WHERE do you guys get your DC switches and Combiner Boxes?

Xizang

I've been searching around for reasonable prices for DC switches, etc. that are built in simple, weatherproof units.  Anyone find a good and economical source?

vtmaps

Midnite Soler makes weatherproof combiner boxes.  Their DC circuit breakers fit in the box and make excellent DC switches.

--vtMaps

Raj174

The host of this site has very good pricing. I bought most of my equipment here. Just click on store at the top left side of the page.

Rick

Dave Angelini

The store here is great. For salt spray use West Marine. They should be selling jewelry also there...

Vic

Hi Xizang,

YES,  MidNite has a huge selection of Combiners that are in NEMA 3R  (outdoor) enclosures:

http://www.solar-electric.com/installation-parts-and-equipment/midnite/pvarco.html

Outback Power also has made very good Combiners,  and the Wind-Sun Link above shows one of those.

Almost all of these Combiners use a DIN-Rail DC circuit breaker:

http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/mnepv.html

The Link, just above,  are the most commonly used DC breakers.

Realize that you might not be in North America,  but Wind-Sun does ship internationally,  if needed.

Vic

Xizang

Good, thanks guys!

Another associated question:  On small systems, do any of you install an inline fuse on each panel?   I'm thinking about one of those rubberized weatherproof inline fuses on or near the backside of each panel, for safety sake.  Anyone think that's worth the time and investment?

vtmaps

Xizang said:

Another associated question:  On small systems, do any of you install an inline fuse on each panel?   I'm thinking about one of those rubberized weatherproof inline fuses on or near the backside of each panel, for safety sake.  Anyone think that's worth the time and investment?

Use a combiner box with circuit breakers.  How many panels are you connecting in parallel?  If there are more than two stings, you must have a fuse or circuit breaker on each string of panels.

btw, a combiner box is a great place to put a lightning arrester.

--vtMaps

Xizang

A followup:  As you know, combiner boxes are awfully expensive.  I found Square D QO weatherproof, NONmetallic load distribution boxes, which take the Square D QO breakers, at Home Depot for less than $28.  Seems like a major brand, good quality, rust-free install for a solar combiner box...

http://www.homedepot.com/p/Square-D-by-Schneider-Electric-QO-60-Amp-2-Space-4-Circuit-Outdoor-Main-Lug-Load-Center-with-Non-Metallic-Enclosure-and-Neutral-QO24L60NRNM/100174454

What do you think?

Vic

Hi Xizang,

Nice find   ...    So that will be good for two QO or one  QOB breakers with Ratings from 15,  to probably at least 30 Amps each.

The Tandem breakers  --  QOT  --  have NO DC rating,  as you probably know,  so  you could not really get four circuits.

AND,  yes,  SQ D is a Major brand  --  Schneider Electric bought SQ D some years ago.
I still spec and use SQ D panels,  boxes and breakers on projects,  and it is nice that CERTAIN QO ( ONLY QO,  QOB and QOU )  breakers will handle DC,  ONLY up to 48 VDC,  nominal  with Handle Ratings from 15 - 70 A,  ONLY.

Vic

Xizang

Vic said:

Hi Xizang,

Nice find   ...    So that will be good for two QO or one  QOB breakers with Ratings from 15,  to probably at least 30 Amps each.

The Tandem breakers  --  QOT  --  have NO DC rating,  as you probably know,  so  you could not really get four circuits.

AND,  yes,  SQ D is a Major brand  --  Schneider Electric bought SQ D some years ago.
I still spec and use SQ D panels,  boxes and breakers on projects,  and it is nice that CERTAIN QO ( ONLY QO,  QOB and QOU )  breakers will handle DC,  ONLY up to 48 VDC,  nominal  with Handle Ratings from 15 - 70 A,  ONLY.

Vic

I despise investing in and building things with materials that will quickly rust, corrode, rot or fall apart.  I love stainless, titanium, UV-stable plastics, etc.   Outdoors, the environment is trying to degrade everything back to its original state as quickly as possible.  And around the water, there's sunlight and salt and water ganging up on us.   So I was looking for a durable plastic enclosure that will resist rust and corrosion.

Do you know of a next-size larger plastic Square-D or other major brand non-metallic enclosure that might offer 4 to 6 spaces for a combiner box?   At a cheap price (for us cheapskates)?

Vic

Hi again Xizang,

I had not seen the 2/4 circuit load center before your Linking to it.

Have not seen any other Outdoor non-metallic load centers.

Searched Platt Electric's site,  and have not found anything.

Did a Google search for SQ D load centers,  and the one in your Link came up ...   will look further.

The mainstream 3R boxes from the quality manufacturers all have very good paint on them,  and,  generally will endure outdoor,  direct exposure for three or more decades without any rust,  unless they have been gouged,  drilled, shot,  etc.    But perhaps you are a young person,  where three decades is no time at all!

We all have our style.  Here always use metal pipe for all electrical stuff,  unless underground.   And use metal boxes for integrity of the shielding effect,  and have had good experience with metal boxes.

More Later,  Vic

westbranch

Jeez... look at the closest item I can find up here costs $262 Cdn..
https://www.homedepot.ca/en/home/p.50-amp-qo-hot-tubpoolspa-pack.1000165108.html

I guess it is the word SPA that costs!

Vic

Xizang said:

Vic said:

Hi Xizang,

Nice find   ...    So that will be good for two QO or one  QOB breakers with Ratings from 15,  to probably at least 30 Amps each.

The Tandem breakers  --  QOT  --  have NO DC rating,  as you probably know,  so  you could not really get four circuits.

AND,  yes,  SQ D is a Major brand  --  Schneider Electric bought SQ D some years ago.
I still spec and use SQ D panels,  boxes and breakers on projects,  and it is nice that CERTAIN QO ( ONLY QO,  QOB and QOU )  breakers will handle DC,  ONLY up to 48 VDC,  nominal  with Handle Ratings from 15 - 70 A,  ONLY.

Vic

I despise investing in and building things with materials that will quickly rust, corrode, rot or fall apart.  I love stainless, titanium, UV-stable plastics, etc.   Outdoors, the environment is trying to degrade everything back to its original state as quickly as possible.  And around the water, there's sunlight and salt and water ganging up on us.   So I was looking for a durable plastic enclosure that will resist rust and corrosion.

Do you know of a next-size larger plastic Square-D or other major brand non-metallic enclosure that might offer 4 to 6 spaces for a combiner box?   At a cheap price (for us cheapskates)?

Hi Xizang,

OK,  but just to be clear,  all or almost all of the MidNite Combiners are Aluminum,  and Powder-Coated.   Have never seen any corrosion on them,  or on the Outback Combiners which were essentially identical construction,  and preceded MN by eight-or-so years.

The MNEPV breakers are very inexpensive,  and these Combiners are designed for this Solar application:
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=9&productCatName=Combiners

QO  Loac Centers  and breakers are a bit of a work-around.

Just looked at Soladeck Combiners,  but the products shown all seem to be designed to be shingled into a roof.

FWIW,   Vic

vtmaps

Vic said:

and it is nice that CERTAIN QO ( ONLY QO,  QOB and QOU )  breakers will handle DC, 
ONLY up to 48 VDC,  nominal  with Handle Ratings from 15 - 70 A,  ONLY.

I thought that they were rated to 48 volts period, not 48 volts nominal.  A 48 volt nominal system could be over 60 volts during equalization.

--vtMaps

Vic

vt,  you are correct ...  the SQ D spec does not state "nominal",  is does state 48 VDC.

And,  yes,  I know well that a 48 V Flooded bank can operate,   even above 60 volts  --  the last EQ on one bank here showed 65.5 V at the CC.

Personally,  I   would not use QO breakers and Load Centers  for DC applications.

The MidNite (and Outback)  combiners,  boxes and breakers for DC applications  are inexpensive,   designed for the purpose,  and  there are a number of boxes and breaker sizes for almost any DC application.   And,  being designed for this specific use,  there is never a question about the suitability for these applications.

To me,  the only reason to use QOs,  is for those who are need an immediate solution,  so,  want to  buy something at the Home Center, because they feel they  cannot wait for delivery of MN products.    FWIW,      VIc

zoneblue

Here in NZ we use plastic for all AC switchbaords and distribution boards. However i think there is a reason that all solar combiners and discos are metal, with DC you have not only bigger current, but also DC arcs to contend with. We have seen several cases on this forum over the least 3 years of bus bar connections going high resistance and melting insulation to the point of failure. A plastic case will turn to a puddle of goo under any kind of fault condition like that. 

When i started this system, i also was price conscious, however experience quickly taught me that a sound nights sleep, knowing that your family is safe, is just so easily worth 70/120 bucks or whatever the combiner/disco is. And theres just so much more expensive parts of the system that doign teh BOS right doesnt materially effect the over all cost by any real margin.

Just a thought.

South Africa

I was very intrigued with the plastic boxes, till Zoneblue made a post.

Found this in a doc from the forum hosts:


In this doc: http://www.midnitesolar.com/pdfs/MidNite%20PV%20Combiners%20explained%20w%20diagrams.pdf

Dave Angelini

Unfair as apples and oranges 250 vdc and a nominal 48vdc  or 60 vdc. You are on the right track though. Plastic is never used above 150 vdc outside and I would never use it inside a structure. Standard good electrical practice for a century.

The XW and old SW load centers used the Square D type QOU  DIN rail but were pushing the spec on EQ for a 48 nominal.
The XW only uses type QOU on the AC side now of their XW distribution panel.
http://www.schneider-electric.us/en/faqs/FA119735/

zoneblue

I dont exactly understand what powered the change to plastic DBs here, it happened overnight about 20 years ago, same time as double insulation arrived in a big way. That we have 230V is i suspect a factor (less current, more shock risk). The flush boxes that hold powerpoints and light switches changed to plastic at the same time, and it does obviously remove a lot of grounding requirements.

However metal boxes as well as having some fire resistance, create more potential for circuit protection to pop upon loose wires, instead of flailing in t he breeze arcing.

Another thing to beware of plastic is the UV rating, as outside plastic doesnt last for ever.

If money is tight you cant really go wrong with a good ole  big baby box and some CBis.

http://www.solar-electric.com/misobigbabox.html
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/mnepv.html