Can you do a similar video of battery DC isolators/breakers? Seems to be hard to find a good value 60v 125a non-polarized one (ignoring risky Chinese options).
@@efixx But you don't ever want to actually turn the handle on those DC disconnects while it is carrying current anyway. Literally, you don't want to do it. Those disconnects should only be used in an emergency or when the current is known to be zero and that's it. The proper way to shutdown the charge controllers or inverters is to use the soft-off switch on the inverter or the bluetooth app to turn off the charge controllers. THEN you can turn the manual disconnects for added safety.
@@efixxIt isn't really about current flow is it? It's about not having any voltage down stream from the isolator which can cause electrocution The existing current flow isn't what causes electrocution of you when you touch a live part. It's the presence of the dangerously high voltage which then causes a separate current to pass through you, frying you. So the correct answer to the question, is that it removes any dangerously high voltages from the MC4 connectors.
I disagree about using a bare ferrule. Double-insulated 10 AWG solar cabling actually does (barely) fit under the ferrule's plastic guard, and having the guard significantly reduces wire play at critical junctions. If its close you can still make it fit by applying a heat gun to the plastic guard for a few seconds, I strongly recommend that the guard not be removed. Manual DC isolators should be banned, period. They have caused so many frigging fires its not even funny. They have no thermal trip, often not even spring-loaded, minimal arc extinguishment, minimal uses under load with no indication that replacement is necessary. They were originally designed as a cheap way to avoid putting a breaker in but obviously over the years that has proven to be disastrous. Australia is finally scrapping the nonsense about putting disconnect switches up on the roof. OMG that was such a disaster! The U.S. is settling on "rapid shutdown" devices on every 1 or every 2 panels (now integrated into the micro-inverter or optimizer). That way the "big red button" outside the house doesn't have to be current-carrying, and it can shutdown the entire solar system. The most you ever want to have on the roof is an inline fuse at the end of each string, and that's pretty much it. But even that isn't needed when there is a rapid-shutdown device and insulation monitoring. No more combiner boxes on the roof either... they should be at street level and easily acecssible. And no more manual DC isolators in their own little mini-enclosures exposed to the elements. What a disaster those have been. You demonstrated in your video very succinctly why its such a bad idea... if one is going to have a DC isolator on an outside wall somewhere, it should be mounted inside a larger enclosure and down at street level or inside the garage or something. NOT exposed to the elements, period. I far prefer using solar combiner boxes for this purpose even when there is only one string. They have the integrated fuse, sometimes backfeed diodes too, and a master-breaker on the back-haul. It means bringing the cables for the individual strings all the way back to street level, but it is so much easier to maintain. Then you just have a second master breaker for each backhaul cable at the equipment and you are done. And those breakers are just *unpolarized 2-pole 1000V DC breakers*. No messing around. Real breakers, really unpolarized, and none of this 200VDC or 300VDC or 600VDC nonsense. 1000VDC. Plus they have the advantage at that point in the back-haul of only having to deal with current one-way, so the installer can just follow the polarity labeling on the breaker (even unpolarized breakers tend to have polarity labeling so installations are uniform). That way there is no mistake and no worries about 2-way current. -Matt
What a wonderful explanation 👏🏼
Can you do a similar video of battery DC isolators/breakers? Seems to be hard to find a good value 60v 125a non-polarized one (ignoring risky Chinese options).
Good idea - on it !
And 2 pole
Sounds good.
What's the purpose of inverter dc isolators if they're still connected to the inverter?
Kills the feed from the panels to the inverter.
Stops the current flow so you can safely unplug MC4 connectors.
You never want to disconnect an on load mc4! Very bad idea!
@@efixx But you don't ever want to actually turn the handle on those DC disconnects while it is carrying current anyway. Literally, you don't want to do it. Those disconnects should only be used in an emergency or when the current is known to be zero and that's it.
The proper way to shutdown the charge controllers or inverters is to use the soft-off switch on the inverter or the bluetooth app to turn off the charge controllers. THEN you can turn the manual disconnects for added safety.
@@efixxIt isn't really about current flow is it? It's about not having any voltage down stream from the isolator which can cause electrocution
The existing current flow isn't what causes electrocution of you when you touch a live part. It's the presence of the dangerously high voltage which then causes a separate current to pass through you, frying you.
So the correct answer to the question, is that it removes any dangerously high voltages from the MC4 connectors.
I disagree about using a bare ferrule. Double-insulated 10 AWG solar cabling actually does (barely) fit under the ferrule's plastic guard, and having the guard significantly reduces wire play at critical junctions. If its close you can still make it fit by applying a heat gun to the plastic guard for a few seconds, I strongly recommend that the guard not be removed.
Manual DC isolators should be banned, period. They have caused so many frigging fires its not even funny. They have no thermal trip, often not even spring-loaded, minimal arc extinguishment, minimal uses under load with no indication that replacement is necessary. They were originally designed as a cheap way to avoid putting a breaker in but obviously over the years that has proven to be disastrous.
Australia is finally scrapping the nonsense about putting disconnect switches up on the roof. OMG that was such a disaster! The U.S. is settling on "rapid shutdown" devices on every 1 or every 2 panels (now integrated into the micro-inverter or optimizer). That way the "big red button" outside the house doesn't have to be current-carrying, and it can shutdown the entire solar system.
The most you ever want to have on the roof is an inline fuse at the end of each string, and that's pretty much it. But even that isn't needed when there is a rapid-shutdown device and insulation monitoring. No more combiner boxes on the roof either... they should be at street level and easily acecssible.
And no more manual DC isolators in their own little mini-enclosures exposed to the elements. What a disaster those have been. You demonstrated in your video very succinctly why its such a bad idea... if one is going to have a DC isolator on an outside wall somewhere, it should be mounted inside a larger enclosure and down at street level or inside the garage or something. NOT exposed to the elements, period.
I far prefer using solar combiner boxes for this purpose even when there is only one string. They have the integrated fuse, sometimes backfeed diodes too, and a master-breaker on the back-haul. It means bringing the cables for the individual strings all the way back to street level, but it is so much easier to maintain. Then you just have a second master breaker for each backhaul cable at the equipment and you are done.
And those breakers are just *unpolarized 2-pole 1000V DC breakers*. No messing around. Real breakers, really unpolarized, and none of this 200VDC or 300VDC or 600VDC nonsense. 1000VDC. Plus they have the advantage at that point in the back-haul of only having to deal with current one-way, so the installer can just follow the polarity labeling on the breaker (even unpolarized breakers tend to have polarity labeling so installations are uniform). That way there is no mistake and no worries about 2-way current.
-Matt