Dc breakers and inline MC4 fuse

[WorldwideDave]

To prototype my system, I used an in-line fuse before going to the solar charge controller. Now I will have a DC disconnect rated at 1000 A for 300 W of solar panels. Do I still need the in-line fuse and if so, would it go Before the disconnect/breaker or after it? I feel like the DC breakers serve the same purpose as the in-line fuse so maybe it’s not required?

 

[Shimmy]

To prototype my system, I used an in-line fuse before going to the solar charge controller. Now I will have a DC disconnect rated at 1000 A for 300 W of solar panels. Do I still need the in-line fuse and if so, would it go Before the disconnect/breaker or after it? I feel like the DC breakers serve the same purpose as the in-line fuse so maybe it’s not required?

The fuse is only needed if you have parallel strings; the PV panels are current limited.

 

[WorldwideDave]

I have two panels connected together with a Y adapter mC4. I think they are in parallel together. Are you suggesting that I put it in line fuse before the adapter, or after the adapter and before the DC breakers?

 

[Shimmy]

I have two panels connected together with a Y adapter mC4. I think they are in parallel together. Are you suggesting that I put it in line fuse before the adapter, or after the adapter and before the DC breakers?

A fuse isn't needed for two in parallel; you don't need circuit protection until you have more than two.

 

[Crowz]

Circuit breaker A 1500V 32A Photovoltaic DC Isolator Solar Switch makes a wonderful disconnect for maintenance purposes. I use mine all the time.

I used to use breakers till they started shooting sparks. Now I use these as disconnects :

 

[WorldwideDave]

Thank you. My disconnect looks like two small breakers. I got everything wired up tonight and will test the system tomorrow and report back.

 

[WorldwideDave]

The system I built is working good. Will post pictures later.

 

[BarracudaBob]

I have had a couple of inline fuse fail due to heat. The plastic becomes brittle and when I touch them they break. Already have a similar disconnect. Time to add a breaker.