Safe Grid Use of the 5000ES and transformer

[Samsonite801]

Did anyone here buy a couple of these 5k ES Growatts with the transformer solution, and having serious buyers remorse now and want to sell it to me for super cheap (just so I can have a fun toy to play with)...

You probably don't want to run the risk of putting anything you own or other people into harm's by way now, so maybe you'd rather just sell the stuff (in the name of science / research / forensic study)...

I promise I won't kill anyone with it...

Besides, someone's got to check that ground standoff and measure the gap, and see if it was removed properly.

 

[robby]

I would bet that 3/4 of all off grid inverters sold and used in North America are not UL listed. The electrons don't care if they are in Europe or Murica. Most electrical equipment is built in China for international markets. with the exact same components and acceptable voltage and frequency range for all markets. If Signature Solar did not do their homework how come they are the only company I have found selling these who identified the ground bond as an issue and worked with the manufacturer to resolve it? You can't have it both ways. If you acknowledge that there is a problem with buying and using the "European" version direct from China with the required NG bond screw installed, then you also have to give credit to SS for identifying and working with the manufacturer on a solution. Signature Solar is not the manufacturer. If it turns out that the "arc gap" to the standoff continues to be a safety risk, it can also be resolved with some redesign by Growatt.

You could bet but you would be completely wrong. The DIY market for solar sales is a small section of the market.
Most people hire an installer and get their systems Grid tied and certified. They can then get any Tax rebates and sell back credit.
Most off grid systems are also installed by professionals. The fact is that most people do not like to mess around with high voltage electricity.

Companies like Enphase, Sol-Ark, SMA, Outback, Schnieder are some of the brands that are pushed by most Installers and in most cases they won’t install uncertified equipment.

 

[Quattrohead]

PeteB sounds like a shrill for someone.
Look, it's a great unit with many good features and when Growatt design and build a 120V version of it, they will knock it out of the park.
But for now, the 240v unit is not made for the USA electrical system and the bodge's to make it work here are unsafe.
Yes it could work for years with no problem, but safety is just like...well actually is insurance for when/if something goes wrong.

In fact, here is a perfectly safe use for it, powering a stand alone 240v HVAC system from panels and batteries with no connection the the home AC.

 

[Quattrohead]

Who is going to show us the bonding screw removed and the circitry around the area ?
I bet no one who sell's it LOL

 

[Hedges]

In fact, here is a perfectly safe use for it, powering a stand alone 240v HVAC system from panels and batteries with no connection the the home AC.

Could be, so long as you have a 240V only HVAC system.
A 240V window air conditioner (3 prong plug) could be it.
My HVAC system was installed as a 120V gas furnace plus 240V AC compressor. Blower motors and transformer are 120V.

You could still make this work but would still need a transformer. Autotransformer OK, but instead of 120/240V with centertap grounded, it would be fed with 240V having one side grounded. Be sure to wire 120V circuit to furnace with "Neutral" tied to that grounded wire (not to centertap), because only one leg is switched.
You would want transfer switch(s) so both furnace and A/C compressor can be fed from utility as well.

 

[Quattrohead]

I was thinking about the typical southern install of a totally electric unit. They are straight 240v.

 

[HighTechLab]

Could be, so long as you have a 240V only HVAC system.
A 240V window air conditioner (3 prong plug) could be it.
My HVAC system was installed as a 120V gas furnace plus 240V AC compressor. Blower motors and transformer are 120V.

You could still make this work but would still need a transformer. Autotransformer OK, but instead of 120/240V with centertap grounded, it would be fed with 240V having one side grounded. Be sure to wire 120V circuit to furnace with "Neutral" tied to that grounded wire (not to centertap), because only one leg is switched.
You would want transfer switch(s) so both furnace and A/C compressor can be fed from utility as well.

a 240v L-N stinger leg? That's almost as bad as working on a 240v 3 phase high-leg delta. Everyone I know where I grew up that had a high-leg delta has blown up at least one thing or more accidently connecting to B phase@208v l-n

 

[svsagres]

a 240v L-N stinger leg? That's almost as bad as working on a 240v 3 phase high-leg delta. Everyone I know where I grew up that had a high-leg delta has blown up at least one thing or more accidently connecting to B phase@208v l-n

Been there, done that, got the T-Shirt. Remote site I work with that has their own private hydro-electric system used to be wired 240V delta with a wild leg. More than a few people didn't know why every third breaker in the 3 phase panels had been skipped, and learned the lesson the hard way.

When we undergrounded the electrical distribution system (2400V delta generators on the turbines), we took the opportunity to swap to 120/208 Wye. Biggest issue we ran into was that suddenly all the clothes dryers, and boilers weren't putting out enough heat, until we obtained new heating elements for 208V rather than 240.

 

[robby]

Who is going to show us the bonding screw removed and the circitry around the area ?
I bet no one who sell's it LOL

I am sure someone in China is modifying a board right now to ship out.
What I would like to see is a tear down of one that has already been sold. @Will Prowse or @HighTechLab are you guys willing to make a video.

 

[kjswiley]

The problem is no one knew these were not designed for U.S.

Signature Solar knew, they preemptively removed the screw before selling us the units.

 

[Solar Guy Richard]

Who is going to show us the bonding screw removed and the circitry around the area ?
I bet no one who sell's it LOL

I'll see if I can get a picture shortly.

 

[Solar Guy Richard]

I am sure someone in China is modifying a board right now to ship out.
What I would like to see is a tear down of one that has already been sold. @Will Prowse or @HighTechLab are you guys willing to make a video.

I'll see if I can get a picture.

 

[Fosse]

Maybe folks who have actually built a lot of these might know more than the armchairs.

Someone should shut you up. You are damaging your companies reputation with your rudeness and assumptions. My advice to your company is stop selling these in North America, apologize, get rid of you because all you are doing is beating a dead horse. You're not even close to as clever as you think you are. If this is your way of thinking and dealing with people maybe we should buy nothing from you for our own safety?

 

[Ozark Tinkering]

 

[JohnGalt1717]

So question for those of us that have these:

If I set this up so that the neutral/ground bonding screw was removed and isolated, and hooked it up without an auto-transformer to drive all of my 240V loads (that don't have neutral like welder, air compressor, hot water heater, geothermal etc.) there'd be no problem correct? It's only 120V that's the issue in that scenario right?

 

[Solar Guy Richard]

So question for those of us that have these:

If I set this up so that the neutral/ground bonding screw was removed and isolated, and hooked it up without an auto-transformer to drive all of my 240V loads (that don't have neutral like welder, air compressor, hot water heater, geothermal etc.) there'd be no problem correct? It's only 120V that's the issue in that scenario right?

We are not aware nor testing any issues with using this as a 240v inverter. Lots of tests happening currently in about 100 other different configurations as put forth on this forum.

 

[JohnGalt1717]

We are not aware nor testing any issues with using this as a 240v inverter. Lots of tests happening currently in about 100 other different configurations as put forth on this forum.

Well it would seem that used as a grid connected (for charging) environment you'd have the same issue as before would you not? NA power is 120/120 on L1 and L2 whereas EU is L1 and N with L1 being full 240V. Thus if you grid connected this for charging, and didn't disconnect the bonding, you'd have issues. So it's very important for the bonding screw to be removed and a spacer put in, which is important for anyone that doesn't have one of your units.

I fortunately have a separate meter for 240V stuff, so with 4 of these I can drive all of those loads and then just use a 120V inverter for the rest so this will work I would think.

But I would also think that the ground from the meter into your splitter panel with the bonding screw removed and then ground out to each inverter's ac in earth would be required? (and then the same earth to your loads would also be required so you didn't create a ground loop?)

In my case, I don't have a ground to the transformer. It's L1 + L2 + N and then separate grounding rods (2) driven at the meters and the meters themselves have that ground tapped to the case. So presumably I wouldn't be creating potential on the ground by doing so?

 

[Ozark Tinkering]

 

[copec]

I don't know if anybody else said this, but pretty much every inexpensive low-frequency inverter that produces split phase power (ie direct from China), suffers the same problems as using an EU inverter with the neutral<->ground bond removed. I have a Growatt 12000t low frequency inverter, and I've seen its internal auto-transformer balancing grid currents when in bypass mode (although the most I've ever seen was ~5A when there was a >3V difference between L1/L2 during the summer with all the neighborhood AC), the difference is that the auto-transformer L1/L2 breaker is the breaker to the inverter too.

Inverters that have contactors for L1/L2 on the auto-transformer for off-grid mode (should) have logic implemented to make sure that the auto-transformer is contacted before going to off-grid mode, so that there isn't a time, albeit milliseconds, where there isn't a neutral. That's why we can't just use a contactor with the dry contacts of an inverter to connect and disconnect an external or internal neutral of an auto-transformer - It doesn't have the specific logic to make sure the auto-transformer is contacted, and this will surely blow something up.

Most of my lot is a concrete pad with a Ufer ground, and I ran into this issue a few years ago when I installed my 12000t. I have a single neutral-ground bond in my main panel, separate neutral and ground connections to my subpanel (which actually now has every circuit of my home in it), and then L1/L2 go through the 12000t. If I disconnected neutral to the subpanel, then the currents would just go through the ground conductor, if I made a new ground by running a rod 50' away and running the conductor to the subpanel, so that I could disconnect that ground, then every neutral and ground in my house is now floating (well, with a relatively high resistance through earths), with the concrete pad and arbitrary metals bonded to the grid neutral/ground, which was just unacceptable. So I live with balancing grid currents sometimes.

 

[JohnGalt1717]

PS: The open question here is why there isn't a 5000US? The reason that @Will Prowse mentioned sort of is high voltage series strings of panels mainly. I can't find ANY split phase inverter + MPPT with even remotely comparable specs per MPPT and because all of my strings have to be unbalanced because of orientation of number I can have in a given orientation it's super important to get to 400+V. I can't just parallel and use higher amperage without major losses.

The only other units I can find are either 3 phase (even worse) or require 384VDC battery packs.

If @signaturesolarrichard and Growatt wanted to take the market by real storm they'd use this as an excuse to exchange people their current units with a US version that was split phase and auto-balancing (the math on the EE is straight forward to make this happen, you just have to parallel the fets to handle 100% load on a single leg if necessary, but the fets are really cheap, so it's pretty straight forward to do this. The hard part of the EE is the synchronization of parallel which is the other limiter in the market which is why people are doing this.

 

[Bud Martin]

I'll see if I can get a picture.

Please remove the PCB so we can see if the standoff is remved or not, or if they install insulator sheet between the standoff and the PCB or not.

 

[Bud Martin]

PS: The open question here is why there isn't a 5000US? The reason that @Will Prowse mentioned sort of is high voltage series strings of panels mainly. I can't find ANY split phase inverter + MPPT with even remotely comparable specs per MPPT and because all of my strings have to be unbalanced because of orientation of number I can have in a given orientation it's super important to get to 400+V. I can't just parallel and use higher amperage without major losses.

The only other units I can find are either 3 phase (even worse) or require 384VDC battery packs.

If @signaturesolarrichard and Growatt wanted to take the market by real storm they'd use this as an excuse to exchange people their current units with a US version that was split phase and auto-balancing (the math on the EE is straight forward to make this happen, you just have to parallel the fets to handle 100% load on a single leg if necessary, but the fets are really cheap, so it's pretty straight forward to do this. The hard part of the EE is the synchronization of parallel which is the other limiter in the market which is why people are doing this.

Last night I ask Growatt about the SPF-5000 ES vs SPF-5000 US:
They do not seem to understand about US wiring system regarding to Neutral and Ground, so I makes me wonder what they know and not know about the products.

Emails below:

刘庆存 (owen.liu@growatt.com)To:you + 2 more Details

Hi Bud Martin

Between L and N is 220V, there is no the Neutral ponit of split phase.

---

Owen Liu 刘庆存
Marketing Department

深圳古瑞瓦特新能源有限公司
ShenZhen Growatt New Energy Co.,Ltd.

Me:
Hi Owen,
So the SPF-5000 US is the US model so the Neutral is NOT connected to Ground not like the SPF-5000 ES that is supposedly has Neutral and Ground connected together, is that correct?

Best regards,
Bud Martin

刘庆存 (owen.liu@growatt.com)To:you + 2 more Details

Hi Bud,

SPF 5000 US is SPF 5000 ES US model, and its output 220V not the Split-phase.

---

Owen Liu 刘庆存
Marketing Department

深圳古瑞瓦特新能源有限公司
ShenZhen Growatt New Energy Co.,Ltd.

Me:
Hello,
Can you please tell me the difference between GroWatt SPF-5000 ES and SPF-5000 US?
I download the user manual for the SPF 5000 US but it shows as SPF-5000 ES user manual.
Do one of these two unit have 120/240VAC Split-phase output?
I am looking for 120/240V split-phase input and output for US electrical system.

Best regards,

Bud Martin

 

[JohnGalt1717]

Last night I ask Growatt about the SPF-5000 ES vs SPF-5000 US:
They do not seem to understand about US wiring system regarding to Neutral and Ground, so I makes me wonder what they know and not know about the products.

Emails below:

刘庆存 (owen.liu@growatt.com)To:you + 2 more Details

Hi Bud Martin

Between L and N is 220V, there is no the Neutral ponit of split phase.

---

Owen Liu 刘庆存
Marketing Department

深圳古瑞瓦特新能源有限公司
ShenZhen Growatt New Energy Co.,Ltd.

Me:
Hi Owen,
So the SPF-5000 US is the US model so the Neutral is NOT connected to Ground not like the SPF-5000 ES that is supposedly has Neutral and Ground connected together, is that correct?

Best regards,
Bud Martin

刘庆存 (owen.liu@growatt.com)To:you + 2 more Details

Hi Bud,

SPF 5000 US is SPF 5000 ES US model, and its output 220V not the Split-phase.

---

Owen Liu 刘庆存
Marketing Department

深圳古瑞瓦特新能源有限公司
ShenZhen Growatt New Energy Co.,Ltd.

Me:
Hello,
Can you please tell me the difference between GroWatt SPF-5000 ES and SPF-5000 US?
I download the user manual for the SPF 5000 US but it shows as SPF-5000 ES user manual.
Do one of these two unit have 120/240VAC Split-phase output?
I am looking for 120/240V split-phase input and output for US electrical system.

Best regards,

Bud Martin

The problem is that you're talking to marketing people and not engineers. It's more than time that Signature Solar and Growatt got in here with real EE people and owned this and answered real questions and were prepared to offer a fully UL listed product or refunded everyone their money because this entire thing is deceptive from both parties.

And honestly, the best way for Growatt et. al. to fix this, especially for those of us that are still awaiting delivery, is to allow us to exchange the ES for the US models with a straight exchange.

 

[robby]

Hi Bud,

SPF 5000 US is SPF 5000 ES US model, and its output 220V not the Split-phase.

---

I think its just as been discussed before, they leave off the ground screw and label it US model.
I don't think there is any other difference. I sure hope that if there is a Pad on the bottom of the PCB that they have some form of proper insulation between the pad and standoff. Even without a Pad it's not really safe to have that kind of small clearance without an insulator.

 

[Solar Guy Richard]

The problem is that you're talking to marketing people and not engineers. It's more than time that Signature Solar and Growatt got in here with real EE people and owned this and answered real questions and were prepared to offer a fully UL listed product or refunded everyone their money because this entire thing is deceptive from both parties.

And honestly, the best way for Growatt et. al. to fix this, especially for those of us that are still awaiting delivery, is to allow us to exchange the ES for the US models with a straight exchange.

We are here. We have built several complete systems, modified our shop, and numerous other steps to ensure a full diagnostic and testing of this issue so we can advise on a safe and operational system. We have been inundated with phone calls, emails, and website tickets about this and are doing our best to keep up with the volume in addition to working on a solution. We are being transparent in our research, replies, and response while we continue to research this. This has included ordering parts and literal construction as we do our best to replicate possibilities as outlined in user posts here. More to come, keep your eyes posted.