APSystems installation

[Pir8radio]

Well, it sounds like you have actually planned the system and if the inspector accepts it, you win.

I’m sorry If I came off as argumentative. I’m seriously looking for a hole in my logic. I wasn’t trying to argue or “win”.
inspector approved but that’s not saying much where I live. I want it to be safe regardless of what anyone said is good.

[Ampster]

Good point. I still suspect an inspector would be unhappy.

Yes, I agree. I don't even know why someone would add another point of failure in an outdoor environment like that.

[RShackleford]

It really comes down to what the AHJ determines what is allowed or not.

Yep. I asked my AHJ if I needed fence around my ground-mount system (which can have voltages of up to 600vdc in a string) and he said "no" and I asked what keeps someone from grabbing those wires and he said "common sense". I guess as far as NEC, 599v is no different than 240v, and maybe having un-covered 240vac Romex would be ok in such a situation ...

[RShackleford]

Yes, I agree. I don't even know why someone would add another point of failure in an outdoor environment like that.

Except, as @Pir8radio said, "what do you think a branch or bus cable is that they sell for micro inverters ?" IOW, there's gonna be connectors. Thing is, though I haven't yet seen one of the APSystems connectors in person, they don't appear as though they have bare-metal prongs.

[bob-n]

Right. There is no exposed metal, either on the male or female of the APsystems connector.

[NewBostonConst]

Pir8radio, I believe you stated you were cutting off the factory connector so you will likely be using a junction box. If you run 4 conductor cable and your plug is 4 conductor (Ground, Common, L1, L2)

So, if you place a dpdt relay in the box with a 120vac coil you can connect the relay coil between the common and L1, and then L1/L2 wires are connected to the NO relay contacts.

So when the plug is attached to power, the relay is energized and power flows to and from the micro inverter. Then when the plug is unplugged the neutral connection is lost, opening the relay and taking power off the other terminals of the plug. So rapid shutdown has its time to power down with no power on the plug connectors. So all is safe.

Hope this helps and makes your setup safer. This is how I did mine a while back, though I have not had the chance to unplugged under load and test for power. Mybad....

[SunEagle]

Generally, when someone plugs into an outlet, the outlet is on a shared circuit. If your outlets are individually wired back to a breaker rated for the wire gauge in use, that's safer, but you have taken a compliant Micro Inverter and downgraded it to a Plug-In inverter which, because they are often plugged in to branch circuits, is not permissible. I don't know the subtleties of the code regarding using a dedicated unique outlet & matching plug instead of a hardwire & disconnect.

Actually some AHJ will allow a plug on a dedicated Circuit breaker to back feed from solar. That usually means some type of non typical plug & receptacle that keeps a standard plug from being connected to the receptacle.

Having a quick "plug & play" system works if you can get the AHJ to understand it is safe and "fool proof" from being hacked by a non electrical educated person. Although having a hard wired terminal box for the pv input power seems to streamline the process.

[Pir8radio]

Except, as @Pir8radio said, "what do you think a branch or bus cable is that they sell for micro inverters ?" IOW, there's gonna be connectors. Thing is, though I haven't yet seen one of the APSystems connectors in person, they don't appear as though they have bare-metal prongs.

They do not have bare prongs you are correct, but like i said a selling point for the ap systems bus plugs is that those plugs ARE the AC DISCONNECT required by nec, thats why they shield the prongs on both ends, due to ac disconnect requirements in nec. I have ac disconnect breakers in sight of the inverter so nec is met, not worried about using my plugs as "AC Disconnects" for the solar part of nec.

[Pir8radio]

Pir8radio, I believe you stated you were cutting off the factory connector so you will likely be using a junction box. If you run 4 conductor cable and your plug is 4 conductor (Ground, Common, L1, L2)

So, if you place a dpdt relay in the box with a 120vac coil you can connect the relay coil between the common and L1, and then L1/L2 wires are connected to the NO relay contacts.

So when the plug is attached to power, the relay is energized and power flows to and from the micro inverter. Then when the plug is unplugged the neutral connection is lost, opening the relay and taking power off the other terminals of the plug. So rapid shutdown has its time to power down with no power on the plug connectors. So all is safe.

Hope this helps and makes your setup safer. This is how I did mine a while back, though I have not had the chance to unplugged under load and test for power. Mybad....

The inverter shutdown happens in 120ms adjustable down to 60ms which is almost as fast as a typical relay drop-out time anyway, also there is no neutral on the micro inverters, just split phase and ground.

[NewBostonConst]

The inverter shutdown happens in 120ms adjustable down to 60ms which is almost as fast as a typical relay drop-out time anyway, also there is no neutral on the micro inverters, just split phase and ground.

Per NEC 2014/2017 690.12 Rapid Shutdown can be up to 10 seconds or 30 seconds depending on the design.

I don't find any document that states the times you are quoting....If you are correct then I agree a relay is not needed.

[Ampster]

The NEC requirement is the maximum allowed. As a practical matter it probably depends on the individual device if it is less than that or not. If Pir8radio is referring to his inverter then that is where one would find that information.

[SunEagle]

The NEC requirement is the maximum allowed. As a practical matter it probably depends on the individual device if it is less than that or not. If Pir8radio is referring to his inverter then that is where one would find that information.

I agree that the actually time an inverter cuts out is based on its internal software programming. The NEC requirement is just the max allowed to protect first responders but not necessarily the time a system truly disconnects from the grid.

[derrickhoward]

I am on par with you. Just installed 22 340W Seraphim 72 cell panels with 5 QS1 and a YC600. Couldn't get anything to work. Bob, is your system running properly? Did your trunk cable have the center contact ground? The cable Renvu sent me had no center pin or ground wire. My "installer," (the certified guys that are going to sell my srecs for me), Had a lengthy chat with APSystems tech guy, after a week of trying to get through. He said that APSystems has never made a 2 conductor cable. It needs that center ground. Renvu told me they contacted AP and it should work fine with external ground wire connected. I don't know who to believe. I called Renvu, and they sent me the cable with 3 conductors with zero arguments, so I'm leaning toward APSystems. I've installed the new cable on half my system at dark last night. I havent been able to get on the APSystems EMA site since last year, so see if anything is different on the app when I get home...

[bob-n]

Derrick,

My system is running. I may have been excessive on grounding. I ran the three-wire cable including ground all of the way to the ground point (not neutral) at my main load center / circuit breaker panel. I also ran an external 6-gauge ground to the rails, which bonds to the panel frames and to the QS1 ground and also goes to the load center ground, so that's a parallel ground path.

This is just speculation, but I can envision a reason why the inverter requires ground. It may sense each phase to ground and won't turn on until each phase gets 120VAC. If you have no ground connection to the QS1 chassis or the QS1 cable, QS1 chassis might float to one leg or the other. To ensure safety, the QS1 may sense one phase below 110V and decide to stay off.

Have you tested:
1) That the panels put out DC?

Next, have you tested:
2) That each inverter is seeing 240VAC from the mains at it's inputs and 120VAC from mains phase to the star washer ground?..

Do you have a clamp-on ammeter to check current coming out of the inverters? That would be the next step. If you don't have one, they sell cheap ones with little-known brands for under $30 on amazon that are adequate and very handy. For example:

https://www.amazon.com/s?k=clamp-on+ammeter

[derrickhoward]

All 6 inverters are online. Rails and inverters are (chassis) grounded. Ran black, red, green back to disconnect and onto breaker panel.