Combiner Box at PV Array or IMO Disconnect???

[WattAboutThat]

QUESTION OF THE DAY…

Setup:
2 x 18kPV Inverters
60 385W Canadian Solar Panels
wired as 6 strings of 10 panels each string

Intent:
To wire one string to each mppt
(not using parallel ability of mppt 1 for now)
intend to buy 20 more panels later to make
use of mppt 1 parallel

each mppt max is 15A at inverter
each string is about 11A from panels
(mppt 1 max paralleled is 25A)

QUESTIONS:

Question One (1):

Pros and Cons
of using a Watts247 4 string to 2 out combiner box

https://watts247.com/product/solar-panel-combiner-box-4-circuits-to-2/

is this box reliable?

i intend to use 2 strings per combiner box
one box will only get 1 string leaving
availability to add a fourth string in future
for mppt 1 paralleled port in inverter

no strings will be combined
the only intent it to get
fuse, breaker, spd, for each string
so i will not be using 2 of the pv inputs on each box
essentially it is a single string combiner
(even though not combining)
and 2 strings per box)

Please Advise?


Question Two (2):

The panels will be approximately 100 feet
or less from Solar Control Room with inverters.

I also intend to have IMO Disconnects.
Two strings per disconnect (one not used but reserved for mppt 1 parallel string later).

I am thinking to place the
IMO Disconnects out at the Panels,
and placing the Combiner Boxes
inside the Solar Control Room.

But I could reverse this
so combiners are at array
and IMOs are in control room.

I understand the combiners should be prior to wire run to protect wires, so therefore argument is to place at array, but my gut wants to put them in the control room.

What are the pros and cons I should consider
to avoid any or most issues, I may not be considering?

As always, your advice is greatly appreciated!

 

[timselectric]

Intent:
To wire one string to each mppt

You don't need a combiner box, if you aren't combining strings.

 

[SignatureSolarJames]

just IMO I.M.O

 

[Zapper77]

Grid connected w/feedback?

 

[Zwy]

QUESTION OF THE DAY…

Setup:
2 x 18kPV Inverters
60 385W Canadian Solar Panels
wired as 6 strings of 10 panels each string

Intent:
To wire one string to each mppt
(not using parallel ability of mppt 1 for now)
intend to buy 20 more panels later to make
use of mppt 1 parallel

each mppt max is 15A at inverter
each string is about 11A from panels
(mppt 1 max paralleled is 25A)

QUESTIONS:

Question One (1):

Pros and Cons
of using a Watts247 4 string to 2 out combiner box

https://watts247.com/product/solar-panel-combiner-box-4-circuits-to-2/

is this box reliable?

i intend to use 2 strings per combiner box
one box will only get 1 string leaving
availability to add a fourth string in future
for mppt 1 paralleled port in inverter

no strings will be combined
the only intent it to get
fuse, breaker, spd, for each string
so i will not be using 2 of the pv inputs on each box
essentially it is a single string combiner
(even though not combining)
and 2 strings per box)

Please Advise?


Question Two (2):

The panels will be approximately 100 feet
or less from Solar Control Room with inverters.

I also intend to have IMO Disconnects.
Two strings per disconnect (one not used but reserved for mppt 1 parallel string later).

I am thinking to place the
IMO Disconnects out at the Panels,
and placing the Combiner Boxes
inside the Solar Control Room.

But I could reverse this
so combiners are at array
and IMOs are in control room.

I understand the combiners should be prior to wire run to protect wires, so therefore argument is to place at array, but my gut wants to put them in the control room.

What are the pros and cons I should consider
to avoid any or most issues, I may not be considering?

As always, your advice is greatly appreciated!

That is money that doesn't need to be spent. I answered your question about combiner box in this thread: https://diysolarforum.com/threads/s...-for-fuse-breaker-lightning.63257/post-788334

If you really have your heart set on a 4 to 2 combiner box, I have a brand new one still in the box in my back shed that you might get bought at a discount. No need for combiners with high PV voltage SCC's and larger panels. Most larger panels will put you over on amps when paralleling strings. I'll probably rework the box for single strings. It is a nice box but I built what I have for $130.

 

[RibarRanch]

Good info….

 

[SilverbackMP]

Schneider makes all weather and 600v DC rated disconnects. I think they are three pole so you’d need two. I don’t think a fuse is required for all series strings under the NEC or other best practices but other folks can correct me.

 

[timselectric]

Two strings or less. No fuses required.
Three strings or more. Fuse required for each string.

 

[SilverbackMP]

Two strings or less. No fuses required.
Three strings or more. Fuse required for each string.

For paralleling three or more strings in series together. Correct?

But six individual strings only in series would require none. Correct?

 

[timselectric]

For paralleling three or more strings in series together. Correct?

But six individual strings only in series would require none. Correct?

Correct
If each string is connected to its own SCC, no fuses required.
I was going on the thread title "Combiner box".
I probably should have taken the time to read the conversation.

 

[SilverbackMP]

Correct
If each string is connected to its own SCC, no fuses required.
I was going on the thread title "Combiner box".
I probably should have taken the time to read the conversation.

Gave me a bit of a pause cause I didn’t fuse mine. Just the MidNite 600v SPDs.