EG4 simple critical loads systems

[radiocq]

Hi, All. This is my first post. Go easy. I'm setting up a simple critical loads system in my house using the Reliance Controls Pro/Tran 2 Manual transfer switch (125 volts, 6 circuits). This transfer switch does not switch neutral but is popular for retrofits because it combines the transfer switch and critical load box.

My current plan is to use the EG4 3000EHV-48 inverter and connect it to a EG4-LL 48V server rack battery. I'll use a NEMA L5-30 cord to connect the AC output of the inverter to the transfer switch inlet. Simple. When grid is down, I can switch to the generator side of the transfer switch and energize my fridge, natural gas furnace, internet, etc.

However, I've been reading about the nonsense going on with EG4 and the Neutral/Ground bonding screw. My main panel is ground/neutral bonded (as it should be). Thus, since the transfer switch does not switch neutral, the inverter must NOT be ground/neutral bonded. However, based on the discussion in this thread, it's not clear if if that is supported by the 3000EHV-48.

How does this community recommend I proceed? I have the reliance transfer switch (model 306a1) already installed. I like the eg4 inverter and battery for its (seeming) safety, performance, and rock bottom price. However, if this nonsense continues, I don't think I want to get into this mess.

I was planning on slapping on a few solar panels in series that met the voltage requirement of the inverter and never charging from grid AC input. However, it would be nice to have the option (safely).

Should I proceed with this purchase before their sale ends? Are there other all-in-one inverters (~$700 like EG4 3k) that this community recommends?

Thanks, everyone. Looking forward to contributing my research and experience to the community.

 

[MisterSandals]

You should put "EG4" in your title to attract the EG4 experts.

 

[timselectric]

If you haven't purchased yet. The models being shipped now don't have the bonding screws. So, you should be good to go.
But
I would verify it with a continuity meter, just to be sure.

 

[radiocq]

If you haven't purchased yet. The models being shipped now don't have the bonding screws. So, you should be good to go.
But
I would verify it with a continuity meter, just to be sure.

I did read that. However, it's unclear if the common neutral is supported according to the other thread.

Also, I emailed signature solar and received a reply yesterday (1/27) from Timothy Huggins on whether the unit was NG bonded:

"Yes, the EG4 3k does have a neutral-ground bond. These units are UL certified to work with the bond in place by activating a bypass relay when a DC power source (solar or battery) is active."

This is directly conflicting with the other info I've seen.

 

[timselectric]

This is why I say to verify it yourself with a meter.
They should have regular meetings with all employees. So that they all give the same answers.

 

[Ampster]

I posted another thread about connecting the Reliance transfer switch for a generator input.

In your situation I would consider hard wiring the EG4 to the input of the transfer switch. the ground and neutral are separate and I would follow the advice of others regarding the configuration of the EG4. Presumably the EG4 would also be wired to the grid and the purpose of the transfer switch would be to give you some flexibility in terms of which loads are directly powered by the grid or which loads would be powered through the EG4. A more economical solution might be just a critical loads panel which would be a lot less than the Reliance switch. Sub panels with ten breaker slots are only $100 and breakers are $15 each which comes out to a lot less than the $300 for the Reliance switch. Isounds like you have already wired the transfer switch and the question is what to use for backup?

The biggest issue I found in planning that setup was which circuits to allocate? The priorities were the refrigerator, the freezer, water pressure, receptacles in the kitchen to be able to heat water and run a toaster oven and a receptacle in the bathroom for light and a space heater. The two bedrooms could be powered by extension cords from the bath receptacle and lights could also be run of those and the kitchen plugs.

 

[radiocq]

In your situation I would consider hard wiring the EG4 to the input of the transfer switch. the ground and neutral are separate...

Not a bad idea but wouldn't you like the flexibility of being able to plug and unlplug the inverter from the transfer switch? Especially since I'm already not sure about NG bonding? Is there a disadvantage to using the L5-30 inlet that came with the transfer switch?

Presumably the EG4 would also be wired to the grid and the purpose of the transfer switch would be to give you some flexibility in terms of which loads are directly powered by the grid or which loads would be powered through the EG4. A more economical solution might be just a critical loads panel which would be a lot less than the Reliance switch. Sub panels with ten breaker slots are only $100 and breakers are $15 each which comes out to a lot less than the $300 for the Reliance switch.

The main goal is 24 hours of backup for my fridge, furnace, lights, and internet if the grid goes down. The secondary goal is to shift a hungry load or two (dehumidifier) to permanent generator function in the spring and summer. Just power it off the PV input and make some money back on the system.

I didn't mention this in my main post, but I have an existing grid-tied roof-mounted system already running Enphase IQ7+ microinverters. They backfeed a double-pole breaker in my main panel and I'm using the reliance transfer switch for isolation from grid-tied solar. The last thing I want is the micros activating because they sense a potential difference. I looked into the Enphase 10 kWh AC coupled battery but it was $14k installed. Meh. I can backup my house critical loads for a lot less.

Isounds like you have already wired the transfer switch and the question is what to use for backup?

The biggest issue I found in planning that setup was which circuits to allocate? The priorities were the refrigerator, the freezer, water pressure, receptacles in the kitchen to be able to heat water and run a toaster oven and a receptacle in the bathroom for light and a space heater. The two bedrooms could be powered by extension cords from the bath receptacle and lights could also be run of those and the kitchen plugs.

Not quite the question but I like your advice. I know what circuits to back up. The question is should I got with the EG4 3k or shift gears and go with a Growatt, Victron, or something else since there is a lack of documentation from Signature Solar on the neutral-ground bonding. There's also a lack of clear answers from Signature Solar if the inverter safely supports the common neutral type transfer switches like the reliance.

 

[Ampster]

Not a bad idea but wouldn't you like the flexibility of being able to plug and unlplug the inverter from the transfer switch? Especially since I'm already not sure about NG bonding? Is there a disadvantage to using the L5-30 inlet that came with the transfer switch?

If your transfer switch already has the receptacle then a few bucks for the plug is worth the flexibility.

........
I didn't mention this in my main post, but I have an existing grid-tied roof-mounted system already running Enphase IQ7+ microinverters. They backfeed a double-pole breaker in my main panel and I'm using the reliance transfer switch for isolation from grid-tied solar. The last thing I want is the micros activating because they sense a potential difference. I looked into enphase 10 kWh AC coupled battery but it was $14k installed. Meh. I can backup my house critical loads for a lot less.

Are you going to be able to leverage that AC micro system when the grid is down?

Not quite the question but I like your advice. I know what circuits to back up. The question is should I got with the EG4 3k or shift gears and go with a Growatt, Victron, or something else since there is a lack of documentation from Signature Solar on the neutral-ground bonding. There's also a lack of clear answers from Signature Solar if the inverter safely supports the common neutral type transfer switches like the reliance.

That is a question that I can't answer. I see recent posts that the issue has been resolved and the EG4 is less money than at least the Victron. I have a future project for my older sister that will involve choosing between the Growatt or the EG4 so I will be following this.

 

[timselectric]

Whether they come right out and say it or not. They do support the common neutral system. Or they wouldn't be selling it with their name on it.
In SUB mode, this AIO makes a common connection between their inverter and grid neutral.
Maybe they haven't realized that, yet.

 

[radiocq]

Whether they come right out and say it or not. They do support the common neutral system. Or they wouldn't be selling it with their name on it.
In SUB mode, this AIO makes a common connection between their inverter and grid neutral.
Maybe they haven't realized that, yet.

Can you elaborate on this? What is SUB mode?

 

[radiocq]

Are you going to be able to leverage that AC micro system when the grid is down?

My plan is to currently keep the IQ7+ micros completely separate. However, I'm interested in your take on using them safely and cheaply. I was just going to set up ground mount PV in series that meets the minimum voltage requirement of the EG4.

 

[Adam De Lay]

Can you elaborate on this? What is SUB mode?

SUB is grid-bypass mode. Grid power flows through the inverter and powers the loads instead of battery power. Since there’s no bonding screw in the inverter anymore, there’s no dynamic bonding which would happen automatically when in battery mode. Your then relying on the bonding from the main service panel.

 

[Ampster]

My plan is to currently keep the IQ7+ micros completely separate. However, I'm interested in your take on using them safely and cheaply.hy

I have been using AC coupling for years to leverage my GT solar to compliment my hybrid inverters. Part of my evolution has been a result of the changing ecoonomics of Net Energy Metering in California. Now I am evolving toware more self consumption of my solar production. Your mileage may be different in Michigan. I also charge two EVs and try to do it from solar because my cost of kWhs produced by my solar is even less than my EV overnight rate. It all depends on where you are standing.

 

[timselectric]

Can you elaborate on this? What is SUB mode?

SUB mode blends the grid with the solar through the inverter.

 

[Adam De Lay]

SUB mode blends the grid with the solar through the inverter.

Kinda. It doesn’t really use the solar to power the loads like it should. SS told me that in SUB mode the inverter looks for the most “consistent source of power” to handle loads. So regardless of how much Solar you have coming in, it won’t cover your loads. You’ll end up seeing most of it going into your battery while the grid powers your loads.

I guess I should add though that my experiences are based on the 6500s. Maybe the 3000s work like they’re supposed to…

 

[radiocq]

SUB is grid-bypass mode. Grid power flows through the inverter and powers the loads instead of battery power. Since there’s no bonding screw in the inverter anymore, there’s no dynamic bonding which would happen automatically when in battery mode. Your then relying on the bonding from the main service panel.

SUB mode blends the grid with the solar through the inverter.

Thanks guys, and hello fellow ham. This seems like its good news for my use case since my main goal is emergency power but it would be nice to run critical loads from PV and get some payback on the battery. I could do it full time and if the battery gets too low I could set it to automatically switch to grid at a certain percentage.

However, reliance controls specifically warned me against simultaneously using AC input while also connected to the transfer switch. They said this would cause ground current. Even Nature's Generator transfer switch has a similar warning in bold: Do not charge Nature's Generator Elite by wall through AC input port when using Power Transfer Kit Elite.

So how does one use a common neutral transfer switch like reliance controls while simultaneously keeping the AC input of the inverter plugged into grid? It seems like you don't and have two safe alternative options...

1. Never connect the EG4 inverter to AC input while its connected to the transfer switch. Always charge from PV or other off-grid source.
2. Unplug inverter from transfer switch. THEN its safe to use grid AC input on inverter.

 

[timselectric]

Deleted post

 

[timselectric]

Kinda. It doesn’t really use the solar to power the loads like it should. SS told me that in SUB mode the inverter looks for the most “consistent source of power” to handle loads. So regardless of how much Solar you have coming in, it won’t cover your loads. You’ll end up seeing most of it going into your battery while the grid powers your loads.

Well, that's some kind of glitch.
Other Voltronic units work as they should.

 

[Adam De Lay]

Thanks guys, and hello fellow ham. This seems like its good news for my use case since my main goal is emergency power but it would be nice to run critical loads from PV and get some payback on the battery. I could do it full time and if the battery gets too low I could set it to automatically switch to grid at a certain percentage.

However, reliance controls specifically warned me against simultaneously using AC input while also connected to the transfer switch. They said this would cause ground current. Even Nature's Generator transfer switch has a similar warning in bold: Do not charge Nature's Generator Elite by wall through AC input port when using Power Transfer Kit Elite.

So how does one use a common neutral transfer switch like reliance controls while simultaneously keeping the AC input of the inverter plugged into grid? It seems like you don't and have two safe alternative options...

1. Never connect the EG4 inverter to AC input while its connected to the transfer switch. Always charge from PV or other off-grid source.
2. Unplug inverter from transfer switch. THEN its safe to use grid AC input on inverter.

Unfortunately I don’t have first hand experience with transfer switches so at the moment I’m not gonna be able to me of much help with these questions. Sorry

 

[timselectric]

Thanks guys, and hello fellow ham. This seems like its good news for my use case since my main goal is emergency power but it would be nice to run critical loads from PV and get some payback on the battery. I could do it full time and if the battery gets too low I could set it to automatically switch to grid at a certain percentage.

However, reliance controls specifically warned me against simultaneously using AC input while also connected to the transfer switch. They said this would cause ground current. Even Nature's Generator transfer switch has a similar warning in bold: Do not charge Nature's Generator Elite by wall through AC input port when using Power Transfer Kit Elite.

So how does one use a common neutral transfer switch like reliance controls while simultaneously keeping the AC input of the inverter plugged into grid? It seems like you don't and have two safe alternative options...

1. Never connect the EG4 inverter to AC input while its connected to the transfer switch. Always charge from PV or other off-grid source.
2. Unplug inverter from transfer switch. THEN its safe to use grid AC input on inverter.

The manufacturers are correct. Having both connected creates a neutral loop and a ground loop.