybulb
temperature from the ASHRAE Fundamentals 2009 edition.
It is a statistical lowest expected temperature for calculating the maximum
voltage of a PV array.
Bill.
-Original Message-
From: re-wrenches-boun..
Jamie,
The 6kVA imbalance limit, as you point out, is for 120V/240 split phase
services, not 3-phase. It comes from California’s Rule 21 interconnection rules
adopted by each California utility. As the technical facilitator of the
development of Rule 21, I had a lot to do with the 6kVA numbe
...@luminalt.com>
>
> *From:*re-wrenches-boun...@lists.re-wrenches.org
> <mailto:re-wrenches-boun...@lists.re-wrenches.org>
> [mailto:re-wrenches-boun...@lists.re-wrenches.org
> <mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of *Bill
> Brook
Marco,
All 3-phase services, and single split-phase services has imbalances from
time to time. The question of whether the imbalance is problematic depends
on the size of the imbalance relative to the service transformer. Since
3-phase services are generally larger, a 10kW phase-to-phase connec
Peter,
Are you making your measurement before and after the inverter breaker? I
believe what you are attributing to the breaker is actually the voltage rise
from the service transformer, through the service conductors, through the
service panel. A 3-Volt drop is common when adding a 4kW load to a
Sam,
Panel Claw requires conduit to properly protect conductors, particularly
row-to-row. I have seen bundling done, but it will not last long. Panel Claw
is just one of many companies that do not provide much, if any, wire
management strategies.
Bill.
From: re-wrenches-boun...@lists.re
: www.alterisinc.com
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Wednesday, November 17, 2010 9:11 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Megger for array testing
Meggerers,
Although sho
Meggerers,
Although shorting the terminals to perform the megger tests may provide the
most uniform voltage profile, it is difficult to perform on many arrays and
adds unnecessary complexity to a test that needs to become routine for all
PV installations.
The appropriate way to perform the
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