Looking for a compact MC4 solar circuit breaker switch

[Prof Landsgrave]

I have a portable camping 200 watt solar system that I set up and tear down on a weekly basis. I'm looking to improve the system by adding a circuit breaker that I can use as a disconnect switch between the MPPT SCC and the solar panels. All my connections are mc4. Because it's a camping set up, I'd like the circuit breaker to be as compact as possible. Unfortunately, the smallest breaker I've found is still surprisingly large, at 2" x 2" x 4". I was hoping to find something much smaller, like 1" x 1" x 4" that would have mc4 lines for connection. After an hour of searching on Amazon and the web in general, I'm not having any luck.

I was considering using 2 inline circuit breakers, but the terminal connections on those things look terrible (it's just screwed into the wire) compared to a much more robust mc4 connection.

Can anyone recommend a compact circuit breaker (~30 amps 10 AWG) with a good terminal connection?

And one other question. For a solar power line, would it be sufficient to put a breaker / switch on just the positive line, or should the breaker always be on both the positive and negative lines? (I'm guessing the latter is better.)

Thanks,
Bill

 

[wpns]

Can you turn off or disable your SCC? Then you can disconnect your panels without any drama. Depending on the voltage, you might even want to have different connectors, MC4 is wonderful, but hard to frequently connect and disconnect.

Just interrupting the positive line should be fine.

 

[Prof Landsgrave]

Can you turn off or disable your SCC? Then you can disconnect your panels without any drama. Depending on the voltage, you might even want to have different connectors, MC4 is wonderful, but hard to frequently connect and disconnect.

Just interrupting the positive line should be fine.

Thanks for the suggestion. I'm using a Victron Energy SmartSolar MPPT 100v / 20a SCC. Before shopping for a circuit breaker, I checked the SCC manual to see if there was an option to disable the solar input lines from inside the SCC. I didn't see that option. The SCC can only disable battery charging.

I've been connecting / disconnecting the mc4 lines for 15 years. I've never had one fail, so they seem to hold up well to the frequent disconnects.

 

[wpns]

Thanks for the suggestion. I'm using a Victron Energy SmartSolar MPPT 100v / 20a SCC. Before shopping for a circuit breaker, I checked the SCC manual to see if there was an option to disable the solar input lines from inside the SCC. I didn't see that option. The SCC can only disable battery charging.

I've been connecting / disconnecting the mc4 lines for 15 years. I've never had one fail, so they seem to hold up well to the frequent disconnects.

Do you have a disconnect on the output of the MPPT? I suppose you could stop the battery charging and then disable the load, but I had a hard time getting the mood switch to work properly, and that seems like a lot of work if you could just flip a switch on the input.If it’s not drawing any power, then it’s OK to disconnect the input because there’s no current to draw an arc with.

Maybe it’s the arthritis that’s eating my hands, or maybe you have better MC4 connectors, but I have a hard time getting them apart.

 

[Prof Landsgrave]

Do you have a disconnect on the output of the MPPT? I suppose you could stop the battery charging and then disable the load, but I had a hard time getting the mood switch to work properly, and that seems like a lot of work if you could just flip a switch on the input.If it’s not drawing any power, then it’s OK to disconnect the input because there’s no current to draw an arc with.

Maybe it’s the arthritis that’s eating my hands, or maybe you have better MC4 connectors, but I have a hard time getting them apart.

That is a great suggestion. I don't use the SCC load line, so if I disabled battery charging, which I can do quickly through the app, then that would allow me to disconnect the line. I'll try that out. Thanks!

I should still follow through and get a fuse or circuit breaker for the solar line, just for safety. I don't have a fuse on the solar line, although there is a fuse inside the SCC.

 

[wpns]

That is a great suggestion. I don't use the SCC load line, so if I disabled battery charging, which I can do quickly through the app, then that would allow me to disconnect the line. I'll try that out. Thanks!

I should still follow through and get a fuse or circuit breaker for the solar line, just for safety. I don't have a fuse on the solar line, although there is a fuse inside the SCC.

IIRC the fuse is for the load, there's no battery or PV fuse. Of course, if you only have one (or two parallel) string, you don't need OCP on the PV side of things, solar panels are inherently current-limited.

 

[wpns]

Now that I think about it, you might be able to use the 4(?)-pin connector to enable/disable the load with a switch, but I had so much trouble with trying to control the output that I gave up.