BarracudaBob
Harvesting free photons from clean fusion
they are 4 poles but they loop them through both sides to increase the voltage. Many different types with same switch.
dc Circuit Breaker
- Thread starter davy
- Start date
Q-Dog
¯\_(ツ)_/¯
BarracudaBob
Harvesting free photons from clean fusion
they do it on the single pair. They loop it back so it goes through 4 contacts with two wires. Increases the voltage rating.
I thought it was a cool idea, all good
Q-Dog
¯\_(ツ)_/¯
The IMO is rated for 700 volts. I don't need to increase the rating.
Fuses and breakers on PV strings are useless for overcurrent protection. PV source circuits are inherently limited to 1.25 x Isc (the 1.25 acounts for edge of cloud enhancement) and the conductors should be sized for 1.56x Isc. So the fuses and breakers will never trip unless you have more than two strings in parallel.
Might as well just use a disconnect.
The Dihool and many other of the inexpensive discos aren't listed products so using them is an NEC violation. If you're getting inspected go with a listed one like IMO.
Might as well just use a disconnect.
The Dihool and many other of the inexpensive discos aren't listed products so using them is an NEC violation. If you're getting inspected go with a listed one like IMO.
Do DC isolation switches of this sort have or require arc quenching?
But be sure to read the reviews first.
OzSolar
Whatever you did, that's what you planned.
Interesting, I use those all time and have never had those problems but if someone takes the time to make a negative review there's a dozen more that didn't.
SunSurge
New Member
I spoke with SS regarding my solar panel strings for 36 panels to the Flexboss21. They said we could do 12,12 on mppt1 and 6,6 on mppt2 and recommended using two of the following disconnect. After looking at this later, I noticed this disconnect is rated for 32amps. My question is whether connecting each sting of 12 panels to the disconnect leave it in series or does it combine the amperage? If combined, the amperage would be 43.02 amps and exceed the rated amperage.
signaturesolar.com
IMO DC Disconnect Rooftop Isolator Switch | 4 Pole | 2 String
The IMO DC Disconnect Rooftop Isolator Switch ensures safe disconnection of rooftop solar systems, offering reliable operation and compliance with industry standards for enhanced system safety.
signaturesolar.com
pollenface
Solar Wizard
I'm buying Geya at the moment.
traumaboyy
New Member
Wow!! Using all circuit breakers now....Just ordered two of those...Thank you guys!!!
Brucey
Velcro Man
That disconnect supports a max of 32A. And two strings.I spoke with SS regarding my solar panel strings for 36 panels to the Flexboss21. They said we could do 12,12 on mppt1 and 6,6 on mppt2 and recommended using two of the following disconnect. After looking at this later, I noticed this disconnect is rated for 32amps. My question is whether connecting each sting of 12 panels to the disconnect leave it in series or does it combine the amperage? If combined, the amperage would be 43.02 amps and exceed the rated amperage.
IMO DC Disconnect Rooftop Isolator Switch | 4 Pole | 2 String
The IMO DC Disconnect Rooftop Isolator Switch ensures safe disconnection of rooftop solar systems, offering reliable operation and compliance with industry standards for enhanced system safety.
If you use two of the disconnects, disconnect 1 string 1 will be 12s (at Isc of 1x), string 2 will be 12s (at Isc of 1x).
Same concept for second disconnect for mppt 2 but with two 6s strings. So you should be well under the 32A limit.
Q-Dog
¯\_(ツ)_/¯
Each pole is rated for 32 amps.I spoke with SS regarding my solar panel strings for 36 panels to the Flexboss21. They said we could do 12,12 on mppt1 and 6,6 on mppt2 and recommended using two of the following disconnect. After looking at this later, I noticed this disconnect is rated for 32amps. My question is whether connecting each sting of 12 panels to the disconnect leave it in series or does it combine the amperage? If combined, the amperage would be 43.02 amps and exceed the rated amperage.
IMO DC Disconnect Rooftop Isolator Switch | 4 Pole | 2 String
The IMO DC Disconnect Rooftop Isolator Switch ensures safe disconnection of rooftop solar systems, offering reliable operation and compliance with industry standards for enhanced system safety.
SunSurge
New Member
Ok, sounds like it is 32A per pole as Q-Dog mentioned. Thanks.
SunSurge
New Member
Ok, 32A per pole which should work fine. Thanks.
ksmithaz1
Solar / EV Junkie
I like the Langir double pole non-polarized DC breakers. I would also put the spike protectors on it, just stuff it in a box. I can't think of a good reason not to just go ahead and use a breaker. The only problem I had was a bit of underprovisioning, my 2nd set of panels was tripping the 25A breaker in parallel, just right on the edge NMOT was 12+A with MAX at like 12.98, feeding a 25A MPPT. Each string is feeding a 15A, combined with DINKLE's to the now 32A that feeds up to the MPPT. This way I can shut off whatever I want.
Proper design per the NEC (and good practice) is to select OCPDs rated at least 25% higher than the maximum expected continuous current expected in the circuit
This is to avoid nuisance trips and applies to all circuits, not just PV.
Max continuous current in PV source circuits is considered to be 1.25 x Isc due to cloud reflection enhancement. So you end up with OCPCs sized for 1.56 x Isc. Conductors should of course be sized for the OCPDs selected.
If you aren't combining more than two PV source circuits then you can skip the OCPDs since the PV circuits are current limited and should never trip anyway. They don't enhance safety. You can just use the IMO isolators or equivalent. The isolators and conductors should still be sized for 1.56 x Isc (or 2 x 1.56 x Isc if you're combining 2 source circuits).
Re adding SPDs, if you want those place them at the MPPT end of the source circuits, not out in solar array. You need to protect your sensitive electronics, not the PV modules.
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