DMerciful:
Wish these clouds could disappear...affecting my harvest

kiekie1:



DC circuit breaker, like their name suggests, is used for the protection of electrical devices that operate with direct current. The main difference between direct current and alternating current is that in DC the voltage output is constant, while in AC it cycles several times per second.

Monlo:


@Dmerciful,how much did u acquire this meter.I think i may need one to combine with my Epsolar mppt CC,so i can be seeing the input/output parameter at the same time.Tnks

Monlo:


@Dmerciful,how much did u acquire this meter.I think i may need one to combine with my Epsolar mppt CC,so i can be seeing the input/output parameter at the same time.Tnks

DMerciful:
Whatsapp me....don't want to interfere with people's business

DMerciful:
They are available on aliexpress.com...just search for two pole breakers. You van also get multiple
https://www.aliexpress.com/item/FZ47LE-63-C63-AC-400V-63A-Two-Pole-On-Off-Switch-Mini-Circuit-Breaker-4000A/32332213418.html?spm=2114.01010208.3.102.4oxvv9&ws_ab_test=searchweb0_0,searchweb201602_4_10065_10056_10068_10055_10054_10069_10059_10078_10079_10073_10017_10080_10070_10082_10081_421_420_10060_10061_10052_10062_10053_10050_10051,searchweb201603_7&btsid=23ee2156-1dc8-431f-ad38-7efa937ad056

mank1234:


The link posted is for ac breaker. I actually have 2 DC circuit breakers, each is double pole with one terminal marked +ve the other terminal -ve. One is 32A, the other 63A. Was wondering if there's a way of linking the two to trip at the same time.

I'm using the 32A between solar and CC, 63A between battery and CC. From previous warnings, it's possible for the 63A to trip and destroy the CC. So I'm wondering if the two breakers can be made to trip simultaneously if there's fault.

DMerciful:
I understand but how does the breaker differs apart from name? What happens if you use AC breakers for DC applications?

DMerciful:
U can use clamp to link the two breaker lever or use solid guy and a bar to link them to get her. Sincerely, I don't see anything between AC n DC breaker unless someone educate me. For now I use AC breakers n no lele

mank1234:


The difference is majorly at the point of extinguishing the arc formed during closing and opening of the contact. With AC, the arc is of short duration since the current changes direction 50 times per second. In DC, current does not changes direction so the arc is longer. If you use AC in place of DC,as the components is not made to eextinguished long duration electric arc.

Arc in layman language is the fire or spark you see when you touch two wires together. It also happens inside the breaker but you won't notice it because it's immediately extinguished.

mank1234:


May be I'll convert to a single four pole AC breaker after all the circuit breaker is not intended to be put ON and OFF frequently. Please reconfirm that you are using AC breakers with no issues. Thanks

DMerciful:
I am using AC breakers with no issues.

efuro:
for now I use AC breaker too. I gather from an electrician dat AC breaker will burn too quickly but a least I have a breaker btw my PV and cc. no breaker btw battery and 60A fangpusun mmpt

battleaxe:
Again, this is not recommended!

Look online and you can see several stories/experiences in this.

Solar depot had a number of DC breakers(can't recall seeing any DP though).

It's easier to take certain risks when you know a system inside out. If you don't, biko buy the proper parts.

efuro:
for now I use AC breaker too. I gather from an electrician dat AC breaker will burn too quickly but a least I have a breaker btw my PV and cc. no breaker btw battery and 60A fangpusun mmpt

DMerciful:
How is this fagpunsun controller? Does it have data logs? How is the performance? Can you show pics of readings

ojesymsym:
Could you explain d design, process flow, d constituents and probable cost estimates for each?
Thanks in advance.

efuro:


of course. just like u. weather has been punishing me. it just 600w combination of 2 poly, 2 mono of 150w

DMerciful:
D sun later picked up here and I had a good harvest from my 1000W system.

DMerciful:
For those who really need DC breakers
https://www.aliexpress.com/item/2P-63A-DC-440V-Circuit-breaker-MCB-for-PV/623939178.html?shortkey=vyU73ERn&addresstype=600

efuro:


kool! my oga, I will get there one day. I like kiekie's YouTube PV arrays

@ DMerciful I do not mean to be rude oooo
my kool means cooool. NEPA will jealous ur production. imagine ur total kilowatt. if ur to sell like given estimated bills, bankers will be ur best Friends

efuro:
great frankee! I only called u for price of DC breakers. 15A, 30A & 60A.

I will expand soon. recession is bits hard.

efuro:
older pix

Obimind1:

Is ur set up a 24v set up? If yes, how did u connect those 4 batteries without having to deal with the batteries not being unequally charged?

DMerciful:
Learnt something now...double pole breakers ensures the PV and battery are disconnected simultaneously thus avoiding d risk I mentioned earlier which is battery side tripping and PV side still energised. This makes more sense.

efuro:
for now I use AC breaker too. I gather from an electrician dat AC breaker will burn too quickly but a least I have a breaker btw my PV and cc. no breaker btw battery and 60A fangpusun mmpt

bigrovar:

Double pole breaker is also not a perfect solution ooo.. it comes with its own issues

1 Sizing: One of the most important consideration for your breaker system is getting the right size for the job. Too small and u get lots of false positives (if u are lucky) or it just don't work. Too large and you have a weak protective system.

Now note that on the PV output to cc voltage is usually higher than current.. your breaker should reflect that. On the cc to battery side amp is higher than voltage breaker should also reflect that.

If you use a double pole breaker as a one breaker rule them all situation then you have to still prioritise which device is worth saving the most. And 9 out of ten times u find out it is the battery cc side that's most important. The breaker in a double pole scenario should be sized with a bias towards protecting the battery from shorting
(Which in a way defeats the purpose of having double pole system anyways
NB: If your panel voltage and amp is close to that of your cc output then this won't be an issue.

2 second issue with a double pole system is the connection sequence. Recommended connection sequence for a PV battery CC situation is .. battery to PV first.. wait for CC to boot and load ( usually tiny few seconds) then connect PV to cc. Disconnect sequence is the reverse. Disconnect PV then disconnect battery. A double pole system makes nonsense of this arrangement as it turns on the PV into and the Batt input at exactly the same time. Your CC would be taking in close to 90v or more before it is even ready to handle them. Might be wise to have a separate switch in the PV side of things to act like some kind of delay on the PV side.

Just something to consider before adopting a one breaker to bind them together and rule them all scenario.

bigrovar:
abeg if u love your life and property change that setup asap .. you are seriously playing with fire .. your setup is probably over a 1000 dollars don't lose it because of a 10 dollar protection unit. Contact guys here and pick a solid well sized DC breaker.

Here is why u should worry:
AC and DC are two different beast. As oga Frankie stated DC gives constant current that's why it is symbolised by a line and a dotted line. AC on the other hand alternate it's current from say 2 amps to 0amps to 2amps on and on and on it does this so fast like sometimes 50 times in a second (in that case 50z) .. now when designing breakers for AC application. The anti short circuit trip is designed to break the circuit when it drops to zero. Because of the alternating nature of AC.. when the current is dropping to zero any break in connection stops it in its track.. hence u can set the trip off curve is low.

For DC not the case DC current is constant. 20A DC is always 20A dc no BS no mago mago.. no awilo movement. DC breakers are designed to catch DC surge and the anti short circuit gap is much wider to prevent the current from jumping across re-bridging the contact. DC surge arc are not stopped by a break in the circuit (unlike AC breakers) hence DC circuit breakers are designed differently. They are designed to ensure a DC current surge is effectively stopped in its track.

Can an AC breakers trip when used in DC application yes. Can it be guaranteed to trip effectively especially when high current is involved. No it can trip but then the DC current can jump over the bridge and bridge the circuit.. you definitely don't want that.

Am sure my physics colleagues can explain this better.