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Forum Index : Solar : Inline mc4 fuse
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Sorry George but you are WRONG! An AC breaker relies on the 0 crossing of the wave to extinguish the arc. When you turn off DC the current does not drop to 0 but continues and makes an arc just like you described. Turning off both positive and negative together just means 2 arcs and twice the problem. DC Breakers have a large gap and a magnet to pull the arc out of the breaker contacts. AC Breakers don't have the magnet and this is why they are not to be used with DC. The fire will start from within the breaker itself nothing to do with the wires they are simply delivering the power to the arc. You are at risk of having a fire, I am just trying to give you some friendly advice, you are taking a big risk with your home and the lives of the people that live in it. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
I appreciate the warning and the sentiment behind it but please understand, I have seen nothing to make me believe it. I don't mean that to be a smartarse, I mean it sincerely and honestly. This is a perfect example of a saying of mine, you can tell people things but getting them to believe it is a different thing. This is where I find myself with this. Could you suggest the parameters of a test like the vid you linked to I could setup to demonstrate and enlighten myself of how these AC breakers can fail as you describe? I have 5+ Kw of panels at my disposal I can easily tap into so if you could tell me what I have to do to light a couple of AC breakers up, i'd be happy to make the investment for the learning value and a great YT vid! It would be good to demonstrate to others whom may also be ignorant and disbelieving like myself. As I said, I have done this repeatedly with around 2.8 Kw and a lot more load going through the Ac breakers I have and there hasn't been so much as a fizz. I don't want to be taking a position based on an ineffective parameter when possibly just a bit more power may make all the difference. Knowing the facts is more important to me than being wrong so I'm interested to see this first hand and change my mind. What would I have to do to light some AC breaker up to see what you are talking about and educate my ignorant self? You may be please to know that the AC breakers I am using are for the systems on the shed. I now have 3 or 4 ( can't remember) proper dial type isolators from the used systems I bought. I am starting to install panels on the house and did intend to use these isolators on the 2 arrays I plan to put up. One will be 5 Kw and the other 4. I have also arranged for a sparky to come put in a couple of heavy duty Circuits for the solar and will over rate that cable significantly being I can afford to as the cable run won't be too long and the guy is happy to sell me the cable by the meter at cost. We are looking at 10mm to do a separate circuit for each inverter. Overkill but if I want to add more panels later, I will have the headroom to do so. Still will have more than half the roof available. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I was actually looking at making a 'solar powered stick welder' once I start building the new place- basically solar panels attached to a welding holder LOL Most stick welders are between 30-60vdc, varying the current from 30a up to a hundred or more for things like truck chassis welding So as a panel is a constant current source (like the better stick welders), I was thinking along the lines of having 10 or so 180w panels in parallel as a offgrid welder.... Might work, might not but be fun trying |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Wiring up 10 panels in Parallel sound like a real pain in the backside. You could put each or every 2nd one on a breaker to give yourself some amperage control. Something I was thinking to give a go was making Chlorine. I believe one takes a salt water soloution and passes a current through a couple of plates to convert the salt to Chlorine ( and a couple of other things helpful for cleaning). |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Well no wonder it's confusing, some breakers are manufactured bottom feed, others top feed and others have polarity markings top and bottom. Read here Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
My 200A MIG welder operates under 30VDC but they are constant voltage rather than constant current like a stick welder. You can buy a inverter stick welder on Ebay for under $100 delivered, with a few mods the make good battery chargers also. Here is a demonstration VIDEO of the difference between breaking a AC circuit and a DC circuit. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Mark you use the correct polarity on the side that supplies the current. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
I can't see why the breaker terminal orientation would make much difference anyway. Looking at the the breaker boxes and the isolators I have got with the used systems I have bought, the penetrations for the cable are all from the bottom and the wire goes up in the housing and to the top side of the breakers. Can't see any need on the boxes I have to have to come in or out from the top. Go through the bottom side by side and take the cable to the other side of the breaker internally leaving the top of the switch box sealed so the water can run off and not have a way in. Mad, did you see my question about creating the parameters for an AC breaker burn demonstration? Nice and sunny here today and I'm not going anywhere so would be interested to give it a go. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
To be honest George I can't be bothered if you think you can get away with it good luck to you. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Sorry, that's a complete and utter cop out and you know it. If you thought you would be proven right when push came to shove, you'd have no hesitation in saying "run this many volts at this many amps through this size breaker and do this" to prove your position. That's always the test I use with fearmongering and excessive safety warnings, rather than avoid, actually Create the problem and see what happens when you do. It never is at all like the over hyped warnings predict or stands up to the parroted mantra's. I'd do a test myself but without instructions, Know whatever I do would be deemed flawed with an endless myriad of manufactured flaws in the test when it didn't go up in smoke. You are a far more knowledgeable and intelligent fella than I am mad but that does not mean you cannot be wrong or overly pedantic about some things. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
DC breakers aren't dear so why not just use them? here is an example Cheers Caveman Mark Off grid eastern Melb |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
They are good quality breakers, have used them myself, have quite strong blowout magnets inside to prevent arc's forming; unlike some of the other chinese brands marked as suitable for DC, but have no magnets inside at all. New regs here in NZ means they are not allowed, as your average electrician doesnt know how to wire them up. However nothing wrong with them if wired correctly. Mike |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
If I need any more, I will get some. For the moment I'm OK with the isolators I have. With this thread in mind, Today I went up the back and again with 2.8 Kw going through them, I turned off the AC breakers I have ( Wired through both poles) Several times. Again, Not peep out of them. If I saw anything to make me think they were not safe, I would change them. As said, they aren't exy but I have seen nothing to make me think wired up as I have them there is anything wrong with using them. Again, I am NOT using them as just switching one side but as 2 poles breaking both outputs at the same time. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
some brands have an identical innards in their AC breakers, like noark and sometimes they get sold real cheap in bulk. I'm confused, no wait... maybe I'm not... |
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