David,
They are supposed to be mounted outside boxes so that you can clearly see
when they have been used up. Sand makes glass that expands and breaks the
plastic. They used to be porcelain for the very same reason. If you are
concerned about unqualified people coming in contact with conductors
Peter,
Be a little more careful in your choice of subjects. You are talking about
the SunPower IFF clip. I have not heard this story, but I don't doubt it.
There have been significant changes at UL and ETL, the two largest listers
of PV modules, in the area of evaluating grounding equipment for PV
ax 323-258-8885
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Sunday, September 12, 2010 8:50 PM
To: 'RE-wrenches'
Cc: 'Christopher Flueckiger'; Tim Zgonena
Subject: Re: [RE-
Andrew,
You make a decent argument, but it is flawed. A tech working on a faulted
array removing modules without disabling them is likely to be injured
whether or not there is a lug or a clip. The circuit must be disabled before
taking loose anything. Not an easy task, but necessary. The argume
Please STOP using this subject heading. It is disrespectful to one
manufacturer and is annoying. Call it Array Grounding or anything but this.
Bill.
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Options &
Mark and Rebekah,
The term "continuous" is a requirement for any circuit and implies
electrical continuity and current-carrying capability. Both the GEC and EGC
must be continuous or you don't got one. It is not defined in NEC Article
100.
What most people are referring to when they say tha
Joel,
The problem is not with the rating of the modules. It is with the way we
install them. The air gap is a problem. If HVAC systems were installed like
PV modules, they would have the same problem. There will be changes of some
sort coming in the next year or so. The IBC in 2012 will require "P
Marco,
The company was purposely not identified. I believe the young man fell
through a skylight while moving equipment during construction. Much more
likely way to die since most people assume a skylight will bear their weight
if they fall against it. Edge of roof falls definitely occur, but s
Benn and Bill,
Paul and I got together last week and took a beta unit out to test several
arrays at PVUSA. I’m very impressed with the capabilities. It has been a long
time coming, but this product will revolutionize how most companies test,
analyze, and commission PV systems. Hats off to So
All,
Transformerless inverters are simply a subset of ungrounded or resistively
grounded PV systems covered by the NEC in 690.35 since the 2005 code cycle.
Power-One has been marketing their ungrounded inverter in the U.S. for several
years now. It was listed by CSA. The requirements for ung
It has to do with the development of a “double-insulated” conductor needed for
ungrounded systems. PV Wire is double-insulated while USE-2 is not tested as
double insulated. It is analogous to double-insulated tools in the U.S. that do
not require a ground wire.
Bill.
From: re-wrenches-b
Hans,
It is not correct that you will have twice the disconnects necessarily. Most
switches require passing through the disconnect twice. This must be done on
the one ungrounded conductor for grounded systems, or the two ungrounded
conductors with ungrounded systems. It is a circuit and it simply
, it is a large
improvement over where we are today. Don’t be surprised if things change about
how we do GFPs soon. If I have anything to do with it, it is going to happen.
The current hazardous situation, and bad information about the Bakersfield
fire, cannot continue.
Bill.
Bill Brooks
here we are today. Don't be
surprised if things change about how we do GFPs soon. If I have anything to
do with it, it is going to happen. The current hazardous situation, and bad
information about the Bakersfield fire, cannot continue.
Bill.
Bill Brooks, PE
Principal
Brooks Engineerin
00 PM, Bill Brooks wrote:
Ray,
The reason I mentioned resistively grounded systems is that anything
requires a ground, like SunPower, could use a resistive ground instead of
being ungrounded. This solves SunPower polarization issue and is the way
many of their systems are installed in E
Benn,
If it were me, I would mount rails on the S-5! Clamps so that you can mount
the micro-inverters on the rails. It is not good to mount the inverters on
the module frames. Although some modules may be able to physically handle
it, as you noted, you will probably void the warranty. The weigh
Drake,
I recommend using 4'x8' panels of lattice work that is either wood or PVC so
that you don't have worry about grounding the material. It is reasonably
attractive and can hide some of the ugly parts of the array. The panels can
be held on with battens that screw into the structural member and
Mark,
The fact is you can't legally walk up and touch NM cable anymore. Whenever
your house was built, that may have been code compliant, but not since the
early 1990s has that been allowed. You may think a wooden lattice work is
insufficient protection, but the code disagrees with you as a minimu
of the system we build.
Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
www.berkeleysolar.com
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: T
n...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Friday, October 22, 2010 8:27 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Ground Mount Screening
Mark,
I certainly was not implying that you were in any way unintelligent. I was
merely suggesting that fences or only one means of
Rebecca,
Although I recommended delaying the implementation of arc-fault detectors,
the Code Making Panel felt that the hazard justified the requirement.
Article 90.4 clarifies the NEC's approach to your concern:
90.4 (paragraph 3)
This Code may require new products, construct
Jay,
It is my understand that the distance is quite far. If neighbors have
systems, they have to assign the inverters so they are not counted by the
neighboring web interfaces. How far do you need it to run?
Bill.
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto
William,
Apparently this fire was started by miswiring a combiner box. Most likely
reverse polarity of a string or whole combiner box feeder at the inverter.
Details to come.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On B
Eric,
Your concern over shorting the current carrying conductors to a single
conductor would require multiple faults-not that this is impossible-but we
generally are not required to design for it. Squirrels would probably be the
most likely way to cause such an event.
Since all four strings
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
: 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
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
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
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
...@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
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
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..
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
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
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
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
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
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
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
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
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
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
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
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
@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
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
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
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]
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
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
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
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
Google it. It is on the www.irecusa.org website. Click on publications. You
probably missed part of the URL.
Bill.
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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
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
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
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-
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
es.org] On Behalf Of David
Palumbo
Sent: Tuesday, April 28, 2009 7:59 AM
To: gilliga...@gmail.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] To Megger or not to Megger
Matt,
"Muggering", I think that will catch on. The last post, I think, ol' Uncle
Bill Brooks (4/13/09
recent class here in Vermont was great. Thanks.
---Bill Brooks wrote:
Just to add punctuation to this thread, I always recommend that contractors
megger their arrays, because it has saved my butt several times.
--- end of quote ---
--- Matt Lafferty wrote:
I only meggered the actual arrays on
Since we are talking lay-in lugs, the WEEB-Lug is clearly superior to either
the Burndy or Ilsco lugs because it takes 1/4" hardware, has a hex head set
screw set in a much more convenient manner and has a bonding plate so that
an anodized aluminum surface does not have to be ground off. Not sure I
All,
How many of these Chinese manufacturers will still be in existence in 5
years (probably less than half)? Are you really willing to risk a company
and reputation for a few pennies per watt? Certainly several of the big
companies are likely to survive, but you are playing a new game of "Chinese
Peter and all,
The Enphase product is the only one of its kind on the market currently
(there will be more). Their sales are far beyond where they thought they
were going to be-good and bad news. Great for them to be confirmed in their
market prediction. Bad for the people who are anxious to ge
Not sure what "CEC specced panels" means. Everything CEC must be listed to
UL1703-BP has had fires with UL/CEC modules, and so have other companies.
The question raised here is what defect caused the recall?
This is not unexpected, but it is horrible. Just think if a major company
like REC can
Allan,
Check out my website at www.brooksolar.com/services. The recent Expedited
Permit Process that I helped produce for the US Dept. of Energy is on that
page in pdf that you can download. It explains the rationale behind why
anything under 5 PSF is fine if the roof structure is standard (eng
Mark and Jeff,
To be clear, manufacturers do not supply the data. It is required to be
tested by a Nationally Recognized Testing Laboratory (NRTL). Mark's message
could be misconstrued as the data being something Fronius cooked up.
On another note. Anyone notice Fronius inverters having tro
3-258-8883, Mobile 323-839-6108, Fax 323-258-8885
_
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Wednesday, July 08, 2009 4:20 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Efficiency Curves
eries string. Broken modules produce
high currents that become pyrovoltaic without diodes.
Bill.
Bill Brooks, PE
Brooks Engineering
873 Kells Circle
Vacaville, CA 95688
Office and Mobile: 707-332-0761
Office Fax: 707-451-7739
email: b...@brooksolar.com
www.BrookSolar.com
Chula Vista has been difficult on a number of fronts for the past few years.
I'm not sure what is behind it. This is a reference from an old Los Angeles
Fire Department regulation. It was invented by a person at LA who still
thinks it's a good idea. I don't doubt that it could not be developed. My
Jay,
I bought two insulation testers (Megger is a brand name) in April. A used
Fluke 1520 off Ebay for $275 and a new inexpensive (cheap) insulation tester
on Amazon (Electronic Specialties 550 Insulation Tester for $162). Both work
fine. The Fluke has better accuracy that I need for very speciali
Bruce,
Use a standard 125-amp panel with a 100-amp main breaker. This is a very
common panel and does not require downsizing the main breaker any further
(it is already downsized). It allows up to a 50-amp PV breaker.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wren
age drop--it is at least twice as important because it may
determine whether or not the system runs.
Bill.
Bill Brooks, PE
Brooks Engineering
873 Kells Circle
Vacaville, CA 95688
Office and Mobile: 707-332-0761
Office Fax: 707-451-7739
email: b...@brooksolar.com
www.BrookSolar.com
-
All,
If you are looking for voltage regulators that can be placed on a home or
business, check out www.microplanet.com. They are selling these around the
world for energy efficiency purposes. Bring high voltage down makes
equipment run more efficiently and keeps the PV system from tripping. I'm
no
Peter,
The excursion time depends on how high the excursion is. There is a longer
grace period for being just above or below the limits to allow for inverters
to ride through normal transients. However, beyond that are some very short
timeframes for excessive transients and large excursions. There
Kirk,
I'm fairly confident that if the manufacturer does not specify an angle for
NEMA 3R (rainproof) that the default is vertical. In special cases (e.g.
Outback PSPV), the NEMA 3R tests are requested at an angle, but this is
fairly rare. Upshot is that NEMA 3R boxes normally cannot be mounted
Jerry,
The Canadian requirements are simplistic and based on the 1996 and prior NEC.
Canada is simply not keeping their code up to date and recognizing the fact
that their western coast has significantly milder weather and that thin films
do not have the same temperature coefficients as crys
Roger,
Why would a legitimate contractor argue against this reduced incentive (it
is not a penalty at all)? This is simply acknowledging the fact that
operating a business and providing a long-term system warranty costs money
that a self-installer does not have to carry. This actually came fro
lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Monday, August 31, 2009 10:57 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Installer's grant
Roger,
Why would a legitimate contractor argue against this reduced incentive (it
Drake,
My points related to non-contractor installs which came up after you raised
your initial concern. I think Ohio is being ridiculous for not providing
incentives to their qualified installers installing on their own facilities.
This makes absolutely no sense. You can tell them that for me.
Peter and Nick,
I believe the original question related to two different orientations in the
same series string. Peter, your response was related to two parallel strings
of the same length run into the same inverter. These are two EXTREMELY
different scenarios. They have been discussed in detai
Marco and Mick,
I don't think the issue is whether SolarWorld wants the liability. They have
the liability. They bought the company. This is not like GE Energy where
they were very careful to just buy AstroPower's equipment in a fire sale. I
still think GE is liable, but I'm sure their lawyers
Which ones? They produced several different boxes and combiner boards.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Marco
Mangelsdorf
Sent: Wednesday, September 30, 2009 7:02 PM
To: 'RE-wrenches'
Subject: [RE-wrenches]
Folks,
The new SAM (Solar Advisor Model) product from NREL is your answer. I’m just
learning about it, but it looks like it can do everything you need related to
analysis, and it is free. It uses TMY2 data sets that are hourly. You can
argue with the validity of the TMY2 data sets for your
August and Max,
If all you are doing in supporting the conductors, PVC conduit is sufficient
with protective bushings on each end. Once you go to EMT, then grounding
bushings must be installed at both ends and the EGC needs to pick up those
bushings. More expensive and time consuming, but it
August,
Home Depot now sells bonding bushings for EMT down to ½, which should solve
the availability issue. I was very surprised to see them last trip to the HD
money pit.
Bill.
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Mark,
Although this exception is allowed, I think it is bad practice in the field.
We will probably see the NEC revoke this exception within the next few
cycles, and it may be revoked for PV systems much sooner. Relying on box
connections to carry the low fault currents inherent in PV systems i
what the sun does to PVC conduit)
Max Balchowsky
SEE Systems
760-403-6810
_
From: Bill Brooks
To: RE-wrenches
Sent: Friday, October 9, 2009 10:20:19 AM
Subject: Re: [RE-wrenches] Rooftop wiring methods between multiple subarrays
August and Max,
If all you are doi
ground lug on the last row to take the ground into the junction box and
down......
Max
_
From: Bill Brooks
To: RE-wrenches
Sent: Tuesday, October 13, 2009 7:59:13 AM
Subject: Re: [RE-wrenches] Rooftop wiring methods between multiple subarrays
Max,
I’m not sure I under
Joel,
Any idea who is developing this? It sounds like whoever is doing this is not
necessarily in the loop with many other standards activities that are going
on. We should encourage anyone doing work in solar codes and standards to be
involved with the U.S. Department of Energy's Solar America Bo
Marco and Joel,
In the latest version of the Expedited Permit Process, I was required to
remove references to real manufacturers in my example problem. I made up a
company called "American Solar" in true Canadian Solar style. It is really a
shortened version of the company "American Solar Syste
Lee,
Your idea about 2 strings of 16 is fine on a Fronius IG2000. The voltage is
correct and the inverter power is more than sufficient. There is no
difference at all in the way module bypass diodes were done then (early
1990s) as now. You want to check the Voc of each module to make sure there
Mark,
The readily accessible disconnect at the inverter is all that is necessary
according to the code. There may be practical reasons for additional
disconnects, but if the system has no combiner box, or the combiner is at
the inverter, only the disconnect at the inverter is required.
Bill
William,
I'm not sure what the struggle is about here. If you have a combiner box,
you should always have a disconnect nearby to service the fuses. The 2011
NEC will require such a disconnect. It is a no-brainer on a ground mounted
system. A roof-mounted residential system of 4 strings or less
David and Kirpal,
It is ultimately up to the AHJ whether or not they accept the
Schneider/Square D self certification. That is a judgment call the installer
needs to clear with the AHJ. That being said, having Square D behind the
rating of a switch is a whole lot more than any one of the smalle
bout dc disconnects needing to be listed to some
special PV standard.
Is there a movement in this direction? Is there a UL1741 standard for dc
discos that is somehow different that the standard used for other dc
disconnects?
Best,
David
On 1/11/10 5:28 PM, "Bill Brooks" wrote:
Andrew,
It does not exist. We tried like crazy to get it into the 2011 NEC, but to
no avail. At the last second the proposal was put on hold until the 2014
NEC. Major bummer. For now it can only be done with AHJ approval. Many allow
it but it is not in the NEC. Alternatively you must use the su
r
Vermont Solar Engineering
802.863.1202
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From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Wednesday,
August,
Probably the best simple explanation is in "Connecting to the Grid",
published by the Interstate Renewable Energy Council and the North Carolina
Solar Center. It is in its 6th edition. I wrote the original version of the
document over 15 years ago.
Bill.
Quote from Document:
"Grid-tied
The serving transformer is also an issue. I've seen 800-amp service
conductors on a 25kVA transformer. Just because you have wires large enough
for a 400-amp service, does not mean you have a transformer capable of
delivering 400-amps continuous. That is why you have to work with the
serving utilit
Dave,
All line side connections must have overcurrent protection (230.91) at the
disconnecting means. Article 230.70 through 230.95 is what generally governs
these connections. Without rewriting John Wiles' articles on this subject,
here are a few quick pointers.
The basic rule to remember,
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