hwy17
Anti-Solar Enthusiast
I think we could still use detailed wiring pics. There's all sorts of possibilities and people jump to conclusions especially about grounding and bonding.
Live Ground Shocked 5 Year Old
- Thread starter Joshua787
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Auto transformer looks hard wired into 120v loads panel (right panel). Flipping its breaker (left panel) would remove both L1 and L2 so no chance of 120V loads being unbalanced.
Big question for @Joshua787 is the ground rod connected to Growatt's ground and is there a neutral to ground bond at the breaker panel? My guess is the neutral to ground bonding screw is in place inside Growatt and no N-G bond in the panel. This will bias the neutral to 120Vac in relation to earth ground. So L2 is actually at earth potential, N is at 120V and L1 is at 240V. This is probably why you were measuring live voltage in the outlet with breaker turned off. Your neutral to ground had 120V.
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Mike 134
Solar Enthusiast
Just a quick follow-up to my advice I offered. I fed my family working as an electrician giving me enough knowledge to know I can't walk you through this online and be 100% certain of your family's safety.
To those posting help do you feed your family doing electrical work? or is this a hobby? The OP has a right to know just how much you really know.
hwy17
Anti-Solar Enthusiast
DIY is the name of the forum. Everyone here is tacitly accepting the risk of their own actions and understanding the nature of the advice received.
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Hedges
I See Electromagnetic Fields!
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Nope.
But how many electricians understand inverters? Or the nuances of auto-transformers?
Besides, I'm "experienced".
I agree it is best to have someone who understands these things to check it over and debug in person.
For many of us here, that would be ourselves. Even better to get a second opinion.
But how many electricians understand inverters? Or the nuances of auto-transformers?
Besides, I'm "experienced".
I agree it is best to have someone who understands these things to check it over and debug in person.
For many of us here, that would be ourselves. Even better to get a second opinion.
Hedges
I See Electromagnetic Fields!
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"grounding" the container will not stop it from being a shock hazard. Bonding and grounding could.
That's why we keep telling people they need a wire that bonds PV panel frames to inverter chassis. Not just a separate ground rod at the frames.
The two most likely issues with OP's system are
1) PV frames have AC capacitively coupled to them because inverter imposes AC on PV+/-
2) Inverter has one of its two 240V legs bonded to chassis, and auto-transformer center tap ("Neutral") has a path to earth (i.e. is "grounded"). As Antron describes.
Adding a separate ground for the container could mean two ~ 25 ohm connections to earth, with current running through them.
Ideally we would get to see a schematic of entire system.
That's why we keep telling people they need a wire that bonds PV panel frames to inverter chassis. Not just a separate ground rod at the frames.
The two most likely issues with OP's system are
1) PV frames have AC capacitively coupled to them because inverter imposes AC on PV+/-
2) Inverter has one of its two 240V legs bonded to chassis, and auto-transformer center tap ("Neutral") has a path to earth (i.e. is "grounded"). As Antron describes.
Adding a separate ground for the container could mean two ~ 25 ohm connections to earth, with current running through them.
Ideally we would get to see a schematic of entire system.
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robbob2112
Doing more research, mosty harmless
First, this is DIY.
Second, it is pretty arrogant of you to assume nobody here knows anything about this sort of problem.
Many here have practical experience and more than enough education to know what they are saying. I know I wouldn't give advice in here until the OP posts back pictures and a wiring diagram so I wouldn't give a wrong answer.
I can see your point that the OP should carefully consider the advice he is given before doing things. And be double careful about testing before letting his famliy near. But it doesn't take a certified master electrician to track down an issue like this.
Partimewages
Solar Addict
34 year licensed electrician. Let me be the first one to say I don't know it all.
I know an abundance of trade people. Most electricians don't understand low voltage high current circuits.
WE CAN ALL LEARN FROM EACH OTHER!
I know an abundance of trade people. Most electricians don't understand low voltage high current circuits.
WE CAN ALL LEARN FROM EACH OTHER!
timselectric
If I can do it, you can do it.
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Short answer.
Your system is not properly grounded.
You don't have a N/G bond.
Your system is not properly grounded.
You don't have a N/G bond.
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timselectric
If I can do it, you can do it.
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These are not setup for North America .
Their N, your L2, is bonded to ground.
Modifications are required for North American use.
And I'm pretty sure he's got no NG bond at the breaker panel. Having NG bonding screw in Growatt and NG bond at the panel would cause a short circuit through the autotransformer and trip the inverter.
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finite
New Member
This is a very specific niche in the electrical industry, I attended a trade highschool in CT so ive been electrical work since i was a teenager, i am now 40 yrs old, lost a year here and there in 2008 and a year in the .MiL, but the rest is all high end homes, lighting control, generators, landscape lighting, service changes...lots and lots of service changes. But my solar knowledge pertaining to the inner workings and nuiances of each manufacturer make me low on this totem pole. General electrical practices will still spill over..
the side job electrician hed prolly find Wouldnt know what to do, and if he's the fake it till you make type would prolly smoke something in the process of poking around.
the side job electrician hed prolly find Wouldnt know what to do, and if he's the fake it till you make type would prolly smoke something in the process of poking around.
Hedges
I See Electromagnetic Fields!
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Only if chassis of Growatt does connect to chassis of auto-transformer.
I can't make out color of wires and connections well enough in photo with breaker panel.
Unfortunately, I'm experienced at mis-connecting chassis. Good to check between all boxes for volts, and for ohms.
Mike 134
Solar Enthusiast
Not in the least just look at the wide variety of answers thrown out there from the armchair DIYers. Every response should have first asked and received more information before making their wild a** guess based on what they think they know. It's called the Dunning-Kruger Effect.
End of rant
Does not have to. Please excuse my ugly drawing. Still need to figure out which wire was bonding to shipping container via 120v outlet or if there was earth ground connection to the Growatt. Need more info.
Dagoth Ur Does Solar
Solar Enthusiast
This entire thread is just making me glad I didn't opt to put my system in my metal shed. Harder to energize a locked up brick building than a shipping container...
Helpful people offering possible solutions based off the information someone provides isn't Dunning-Kruger lol.
timselectric
If I can do it, you can do it.
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Exactly
And instead of the breaker or inverter protection doing what it's supposed to.
Everything that should be grounded is live.
timselectric
If I can do it, you can do it.
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I don't need any pictures to know what the problem is.
But that's because I am familiar with their equipment.
And 40 years in the trade , doesn't hurt.
