230V single phase 50hz UK, British virgin islands, few Caribbean islands use these voltage. 1 leg( L1) 230v and N is the Neutral. So you are right it is modified for US market.
In South Africa with a 240V grid supply system the Neutral and Earth is connected and grounded at the Utility, strictly speaking earth and Neutral are not allowed to be connected at the consumer side. You assumption is correct about the L N E markings on the inverter. However as electricians we often find our client's complain about voltage problems when getting power from the inverter, we thus mostly find a floating voltage between Neutral and Earth with elevated voltages of about 90V between N and earth. To date their seems to be no guidelines as what to do with the inverter E N to prevent elevated N E voltages.
Thanks for your videos! Your installation has been a great example to me! Thoughts: Although the isolation transformer really only does minimal isolation from voltage spikes (and wasn’t the purpose for using one), it got me thinking that I need to get a high quality surge protector for my panel that feeds the grid side of my inverters, for more resiliency. It wouldn’t be great if something took the grid out also took out the inverters. If in the future you want some large reasonably priced inverters for something else, or the growatts don’t work out, lookup Sandi Electric. I know a couple of people using their 30kw models. Also, they have higher battery voltage and higher string voltage charge controllers if you want, so you can save on wire.
Thanks! If these Growatts don’t workout I’m not going to be happy! Right now at this moment they are running my entire house including two central HVAC systems and 2hp pool pump. But I’ll keep what you suggested in mind. I have three Siemens SF140 TVSS installed on my electrical system. I will also be installing Midnight solar SPDs on my PV output circuits. You may want to check out Dr Arthur Bradley’s CZcams channel. He has some great EMP/Surge Suppression info there.
Jeff, I was thinking about this and wondered if the use of the isolation transformer would solve the issue of the high frequency inverters with respect to handing A/C and well motor startups. I see you added soft starts to your A/C but am hopeful that was for the generator and not the solar. In case it is unclear, I was thinking about low frequency inverters not having the motor startup issues because they have a transformer. The long and short is I am wondering if you have found the best of both worlds?
I added the soft starts because of my generator and also because I wanted to reduce inrush on the inverters. The bank of 5 - Growatt SPF500ES inverters have no difficulty with starting my 5 ton HVAC unit.
Is the grid neutral bonded to the transformer output neutral? If so, does that mean that there are two neutral-ground bonds? One in the first grid utility panel on the exterior and one in the transformer output panel? I ask because I thought it was standard (code) to bond the neutrals together. I’m going to guess not. I meant to mention in another of your videos that those Chtaixi 125A DC breakers are polarized, and can burn up if they flip when current is going the wrong direction.
The neutral derived from the isolation transformer must be bonded to the system ground. I do that in my system output panel on the load side of the transformer. I hadn’t considered what you mentioned about the breakers. May be modifying my wiring a bit.
@@captainobvious9188 the grid neutral is bonded to the ground at the first grid panel. The derived neutral is bonded to tge same ground at the panel on the load side of the transformer. There is no other connection other than the being bonded to the same ground.
Yes. It is big. I used it primarily for 2 reasons. My main protective devices are all 200A. Using a smaller transformer would require replacing either the primary or secondary breakers with smaller ones. Common transformer sizes include 10, 15, 25, 37.5, and 50kva. The heat strips in my 5 ton HVAC unit total 20kw. While it is very uncommon for both to be on at the same time it has occurred. That left me with picking a 37.5 or 50kva transformer. There wasn’t a $100 different between the two. In fact replacing tge 200A breaker with a 150A breaker would have cost more. There are some significant losses when using the transformer. I don’t remember exactly but it was significant. If you’ll look at some of my newest videos you’ll see I replaced all the Growatt units with two split phase Sol-Ark units. This eliminated the need for the transformer and it was removed from the circuit. You can also look at the thermal scan video I shared and see the heat inside the transformer.
@@jeffmotes2129 Just curious which isolation transformer you used. I am definitely using your system as a template (albeit different inverters), but would be nice to get the same one so wiring it is a lot easier.
Hey Jeff, love your videos, especially the one about following Dr Bradley's EMP writings. Got a question for you because this is the closest video I could find to my issue. I have a Growatt 3kw hybrid that is 120 only and the output voltage always stays consistent at around 120, but I'm getting pulsing lights all the time. They are good LEDs, but no matter what they pulse regardless of the size of the load on the inverter, and when I run something like the washing machine they pulse in rhythm with how the motor is running. Would this be where an isolation transformer would help smooth out the dirty power from the inverter? I already tried a Schaffner EMI filter with no help, but they are tuned to filter from 10KHz to 2MHz. So maybe the noise is at a lower frequency? If you have any input it would be much appreciated.
Hey Sam. I’ve heard of some inverters having these issues. Not sure how to resolve it. An isolation transformer may smooth the output some, but I’m not sure it would eliminate it.
I'm in the Philippines. Households are serviced with 2s wire from the transformer and when I look at a transformer on the poles, all have a ground wire going to the base of pole. Typical service here is just 100AMP, because even though the Philippines is very hot only 5% of households at the most have AC. Power is just too expensive for even upper middle class families to run AC. Big buildings here have 3 phase that supply 230v, 120v and 208v - the building owners own the transformers not the utility.
Jeff, Would appreciate it if you could make a video on your background. You seem to know a lot and I would like to know the certainty of your solution translating for everyone else. To me the Growatt has the biggest upside but I am looking for a 100% this solves it case closed. I think you have but I just don't know enough about electricity to say for sure. Second, would like to know why you chose Growatt. My guess is it was not due to low cost.
I may do that at some time. Not much on talking about myself though. I’ve been working in the electrical field for over 45 years, have a Master Electrician License, a Professional Engineer License, and have run a successful electrical contracting business since 1994.
@@jeffmotes2129 Jeff, you can be a youtube star if you want because you actually know what you're talking about while there are so many making videos who do not. What I encourage you to do and it is selfish I admit is talk more and explain the why's and don't be afraid of the camera. like explain why the auto transformers don't work and the isolation transformer does. Ian of watts247 made a few videos so we kinda got that but you're perspective might add some. How you sized the isolation transformer (I assume 100% load being 120v. I know you overbought but put that aside).Now we may not understand it all but I believe all information is good. Just basically everything you had to think through to make the decisions you made down to brands of breakers, wire chases etc. And links or descriptions please of the parts (thank you for showing part number of transformer in a video). And thank you for explaining why your breakers were all on one side.
A few questions. I'm not sure if it makes a difference in the following two scenarios if you have grid connection or off grid ..if there's a major difference in on or off grid for the following two potential failures please describe what would most likely happen. 1. If you're using a auto transformer like a lot of youtubers are and the auto transformer fails and the neutral is lost what exactly happens to the system and connected equipment? Some users are putting them on breakers but regardless...if the auto transformer shorts out or the breakers trip you loose the neutral. 2. What happens if the isolation transformer you're using fails either one or both sides and the neutral is lost? Does the tv and fridge blow up? Do the inverters get smoked? Additionally, what exactly is the appeal of this sort of setup when you can purchase cheap unites like the mpp / growatt or expensive ones like the conext and outback that already have 120/240 output at the inverter ..so you'd just have to parallel them and connected to the load panel? I'm curious why people are doing this when it's not much more for a unit that's already setup for split phase? Would it be better to have two isolation or auto transformers encase one gets taken out for whatever reason? Would this pass inspection for code or would they say those are not for the US and using a transformer isn't allowed per UL or other codes? And, thanks for taking the time to make these videos and educate us trying to learn ..it helps keep us safe and make good decisions. Your time is valuable and thanks for sharing it. I hope you continue to explain this step by step like you have and perhaps maybe even present a diagram once done for others to use as a template.
Hey Neal. If you lose your neutral whether it be from the grid, generator, inverter, isolation transformer, or autotransformer the results are similar. With the lost neutral the 120v devices will split the voltage between L1 and L2 based on impedance of the loads. Since the loads are not balanced some 120v circuits will get voltages less than 120v while others get voltages greater than 120v. Both cases are bad for your devices. I worked as a utility system engineer for a number of years at our local power company. Though it was extremely rare we did have occasions where we lost grid neutral serving a customer. This was always due to broken conductors or bad connections. We bought TVs and other appliances. Computers were rare back then. In a generator circuit or grid or isolation transformer when your transformer is switch off you simply lose power. The way many are using autotransformers on CZcams the autotransformer can easily be turned of or tripped with the inverter still maintaining an output. This creates that scenario I discussed above. The only way to use an autotransformer safely for your equipment is to tie one to each inverter output so that the autotransformer cannot be turned off without turning off the inverter output. If you have a large system this could easily cost as much as an isolation transformer large enough for the whole system. BUT if your inverters have a grid bypass mode autotransformers should definitely be avoided as I mentioned in the video.
Answer 2 - I was on a job site today where an isolation transformer faulted due to lightning. The breaker feeding the transformer tripped and removed power from it and it’s load. Though I think the lightning strike probably damaged a lot of equipment on the load side as well.
The reason I chose to use the Growatt SPF5000ES is because of its ability to stack units for 25kw output. That is my minimum requirement. I did not find any other inverters at the time (Nov 2021) that had that ability.
In my opinion one large isolation transformer is best for homes. It’s best to keep one neutral in your home and not multiple neutrals. If we’re to consider using autotransformer (for system with no grid pass through only) I would use one for each inverter installed and tie it to the same breaker being used for the inverter output.
Very informative!!! Liked the walkthrough and explanation. Made it easier to visualize and get it.
Thanks and you’re welcome.
230V single phase 50hz UK, British virgin islands, few Caribbean islands use these voltage. 1 leg( L1) 230v and N is the Neutral. So you are right it is modified for US market.
In South Africa with a 240V grid supply system the Neutral and Earth is connected and grounded at the Utility, strictly speaking earth and Neutral are not allowed to be connected at the consumer side.
You assumption is correct about the L N E markings on the inverter.
However as electricians we often find our client's complain about voltage problems when getting power from the inverter, we thus mostly find a floating voltage between Neutral and Earth with elevated voltages of about 90V between N and earth. To date their seems to be no guidelines as what to do with the inverter E N to prevent elevated N E voltages.
well said well done
you may save a life my freind thanks
Thanks for your videos! Your installation has been a great example to me!
Thoughts: Although the isolation transformer really only does minimal isolation from voltage spikes (and wasn’t the purpose for using one), it got me thinking that I need to get a high quality surge protector for my panel that feeds the grid side of my inverters, for more resiliency. It wouldn’t be great if something took the grid out also took out the inverters.
If in the future you want some large reasonably priced inverters for something else, or the growatts don’t work out, lookup Sandi Electric. I know a couple of people using their 30kw models. Also, they have higher battery voltage and higher string voltage charge controllers if you want, so you can save on wire.
Thanks! If these Growatts don’t workout I’m not going to be happy! Right now at this moment they are running my entire house including two central HVAC systems and 2hp pool pump.
But I’ll keep what you suggested in mind.
I have three Siemens SF140 TVSS installed on my electrical system. I will also be installing Midnight solar SPDs on my PV output circuits.
You may want to check out Dr Arthur Bradley’s CZcams channel. He has some great EMP/Surge Suppression info there.
Jeff, I was thinking about this and wondered if the use of the isolation transformer would solve the issue of the high frequency inverters with respect to handing A/C and well motor startups. I see you added soft starts to your A/C but am hopeful that was for the generator and not the solar. In case it is unclear, I was thinking about low frequency inverters not having the motor startup issues because they have a transformer. The long and short is I am wondering if you have found the best of both worlds?
I added the soft starts because of my generator and also because I wanted to reduce inrush on the inverters.
The bank of 5 - Growatt SPF500ES inverters have no difficulty with starting my 5 ton HVAC unit.
Thank you, Jeff…..can you suggest a source for the isolation transformers? Economical!
I’m an electrical contractor and bought mine through my Stuart Irby. You can find them used on eBay.
Is the grid neutral bonded to the transformer output neutral? If so, does that mean that there are two neutral-ground bonds? One in the first grid utility panel on the exterior and one in the transformer output panel? I ask because I thought it was standard (code) to bond the neutrals together. I’m going to guess not.
I meant to mention in another of your videos that those Chtaixi 125A DC breakers are polarized, and can burn up if they flip when current is going the wrong direction.
The neutral derived from the isolation transformer must be bonded to the system ground. I do that in my system output panel on the load side of the transformer.
I hadn’t considered what you mentioned about the breakers. May be modifying my wiring a bit.
I have some crimp ferrules coming for my battery wires. I’ll change them around when I crimp them ferrules on. Thanks for catching that for me.
@@jeffmotes2129 Is it bonded to the grid neutral too though? That’s really my question.
@@captainobvious9188 the grid neutral is bonded to the ground at the first grid panel. The derived neutral is bonded to tge same ground at the panel on the load side of the transformer. There is no other connection other than the being bonded to the same ground.
Jeff, just curious as to the losses associated with your transformer? 50KW is big for most households.
Yes. It is big. I used it primarily for 2 reasons. My main protective devices are all 200A. Using a smaller transformer would require replacing either the primary or secondary breakers with smaller ones.
Common transformer sizes include 10, 15, 25, 37.5, and 50kva. The heat strips in my 5 ton HVAC unit total 20kw. While it is very uncommon for both to be on at the same time it has occurred. That left me with picking a 37.5 or 50kva transformer. There wasn’t a $100 different between the two. In fact replacing tge 200A breaker with a 150A breaker would have cost more.
There are some significant losses when using the transformer. I don’t remember exactly but it was significant.
If you’ll look at some of my newest videos you’ll see I replaced all the Growatt units with two split phase Sol-Ark units. This eliminated the need for the transformer and it was removed from the circuit.
You can also look at the thermal scan video I shared and see the heat inside the transformer.
@@jeffmotes2129 Just curious which isolation transformer you used. I am definitely using your system as a template (albeit different inverters), but would be nice to get the same one so wiring it is a lot easier.
@@silverice9 I’ll get you a cat number.
@@silverice9 Hammond Power Solutions Sentinel G cat# SG3N0050LE 50kva transformer
@@jeffmotes2129 Awesome. You have no idea how much this helped me.
Hey Jeff, love your videos, especially the one about following Dr Bradley's EMP writings. Got a question for you because this is the closest video I could find to my issue.
I have a Growatt 3kw hybrid that is 120 only and the output voltage always stays consistent at around 120, but I'm getting pulsing lights all the time. They are good LEDs, but no matter what they pulse regardless of the size of the load on the inverter, and when I run something like the washing machine they pulse in rhythm with how the motor is running.
Would this be where an isolation transformer would help smooth out the dirty power from the inverter? I already tried a Schaffner EMI filter with no help, but they are tuned to filter from 10KHz to 2MHz. So maybe the noise is at a lower frequency?
If you have any input it would be much appreciated.
Hey Sam. I’ve heard of some inverters having these issues. Not sure how to resolve it. An isolation transformer may smooth the output some, but I’m not sure it would eliminate it.
Alright well thanks for the reply. If I ever figure it out I'll post back here@@jeffmotes2129
@@samgillis6224 please do. I’ve heard of others having this issue.
@@samgillis6224 since I installed the sol-arks I no longer use the transformer.
@@samgillis6224 check out Adam de Lay’s channel. He had some flickering issues. Not sure how he fixed it.
I'm in the Philippines. Households are serviced with 2s wire from the transformer and when I look at a transformer on the poles, all have a ground wire going to the base of pole. Typical service here is just 100AMP, because even though the Philippines is very hot only 5% of households at the most have AC. Power is just too expensive for even upper middle class families to run AC. Big buildings here have 3 phase that supply 230v, 120v and 208v - the building owners own the transformers not the utility.
Jeff, Would appreciate it if you could make a video on your background. You seem to know a lot and I would like to know the certainty of your solution translating for everyone else. To me the Growatt has the biggest upside but I am looking for a 100% this solves it case closed. I think you have but I just don't know enough about electricity to say for sure.
Second, would like to know why you chose Growatt. My guess is it was not due to low cost.
I may do that at some time. Not much on talking about myself though. I’ve been working in the electrical field for over 45 years, have a Master Electrician License, a Professional Engineer License, and have run a successful electrical contracting business since 1994.
@@jeffmotes2129 Jeff, you can be a youtube star if you want because you actually know what you're talking about while there are so many making videos who do not. What I encourage you to do and it is selfish I admit is talk more and explain the why's and don't be afraid of the camera. like explain why the auto transformers don't work and the isolation transformer does. Ian of watts247 made a few videos so we kinda got that but you're perspective might add some. How you sized the isolation transformer (I assume 100% load being 120v. I know you overbought but put that aside).Now we may not understand it all but I believe all information is good. Just basically everything you had to think through to make the decisions you made down to brands of breakers, wire chases etc. And links or descriptions please of the parts (thank you for showing part number of transformer in a video). And thank you for explaining why your breakers were all on one side.
A few questions. I'm not sure if it makes a difference in the following two scenarios if you have grid connection or off grid ..if there's a major difference in on or off grid for the following two potential failures please describe what would most likely happen.
1. If you're using a auto transformer like a lot of youtubers are and the auto transformer fails and the neutral is lost what exactly happens to the system and connected equipment? Some users are putting them on breakers but regardless...if the auto transformer shorts out or the breakers trip you loose the neutral.
2. What happens if the isolation transformer you're using fails either one or both sides and the neutral is lost? Does the tv and fridge blow up? Do the inverters get smoked?
Additionally, what exactly is the appeal of this sort of setup when you can purchase cheap unites like the mpp / growatt or expensive ones like the conext and outback that already have 120/240 output at the inverter ..so you'd just have to parallel them and connected to the load panel? I'm curious why people are doing this when it's not much more for a unit that's already setup for split phase?
Would it be better to have two isolation or auto transformers encase one gets taken out for whatever reason?
Would this pass inspection for code or would they say those are not for the US and using a transformer isn't allowed per UL or other codes?
And, thanks for taking the time to make these videos and educate us trying to learn ..it helps keep us safe and make good decisions. Your time is valuable and thanks for sharing it. I hope you continue to explain this step by step like you have and perhaps maybe even present a diagram once done for others to use as a template.
Hey Neal. If you lose your neutral whether it be from the grid, generator, inverter, isolation transformer, or autotransformer the results are similar. With the lost neutral the 120v devices will split the voltage between L1 and L2 based on impedance of the loads. Since the loads are not balanced some 120v circuits will get voltages less than 120v while others get voltages greater than 120v. Both cases are bad for your devices.
I worked as a utility system engineer for a number of years at our local power company. Though it was extremely rare we did have occasions where we lost grid neutral serving a customer. This was always due to broken conductors or bad connections. We bought TVs and other appliances. Computers were rare back then.
In a generator circuit or grid or isolation transformer when your transformer is switch off you simply lose power. The way many are using autotransformers on CZcams the autotransformer can easily be turned of or tripped with the inverter still maintaining an output. This creates that scenario I discussed above.
The only way to use an autotransformer safely for your equipment is to tie one to each inverter output so that the autotransformer cannot be turned off without turning off the inverter output. If you have a large system this could easily cost as much as an isolation transformer large enough for the whole system.
BUT if your inverters have a grid bypass mode autotransformers should definitely be avoided as I mentioned in the video.
Answer 2 - I was on a job site today where an isolation transformer faulted due to lightning. The breaker feeding the transformer tripped and removed power from it and it’s load. Though I think the lightning strike probably damaged a lot of equipment on the load side as well.
The reason I chose to use the Growatt SPF5000ES is because of its ability to stack units for 25kw output. That is my minimum requirement. I did not find any other inverters at the time (Nov 2021) that had that ability.
In my opinion one large isolation transformer is best for homes. It’s best to keep one neutral in your home and not multiple neutrals.
If we’re to consider using autotransformer (for system with no grid pass through only) I would use one for each inverter installed and tie it to the same breaker being used for the inverter output.
No idea on the inspection. Thankfully, where I live we don’t have to go through that hassle.
Its amazing, monstrous transformer.... That provides energy for a big company. 😅
A home with a 200 Amp Main Panel requires a 50 kva isolation transformer.