Help figuring solar panel breakers/disconnects?

[GregM]

I will be wiring 8 panels per string. (4 strings)
Each panel is 370w
Each string would be 328v at 10.92 amps (series).

Would like a 4 string circuit breaker/disconnect.
Will run from there to the 4 inverter inputs.

 

[kennyb]

SI16-PEL64R-4 should do the trick for a disconnect.

If you want to roll your own enclosure just the switch with panel mounted knob is: SI16-BMDC64R-4

 

[GregM]

Thank you.

 

[timselectric]

FYI: you will need two of those switches. Each can take care of two PV circuits.

 

[timselectric]

For 4 circuits, you need the SI16-BMDC64R-8.

 

[Bluedog225]

I’m needing during like this myself. Still leaning this part of the systems.

Is the product you recommend a “switch/disconnect?” And is that aka an “isolator.”

Reading this.

https://www.farnell.com/datasheets/2163326.pdf

Thanks

 

[Bluedog225]

Edit- and what kind of box does that mount in? Or is it outdoor rated?

 

[timselectric]

Is the product you recommend a “switch/disconnect?” And is that aka an “isolator.”

I didn't recommend it. But yes, it is a PV disconnect/isolator.

Edit- and what kind of box does that mount in? Or is it outdoor rated?

It can be purchased with the included outdoor rated enclosure.
But, looks like some models will fit in any standard din rail enclosure.

 

[Bluedog225]

Got it. Thanks

 

[GregM]

For 4 circuits, you need the SI16-BMDC64R-8.

Guess I assumed you would break the positive and run the negative on by to the inverter.

 

[timselectric]

Guess I assumed you would break the positive and run the negative on by to the inverter.

You are required to break both positive and negative.
You only need to provide OCP (Over Current Protection) for the positive.
But a disconnect must open (break/ turn off) all ungrounded conductors with a common handle.

 

[GregM]

So with that information I started looking at DC circuit breakers they are doubles so they can handle both positive and negative.
They are 16amps and 500v ea, which should handle the four strings that are 10.9 amps and 328 volts each.




To hold them I have found a metal "Din Rail box" which will hold the 4 breakers



How's that sound?

 

[timselectric]

That's exactly how I would do it.
I'm not familiar with that breaker brand. So, I don't know how well they perform. Or if they are listed. (If needed)

 

[GregM]

Thanks

 

[kennyb]

FYI: you will need two of those switches. Each can take care of two PV circuits.

Good catch thanks. Should have been the -8 model.

 

[Bluedog225]

Currentconnected.com has this. I think it serves the function.

Solar PV DC Quick Disconnect Switch | Current Connected

Discover our Solar PV Quick Disconnect Switch with user-independent switching action, ensuring a lightning-fast break/make action in just 3ms!

www.currentconnected.com

 

[jamiegreen]

So with that information I started looking at DC circuit breakers they are doubles so they can handle both positive and negative.
They are 16amps and 500v ea, which should handle the four strings that are 10.9 amps and 328 volts each.
View attachment 179366



To hold them I have found a metal "Din Rail box" which will hold the 4 breakers

View attachment 179368

How's that sound?

I'm very wary of these cheaper DC circuit breakers.. although its their job, they don't like being switched off under load, at least not too many times. There are so many videos of them letting out the magic smoke. There must be a reason the branded ones (Schneider etc) are so expensive. I prefer the route of mc4 inline fuses for each string or a fused combiner box, and then DC rotary isolator(s) for disconnecting the arrays, like what Bluedog posted.

 

[GregM]

I'm very wary of these cheaper DC circuit breakers.. although its their job, they don't like being switched off under load, at least not too many times. There are so many videos of them letting out the magic smoke. There must be a reason the branded ones (Schneider etc) are so expensive. I prefer the route of mc4 inline fuses for each string or a fused combiner box, and then DC rotary isolator(s) for disconnecting the arrays, like what Bluedog posted.

Do you have a brand you would recommend?

 

[Dynoman]

Do you have a brand you would recommend?

MidNite Solar is considered a good brand.

MidNite Solar Alternative Energy Products: E-Panels to Inverters

MidNite Solar offers a large variety of alternative energy products from E-panels to charge controllers and inverters.

www.midnitesolar.com

If not sure what to get for your application give them a call.

 

[jamiegreen]

Do you have a brand you would recommend?

Breakers or rotary switches?
Rotary switches I don't have too much preference, obviously not the cheapest, but the way they work and the much bigger distance between contacts drastically reduces the risk of arcing and welding contacts together in comparison to breakers.

As for breakers.. I couldn't really, say I have a GEYA brand breaker in my system as well as fuses and rotaries, Its not the absolute cheapest but far from high end, I would never use it to isolate solar power when in good sun conditions, and nor would I trust it as a standalone protection device without any additional fuses, and that's with me running around 150v of PV.