Hi Jason,I don't know if this has been suggested yet, when we have electrical equipment in exterior and damp locations we're a firm believer in putting no-ox or electrical grease on all electrical connections, coating fuse ends and contact points, disco conductor terminal points, CB wire lands, CBs on the buss, ground conductor to ground buss, etc. This has been saving me from a lot of grief when it comes to resistance and corrosion forming in connections, splices, contact locations. Probably leftover from early on learning that coating and assembling battery lugs and cable ends with high temperature lithium grease works well to keep the oxygen off and stop oxidation. Chris Worcester chris at solarwindworks.com530-448-9692Sent from my Samsung Galaxy s9.
-------- Original message --------From: Jason Szumlanski <jason at floridasolardesigngroup.com> Date: 11/19/20 7:15 AM (GMT-08:00) To: RE-wrenches <re-wrenches at lists.re-wrenches.org> Subject: Re: [RE-wrenches] Enphase intermittent breaker trippjng All good info.I plan to take my FLIR One out next time. I can paint it white in both cases I suppose. As for the temps, the high ambient here is 93ºF per ASHRAE. Inside attics, we can see temps exceeding 140ºF here. We don't derate conductors for that. I'm not sure where 114ºF comes from, but I get the point. The interior of the enclosure can certainly get blazing hot. This definitely seems to be a heat-related issue whether the NEC intent has been met or not. Upping the tap conductors to #4 or larger would not be difficult or expensive to accomplish. I will likely make that our new standard for 50A and 60A calculated circuits for supply-side interconnections made outdoors.JasonOn Wed, Nov 18, 2020 at 8:13 PM Ray <ray at solarray.com> wrote:
What is the brand and model of the disconnect? Temp ratings of
the terminals? I've definitely had fuse holders not make good
contact with the fuses and burn the fuses at one end, instead of
in the middle. Have you looked at it with a Thermal imaging
camera when its operating to see if its hot on one end of the
fuse?
Second, depending on the temperature it would be hitting inside
the enclosure in the sun, you could be exceeding the rating of the
#6 conductor. Assuming terminals rated at 75C, then from 310.16,
a #6 is rated 65 A, but derate for temperature of 114F inside the
enclosure gets you to .82 x 65 = 53.3, which is a bit less than
the 54.45 that Dave just calculated for continuous duty.
What color is the disconnect painted? any chance of painting it
white?
Ray Walters
Remote Solar
303 505-8760
On 11/18/20 4:16 PM, Dave Tedeyan
wrote:
Jason,
Bright sunny days, disconnect on the west side of house,
maybe in the sun? 43.56A * 1.25 for continuous duty = 54.45A.
If these disconnects are also baking in the sun, maybe the
extra ambient heat is enough to push it over the edge? Just a
thought.
Cheers,
Dave
Dave Tedeyan,
PE
Senior Engineer
| Taitem Engineering, PC
110 South Albany
Street |
Ithaca, NY 14850
o. 607.277.1118
x121 f. 607.277.2119
www.taitem.com
Solar • Sustainability • Energy • Design
Certified
B-Corporation since 2013
On Wed, Nov 18, 2020 at 3:41
PM Jay <jay.peltz at gmail.com> wrote:
Hi Jason
Any chance for some photos?
Jay
On Nov 18, 2020, at 12:18 PM,
Jason Szumlanski <jason at floridasolardesigngroup.com>
wrote:
The
plot thickens on the fuse blowing issue. Again, we
tore the Enphase IQ system apart looking for any
reason for the fuse to keep blowing. We
reconfirmed torque on all line side conductors to
the service (supply side interconnection using
Polaris taps).
Low
and behold, I get a second client with the exact
same issue yesterday. The circumstances are
eerily alike. Both disconnects are located on the
west side of the house and have 36 IQ7+
microinverters on an IQ Combiner, requiring 60A
fuses on the 60A fusible disconnect. The combined
inverter output rating is 43.56A. The
interconnections are identical with #6 THHN 90ºC
conductors and Polaris taps. Both disconnects have
conductors on the right-hand side line-side
terminal that are discolored (the copper is
silvery, the insulation is not burned). The fuses
blow at peak current around 1:30 pm, only on
bright and sunny days.
I'm
starting to suspect a faulty fusible disconnect
switch. Maybe the blades are not making proper
contact with the line side terminals.
For
the client who is having regular/frequent fuses
blowing I plan to replace the disconnect with a
heavy-duty version or possibly get a 100A
disconnect with fuse reducers. I'm not sure which
option would yield a better test. I might also
switch brands.
Currently,
we are using GE TG3222R. The fuses are Bussman
FRN-R Time Delay. I have to believe a heavy-duty
switch would be less susceptible to this, but
maybe a higher rated one would be a better option.
I'm not a fan of fuse reducers, however.
Jason
Szumlanski
Florida
Solar Design Group
On Sun, Aug 30,
2020 at 5:54 PM Jason Szumlanski <jason at floridasolardesigngroup.com>
wrote:
The
tripping breaker occurred at random times,
even at night. No weather-related
correlation.
I
have more research to do to see when this
fuse issue is happening, but previous visits
showed no water ingress. I'm not sure about
temperature.
On Thu, Aug
27, 2020 at 8:51 PM Jay <jay.peltz at gmail.com>
wrote:
Hi Jason
One thought I have about
the blowing fuse is to check it with a
IR tool.
I suspect a poor connection
of the fuse to holder which during
higher air temp is causing it to fail.
I’m assuming that the
correct amp size and slow blow fuse Is
installed and that the wire connections
are done correctly. But again an IR tool
during peak heat would be a good test.
About the enphase fix, wow
what a head scratcher. But given that
it’s fixed it means that it’s not a
short, but enough amps going through
over enough time to trip it. I wonder if
a magnetic hydraulic vs thermal breaker
( CBI vs CH etc) would have worked?
Is that breaker box ever in
the sun? Is there any Correlation
between high ambient temperatures and
tripping?
It sure would keep me up at
night too
Jay
On Aug 27, 2020,
at 4:29 PM, Jason Szumlanski <jason at floridasolardesigngroup.com>
wrote:
So the resolution to this is
in... But I still have no idea
what was wrong.
The string of 10
offending microinverters was split
into 5 and 5. We had a spare
breaker in the IQ Combiner so it
was relatively easy to run another
branch circuit. It has been over
two months with no recurrence. So
the issue seems to be resolved,
but again, no idea why.
So here we go
again... On another system we have
a similar problem now. In this
case it is supply side
interconnected with a fusible
disconnect. The same fuse (same
line) keeps blowing every few to
several weeks. We can't find any
home run wiring issues or issues
with terminator caps. There are no
apparent faults in the AC
Combiner. We have no idea why
this is happening. But in this
system, just the fuse blows, not
one of the individual branch
circuit breakers.
This is getting very
frustrating. And this is way more
serious because fuses and service
calls are expensive and I can't
isolate the issue to one branch
circuit. I don't even know where
to start. Leaving each circuit
disconnected for several weeks to
prove a negative is an untenable
suggestion to make to a client.
But I don't see any other good
options.
Jason Szumlanski
On Tue, Jun
9, 2020, 3:42 PM Jason
Szumlanski <jason at floridasolardesigngroup.com>
wrote:
Yes,
we double-checked that.
I have seen that happen
before and it's one of
my early diagnostic
steps for something like
this.
On
Tue, Jun 9, 2020 at 9:18
AM Mac Lewis <maclewis1 at gmail.com>
wrote:
Hi Jason,
Are you certain
that the branch
circuits aren't
crisscrossed
somewhere, meaning
that an L1 branch 1,
isn't connected to
an L2 branch 2?
That could explain
two different
breakers tripping.
Good luck
On
Wed, Jun 3, 2020 at
1:07 PM Jason
Szumlanski <jason at floridasolardesigngroup.com>
wrote:
Undoubtedly,
the
termination
caps are the
second thing
we check after
the rooftop
junction box(es).
These are
prone to
installation
errors, even
when the right
parts are
used. And
given the
cost, I've
thought very
long and hard
about
abandoning
them
altogether and
terminating
strings in
small j-boxes
with
watertight
fittings. But
in this case,
there was no
evidence of
improper
installation
(we replaced
them) and it
was not
correlated to
rain events.
We
are well
equipped with
bare Q-cable
and field
wireables that
we could use
for
troubleshooting
to bypass
certain
sections, but
the
intermittent
nature of the
problem and
unpredictable
timeframe
between faults
is very
frustrating.
While this is
a
rare occurrence,
it is
definitely a
"con" to
consider when
comparing
string vs.
microinverters
that I had not
strongly
considered in
the past. I'm
intent on
getting to the
bottom of this
in order to
learn what to
look for in
the future and
how to
approach
diagnoses of
Enphase
branch circuit faults.
Jason
On
Wed, Jun 3,
2020 at 2:31
PM Amos Post
<integrityenergy101 at gmail.com>
wrote:
I was
just at a site
last week
where the
Enphase branch
circuit
breaker,
outside
utility
disconnect
breaker, and
feed breaker
in the main
panel all
tripped
simultaneously,
and it
happened about
1 hour before
I showed up
onsite. The
customer said
it had
happened 1
other time
last fall but
that time it
was just the 1
branch circuit
in the Enphase
combiner
panel.
Interestingly
the customer
mentioned that
he had just
washed off the
panels, also
about 1 hour
before I got
there. I went
on the roof
and found that
the installing
contractor had
not put on the
Enphase
termination
caps. 1
string was
wire-nutted
with regular
wire nuts and
sitting on the
roof, and the
roof was damp
right there.
This was a
fairly flat
roof. The
other micro
trunk cable
was just cut
with no
protection at
all, tied to
the rail…
<IE
LOGO
150x78.jpg>
Amos Post
Integrity
Energy
W 802.763.7023
C
802.291.2188
ienergyVT.com
Facebook
On Jun 3,
2020, at 2:05
PM, Jason
Szumlanski
<jason at floridasolardesigngroup.com>
wrote:
The
breaker in the
main panel IS
tripping
simultaneously
with one of
the branch
circuit
breakers each
time.
On Wed, Jun 3, 2020 at 12:43 PM Jay <jay.peltz at gmail.com>
wrote:
A
question that
keeps nagging
me is why do
these breakers
trip and not
the breaker in
the main
panel?
Presuming
there is a 40
amp in the
main
I
would have
thought that
given all the
times the
breakers have
tripped at
some point
that one would
have tripped
and I can’t
understand why
not?
Jay
On
Jun 3, 2020,
at 8:27 AM,
Jerry Shafer
<jerrysgarage01 at gmail.com>
wrote:
Wrenches
Looking
g at the
bigger breaker
tripping at
the same time
is very likely
do to response
time of the
breaker
nothing more.
As l suggested
in a previous
message. Use a
non bridged
breaker to see
if it is one
or both legs
that trip.
Also an eguage
will help to
see what if
anything leads
up to the
failure and
when.
Jerry
Jerry
On Wed, Jun 3, 2020, 7:58 AM Jason Szumlanski <jason at floridasolardesigngroup.com> wrote:
I
wonder about
that. Of
course, it
could be the
"inverter
output
circuit"
having a fault
in the wiring
still (an
intermittent
issue
somewhere
within the IQ
cable or home
run wiring).
But internal
to the
microinverter,
is it possible
that a fault
could still
occur at
night? I had a
suggestion
from another
wrench that
there are film
capacitors on
the AC output
side, but are
these isolated
when there is
no DC input?
It seems
unlikely that
this would be
an issue, but
I have seen
microinverters
reporting a
couple of
watts at night
(in
Enlighten).
I'm not sure
how real that
is.
The
overriding
question I
have is what
kind of fault
would cause
BOTH a branch
circuit and
the main solar
breaker to
trip
simultaneously?
That seems odd
to me. If any
normal load
branch circuit
has a fault,
you don't
often see
premises main
breakers
tripping, or
even feeder
circuit
breakers.
I
got to
thinking that
maybe there is
some kind of
issue between
the BR220 and
CH240 breakers
not playing
nicely
together. But
I would think
this would be
a well-known
issue because
I'm sure there
are tons of CH
feeder
breakers in
the wild with
BR branch
circuits
downstream.
On Tue, Jun 2, 2020 at 9:25 AM <drake.chamberlin at redwoodalliance.org>
wrote:
If it trips
at night, we
know it is not
the output
from the
inverters
causing the
tripping. The
current must
be coming from
the grid.
---
On
2020-06-01
12:05, Jason
Szumlanski
wrote:
It's
not weather.
It's at all
times of the
day and night,
and I
confirmed that
there is no
correlation to
rain or high
winds. That
was my first
suspicion.
On
Mon, Jun 1,
2020 at 10:27
AM Ray <ray at solarray.com> wrote:
Is it at
all weather
related?
Rain, or high
humidity?
High
temperatures?
Do you have
any indication
what time of
day it trips
off at?
Ray Walters
Remote Solar
303 505-8760
On 6/1/20
10:23 AM,
Jason
Szumlanski
wrote:
Well,
that didn't
resolve it.
The main
breaker and a
branch circuit
breaker
tripped again
a few days
ago. It was
the same
branch this
time.
As
my next
diagnostic
step I swapped
two circuits
(on which
breaker they
are landed).
If history is
a guide, it
will work for
about two
weeks and then
trip again.
I'm
dumbfounded. I
really don't
want to have
to tear this
whole system
apart. At this
point, if I
have to remove
all the
modules, I
feel that I
need to
replace all of
the trunk
cable which is
an expensive
proposition. I
really don't
know what else
to do at this
point.
Jason
On
Mon, May 25,
2020, 10:43 AM
Jason
Szumlanski
<jason at floridasolardesigngroup.com>
wrote:
I
strongly
suspect the
CH240 combined
breaker was
compromised
(we will see).
Since it
happened that
two different
strings
tripped, I
doubt I have
two
microinverters
with internal
faults. It has
to be the
combined
breaker. I was
just surprised
that branch
circuit
breakers were
tripping
simultaneously with
the combined
output
breaker.
Of
all the supply
side connected
systems I have
installed, I
have never
seen a
combined
output fusible
disconnect
fuse blow, but
I have seen
many combined
output
breakers
tripped. I was
worried early
on that I
would be
replacing
fuses
constantly,
but that has
not been an
issue
whatsoever.
On
Thu, May 21,
2020 at 11:15
AM <scot.arey at solarcentex.com>
wrote:
Actually,
we had a IQ7
string loaded
up to its max
panel size and
max string
length and in
the spring on
cool, clear
day, it
tripped the
string's
associated
breaker in the
Enphase
combiner.
We reset
but of course
that breaker
was impaired
and it tripped
again. We
replaced and
never had an
issue going
forward. We
suspect the
breaker was
less than
perfect from
the start as
we've add
equally nice
days since.
This almost
reminds me of
loading up
Outback FM80.
It says 4,000
watts but in
reality, 3,600
is the max
when amps
spike. I will
be extra
careful going
forward on IQ7
string length
when going to
the max
published...
My story.
Scot
From: RE-wrenches
<re-wrenches-bounces at lists.re-wrenches.org> On
Behalf Of Jason
Szumlanski
Sent: Thursday,
May 21, 2020
8:57 AM
To: RE-wrenches
<re-wrenches at lists.re-wrenches.org>
Subject: [RE-wrenches]
Enphase
intermittent
breaker
trippjng
I'm trying
to resolve an
intermittent
frustrating
problem with
and Enphase IQ
system. There
are three AC
Branch
circuits of 9
microinverters
each coming
into an
Enphase AC
combiner.
What has
been happening
is one of the
BR220 branch
circuit
breakers and
the combine
CH240 breaker
in the main
backfed load
center have
been tripping
simultaneously. It has happened about four times in the last 6 months.
It was always
the same
branch circuit
breaker, so we
kept
investigating
that string,
checking the
junction box,
trunk cable,
and cap, etc.
Finally we
swapped out
the BR220
breaker.
Fast
forward 4
weeks, and we
got another
call. This
time a
different
branch circuit
breaker and
the main
breaker
tripped
simultaneously.
We checked
that branch
circuit and
could not find
any fault. It
seems unlikely
that two
branch circuit
breakers would
be faulty, so
we have now
switched out
the CH240 main
breaker in
hopes that it
is the
culprit.
I'm not
totally
confident in
this
resolution and
I have my
fingers
crossed. If
that doesn't
work, does
anyone have
any
suggestions on
another
diagnostic
step? These
intermittent
problems are a
major hassle.
One thought I
had was to
switch to a
supply side
interconnection
with a fusible
disconnect.
Maybe the
intermittent
fault would
blow one of
the two line
fuses so at
least I could
narrow it down
to which line
the fault is
on if there is
in fact a
fault.
I have
experienced
two other
tripping
breaker issues
with Enphase
systems in the
past. Neither
of them were
systems I
installed. One
turned out to
be branch
circuits that
were not
properly
paired up and
landed on
different
breakers.
Another time
we had an
inverter with
an internal
fault which
eventually"blew
up" with a
loud popping
noise and
smoke
billowing out
of it. That
happened after
resetting a
trip breaker
multiple
times. This
case seems to
be unrelated
to those
issues. I'm
perplexed.
Jason
Szumlanski
Florida
Solar Design
Group
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