Circuit Breaker Instead Of 12v Switch?

[HRTKD]

I need to put in a couple 12v switches close to my batteries. My component compartment is starting to get crowded, it's getting untidy. I was looking at surface mount switches, something I can attach to the plywood on the wall. The selection is a bit limited. Maybe I'm not looking using the right terms. Most switches want to be installed in a panel, which I don't have. The switch does not need to be illuminated. SPST or SPDT would work. The switch needs to handle 20 amps. The load shouldn't ever be that high, closer to 12 amps. But I don't want to burn out the switch.

I have a DIN rail with plenty of room on it. I got to thinking of using a DC breaker as a switch on the DIN rail. Circuit breakers are relatively inexpensive and having the over current protection would be a plus. Good idea? Bad idea?

 

[gerrymac58]

Well my experience with 12 volt circiut breakers hasn't gone well. I needed the same a switch and fuse in one next to batteries. My 300 amp circuit breaker failed. Took awhile to work out what was causing the problem.
I am living in Australia we don't have 12 volt circiut breakers that attach to a din rail. They are quite separate. 12 volt is attached to bus bars here.
My limited knowledge is that 12 v continuous current can be used in alternating current but not vise versa. DC current can potentially jump an AC switch. DC switches and circuit breakers are clunky for a reason. DC current has tremendous pressure/force behind it.
Hope this is useful.
Gerry

 

[HRTKD]

The circuit breakers I bought for between the solar panels and solar charge controller ended up being AC, not DC like I thought. I bought the correct circuit breaker after the fact. I'm trying to avoid making that mistake again.

Using a circuit breaker in this situation is a bit like using a sledge hammer to drive tacks.

 

[HRTKD]

This circuit breaker is along the lines that I'm thinking of.

20 AMP 150VDC DIN RAIL MOUNT BREAKER

It being sold on the site that @SolarQueen works for is an added benefit.

 

[gerrymac58]

This circuit breaker is along the lines that I'm thinking of.

20 AMP 150VDC DIN RAIL MOUNT BREAKER

It being sold on the site that @SolarQueen works for is an added benefit.

Looks neat and tidy. Low amps for DC I just use blade fuses for low amps and fuse to wire rating, unless you are trying to protect an unprotected appliance.

 

[chrisski]

his circuit breaker is along the lines that I'm thinking of.

20 AMP 150VDC DIN RAIL MOUNT BREAKER

It being sold on the site that @SolarQueen works for is an added benefit.

I use those circuit breakers, 10 amp and 30 amp, on a DIN rail. I use this as on off switches when starting, stopping solar for the day and also to trouble shoot.

I have two 10 amps for my two strings of roof mounted panels mounted on DIN rails in a Midnite solar breaker box. For my portable panels, I have in a junction box on DIN rails a 30 amp dual pole polarized breaker after they are combined on DIN rails, and in a seperate junction box four 10 amp circuit breakers four each solar panel.

I take this to mean they can be used as switches "These breakers are rated to break the full rated load at the rated voltage repeatedly." I am way underneath the 150 VDC for my single pole10 amps and way underneath the 250 VDC for for my dual pole 30 amps.

I had difficulty finding a DC rotary switch. I found 3 position, two throw 65 amp AC switch which was exactly what I wanted, and I contacted Blue Sea about it, and they contacted Krause Naimer the maker of the switch and they said " that is will work for DC also." I still did not feel comfortable about it.

Someone recommended Schneider-Electric DC switches, but those were priced at $165 each for what I wanted and the link I was sent no longer works.

Instead of a 65 amp switch someone recommend I consider solid state relays here: https://www.digikey.com/en/products/filter/solid-state-relays/183?s=N4IgTCBcDaICIGEAEBlFAlEBdAvkA

 

[HRTKD]

I use those circuit breakers, 10 amp and 30 amp, on a DIN rail. I use this as on off switches when starting, stopping solar for the day and also to trouble shoot.

I have two 10 amps for my two strings of roof mounted panels mounted on DIN rails in a Midnite solar breaker box. For my portable panels, I have in a junction box on DIN rails a 30 amp dual pole polarized breaker after they are combined on DIN rails, and in a seperate junction box four 10 amp circuit breakers four each solar panel.

I take this to mean they can be used as switches "These breakers are rated to break the full rated load at the rated voltage repeatedly." I am way underneath the 150 VDC for my single pole10 amps and way underneath the 250 VDC for for my dual pole 30 amps.

I had difficulty finding a DC rotary switch. I found 3 position, two throw 65 amp AC switch which was exactly what I wanted, and I contacted Blue Sea about it, and they contacted Krause Naimer the maker of the switch and they said " that is will work for DC also." I still did not feel comfortable about it.

Someone recommended Schneider-Electric DC switches, but those were priced at $165 each for what I wanted and the link I was sent no longer works.

Instead of a 65 amp switch someone recommend I consider solid state relays here: https://www.digikey.com/en/products/filter/solid-state-relays/183?s=N4IgTCBcDaICIGEAEBlFAlEBdAvkA

The simple DC circuit breaker is looking better and better. If the circuit breaker is a sledge hammer on a tack, then those solid state relays are like using a nuke to take out a pesky fly.

 

[BiduleOhm]

Well, technically a breaker isn't made to be used as a switch. You can use it to disconnect something from time to time but it's usually a bad idea to use one as an everyday switch as then it can fail quickly.

So the question is really how many times do you think you'll open/close it per month for example?

 

[HRTKD]

Well, technically a breaker isn't made to be used as a switch. You can use it to disconnect something from time to time but it's usually a bad idea to use one as an everyday switch as then it can fail quickly.

So the question is really how many times do you think you'll open/close it per month for example?

Ideally, the "switch" would be used maybe four times a year, if that. Once the RV is winterized, it's too cold for water, so it's too cold for unheated batteries. I would turn on the battery warming system at that time. In the spring, when I de-winterize the trailer, I would turn the system off.

There are some strange years when the trailer gets winterized early due to a freak freeze and then de-winterized a week later when I go camping.

 

[BiduleOhm]

Then a breaker is perfectly fine

 

[HRTKD]

This circuit breaker is along the lines that I'm thinking of.

20 AMP 150VDC DIN RAIL MOUNT BREAKER

It being sold on the site that @SolarQueen works for is an added benefit.

This is the breaker that I went with. I had intended to post some relevant information about it in this thread, but did it in a different thread instead. The key thing that I posted in the other thread is that the breakers appear to be polarized.

Link to the post in the other thread, including pictures: https://diysolarforum.com/threads/solar-circuit-breaker-for-24v-setup.15406/#post-173068

 

[FilterGuy]

I am late to the discusion, but here is an option for mounting a toggle switch on a DIN rail. You might be able to use it for surface mount too.
https://www.alliedelec.com/product/eaton-cutler-hammer/m22-ivs/70057787/

 

[HRTKD]

I am late to the discusion, but here is an option for mounting a toggle switch on a DIN rail. You might be able to use it for surface mount too.
https://www.alliedelec.com/product/eaton-cutler-hammer/m22-ivs/70057787/

View attachment 29222

Yep, that would have worked too.

 

[Zil]

Blue Sea has surface mount breakers designed to use as a switch. Lower ampere DC. https://www.bluesea.com/products/category/14/32/Circuit_Breakers/285-Series

 

[HRTKD]

I didn't have room for a surface mount. The DIN rail had room. The DIN rail breaker ended up being a lot less expensive also. Otherwise, I do use the Blue Sea surface mount breakers elsewhere in my system.

 

[Zil]

Quote you; "I was looking at surface mount switches, something I can attach to the plywood on the wall. The selection is a bit limited."

 

[HRTKD]

Quote you; "I was looking at surface mount switches, something I can attach to the plywood on the wall. The selection is a bit limited."

I was looking at dinky little surface mount switches, about 20% the size of the Blue Sea breakers. I should have included a size for context.

 

[Freep]

There are some strange years when the trailer gets winterized early due to a freak freeze and then de-winterized a week later when I go camping.

That happens to me almost every year but it's usually because we need a break from winter and drive down to the desert for a few weeks. Filling the fresh tank with water in the middle of a Wisconsin winter is not fun.