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Tomzn DC Circuit Breakers (Yellow vs Blue)
(11-25-2019, 06:25 PM)Crimp Daddy Wrote: Yes, I agree that bi-direction would be ideal, especially for certain conditions where flow could be reversed, like when charging.

FYI, as the breaker trips, polarity specific breakers expect the electric arc to "flow" in just one direction, and the mechanism to interrupt/extinguish the arc is designed to handle just that direction. Install that breaker the wrong way in a sufficiently high voltage/amps system, and the arc will keep going indefinitely, likely resulting in a fire. See the YouTube video for a very dramatic demonstration.

Polarised Solar DC Circuit Breakers - Reverse Polarity

Crimp Daddy, Korishan, daromer And 1 others like this post
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Excellent video.  At this stage I feel I have a good understanding of polarity and why it matters.  I can certainly see the value in a bi-directional DC breaker.

What I still want clarification about is the comments in my last post about wiring a breaker in series.  Even the breaker in the video you posted was wired in series, which would be a positive branch breaker only.  It conflicts with how mike has wired his, even though that also appears correct with the load wired across the two bottom posts.  While its right, it might cut the DC rating in half.

Even my ABB shunt trip has instructions to wire DC in this manner.

Personally I feel the 600VDC rating on the Tomzn only applies when wired in series, which is what I set out to try and confirm.
You wire it in series over like that to have a wider gap and tollerate higher voltages. Or atleast thats the most common. Like a breaker do 400VDC 1 turn and 600VDC 2 turns.
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(11-25-2019, 06:25 PM)Crimp Daddy Wrote: I have noticed some breakers wired in series... usually on two pole+ breakers.  EATON and MIDNITE both have different voltage ratings depending on how its wired.  EATON for example is 48v, or 96v when in series.  Here are some visual examples.

I was curious of the Tomzn rating of 600VDC was when tired in series... it appears both of these would be valid ways of connecting it. 

Provided you use double-throw breakers (ie. Left pole part and Right pole part are physically synced) and in the same electrical circuit, either wiring has the same double-strength electricity/arc cutting effect.  It's just changing the order of the parts - it makes no difference to the electrons.

PatternA (right pic):    [PV+] -> [BreakerLeftPole] -> [SolarCharger] -> [BreakerRightPole] -> [PV-]
PatternB (left pic):    [PV+] -> [BreakerLeftPole] -> [BreakerRightPole] -> [SolarCharger] -> [PV-]

So in both PatternA and PatternB, BreakerLeftPole and BreakerRightPole are wired in series, just in a different order.
I think most people prefer PatternA, as this physically disconnects from both PV- and PV+, and would probably be safer should the panels have some sort of grounding fault.
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I have Tomzn breakers from 3A to 125A in 1 pole to 4 pole configurations.. my conclusion so far... use the lower rated units only (upto 63A).

I have tried tripping a single pole 100A unit by plating around burning 10mm2 cable with way over 300A spikes and even once had a slight accident of a short for a second (enough to heat up a 10mm2 cable to melt the inner plastic) and the 100A breaker did not trip... that was concerning.

For higher amps use a 4 pode device (4 x 20A) to get an 80A breaker for example, rather than going for a single pole device at high amps.

Don't run them near 100% (of any breaker for that matter) as the heating effect will have a more significant effect on contact resistance (heating and cooling cycling loosening the joints) and will end up heating up more and burning out.

I have posted some images on a previous thread where I stripped some down as they do have an issue in that when they are tripped after a serious fault the contect surfaces seem to be affected quite a bit (relatively) and the units would then trip if your using them at high loading levels.

I have had some AC rated devices arc on about 160V DC continuously until they burn out, fortunetely they don't seem to set fire or at least the 4 that I have had burn out in various ways have not shown significant enought heat damage to show any flame.... that said don't mount them on a wooden board or at least have a good air gap behind them..

Random rants done.

The DC units may have larger contact separation in addition to the tiny magnet that is installed to deflect the polarised arc..

Lat one.... with polarised breakers and battery packs you tend to end up with a breaker at each end of the wire... to cope with fault origins at either end.
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
Sometimes I get impressed with how fast stuff from China actually gets here...  I ordered a small assortment of breakers to play with.


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