Suggestions on fuse box and subpanel

Skysthelimit

New Member
I'm just about to start wiring up the array, 32 360 watt Renasolar panels in two parallel strings of 8. I plan on having a disconnect switch at the array for each parallel set, but I understand I need to fuse each string. Is there a box of some sort that can be purchased that will accept the 4 strings with a fuse for each string and also allow for them to be paralleled and then outputted to the disconnect? Any advice would be much appreciated.
 

Skysthelimit

New Member
Look for combiner boxes. An example:


MidniteSolar also makes "MNPVX" combiner boxes where X is the number of strings. I have an MNPV6. They have $15 breakers good to 150VDC rather than fuses.
Thanks for your reply. I'm a bit confused as to how this combiner box works? I see how it takes the inputs from the 4 strings, but it looks like there are exactly the same number of outputs.
 

HRTKD

Boondocker
@Skysthelimit, I concur with your question. What is being "combined"? In the above video, there is some combining taking place. For the second combiner box he showed, there are four inputs on each side (4 pos, 4 neg). The output side has only two outputs on on each side (2 pos, 2 neg). So you've gone from 4 to 2. Maybe you plan to run two solar charge controllers and that combiner box would work just fine.

If you wanted to run a single solar charge controller, you might take the two outputs from the combiner box to a set of bus bars and then go from the bus bars to the solar charge controller. Other combiner boxes have different combinations and outputs. It all depends on what you need.

When I was designing my system last year, the combiner boxes were more complexity than I needed. I wired my panels in series and took a single set of cables into a single solar charge controller.
 

sunshine_eggo

Happy Breffast!
OP, I linked the general page and would have assumed you would select the 4-1:


4 PV (+) enter from the bottom left and connect to fuses.
Red wires on the top of those fuses join to a circuit board joining the wires.
One wire comes out of that circuit board into the top of the left breaker.
Single combined PV+ comes out the bottom of the left breaker.

Repeat for (-) on the right side.

Maybe the MNPV4 will be clearer:

 

Skysthelimit

New Member
I probably wasn't clear...I'm currently assembling my array. It consists of 32 360 watt panels. I have 2 5kw Growatt inverter/chargers. I will parallel 2 strings of 8 panels into each inverter. I'm looking for a box that will allow me to combine 4 strings into 2, have fusing for each string, and room for 2 disconnect switches so I can perform maintenance on one parallel set of panels while the other parallel set is still in operation. I'm probably asking for too much, but that's the ideal scenario. Alternatively, I'll take the output from the box that can combine the 4 strings into two, send those 4 wires into two IMO switches and from there into the conduit, some 45', where it ends up in my cement vault, where the inverters, batteries, subpanel, midpoint transformer, and other associated stuff is.
 

Skysthelimit

New Member
OP, I linked the general page and would have assumed you would select the 4-1:


4 PV (+) enter from the bottom left and connect to fuses.
Red wires on the top of those fuses join to a circuit board joining the wires.
One wire comes out of that circuit board into the top of the left breaker.
Single combined PV+ comes out the bottom of the left breaker.

Repeat for (-) on the right side.

Maybe the MNPV4 will be clearer:

Unless I'm mistaken, it looks like the MNPV4 is designed to combine 4 strings into 1. That's not what I'm trying to do. Thanks anyway.
 
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