Live Ground Shocked 5 Year Old

[Joshua787]

Hi All,

I have a shipping container that I’m building an off grid system for. I have 2, Growatt SPF 5000 ES inverters purchased from Alibaba connected in parallel and a Growatt auto transformer that’s powering an outlet that’s jumping another outlet that’s in a metal box screwed into the shipping container.

Yesterday I finally finished wiring the system and powered the 2 outlets and everything was working fine till I turned off the circuit breaker and later my 5 year old daughter touched the shipping container and got zapped. I grabbed my multimeter and measured from the ground to live wire and even though the breaker that was feeding that live wire was in the off position and disconnected from the panel I showed a reading of 120v. This is extremely alarming because the whole case of the shipping container was energized due to the grounded metal box screwed to the shipping container! That’s an 40’ by 8’ area that’s energized by this live ground. I’m lucky my daughter was not seriously hurt by this.

I wired an independent ground all the way from the ground rod to the subpanel ( panel on the right) that it’s being fed by the auto transformers output wires and I still was getting a live ground reading.

Can anyone help? I need to figure out a solution to this live ground problem.

The picture below shows the 2 growatt inverters powering the panel on the Left.

A 30A breaker feeds the wires going through the panel on the right and straight up into the auto transformer on the “IN” side

On the output side you have the live1, neutral and live 2 wires going straight down to the panel on the right.

Then on that right panel you just have a 20A breaker that’s feeding the outlet on the right that’s jumping another outlet that’s in a metal box screwed to the shipping container.

Any constructive criticism is welcomed as well. I’m new to this Solar world and any suggestions to better my system is welcomed

 

[Joshua787]

Hi All,

I have a shipping container that I’m building an off grid system for. I have 2, Growatt SPF 5000 ES inverters purchased from Alibaba connected in parallel and a Growatt auto transformer that’s powering an outlet that’s jumping another outlet that’s in a metal box screwed into the shipping container.

Yesterday I finally finished wiring the system and powered the 2 outlets and everything was working fine till I turned off the circuit breaker and later my 5 year old daughter touched the shipping container and got zapped. I grabbed my multimeter and measured from the ground to live wire and even though the breaker that was feeding that live wire was in the off position and disconnected from the panel I showed a reading of 120v. This is extremely alarming because the whole case of the shipping container was energized due to the grounded metal box screwed to the shipping container! That’s an 40’ by 8’ area that’s energized by this live ground. I’m lucky my daughter was not seriously hurt by this.

I wired an independent ground all the way from the ground rod to the subpanel ( panel on the right) that it’s being fed by the auto transformers output wires and I still was getting a live ground reading.

Can anyone help? I need to figure out a solution to this live ground problem.

The picture below shows the 2 growatt inverters powering the panel on the Left.

A 30A breaker feeds the wires going through the panel on the right and straight up into the auto transformer on the “IN” side

On the output side you have the live1, neutral and live 2 wires going straight down to the panel on the right.

Then on that right panel you just have a 20A breaker that’s feeding the outlet on the right that’s jumping another outlet that’s in a metal box screwed to the shipping container.

Any constructive criticism is welcomed as well. I’m new to this Solar world and any suggestions to better my system is welcomed

 

[hwy17]

What was her feet on, outside on the earth? Barefoot or shoes? Do you think she was touching anything else with the other hand or just one hand to shipping container?

 

[rhino]

Might help reviewing this thread: https://diysolarforum.com/threads/growatt-spf-3000tl-lvm-es-48v-ground-issue.52968/

 

[Mattb4]

Probably need someone more familiar with a setup that uses autotransformer to have output than me. What the proper method and where to establish a NG bond after a transformer would need to be followed. My feelings would be to run a ground rod and bond the transformers output neutral. Also run a ground wire from this system ground to the shipping containers structure.

Hopefully one of the folks that run with a transformer can see this Thread and give you better guidance.

 

[finite]

Pic of how you grounded in the sub panel?.

 

[seneysolar]

Whats this connection? Green to black?

 

[Mattb4]

You have two Threads on this with slightly different Titles. Probably should ask a moderator to combine them.

 

[BentleyJ]

I'm seeing a green wire connected to a black wire with a red wire nut in that breaker panel on the lower left. Green or Green/yellow stripe is for ground.

Perhaps we should go through the whole wiring scheme device by device.

 

[finite]

When dealing with "sub"panels neutrals and grounds must be seprated and grounds must be bonded to metal bits. The neutral is your goundED conductor needed for function of the circuit, the green ground is your groundING conductor for safety.

I would def drive 2 ground rods no closer than 6' apart with a number 4/6 solid bare conductor and ground that container. I deal with transformers a lil bit and there case's must be grounded, your pics arent the best for getting in and seeing what is what so sorry i can be too specific. refer to the manufactors wiring diag but im sure they bonded there neutral inside the equip. Dont walk barefoot round that thing till you do.

Thus us how your grounds and neutrals should look in a sub panel fed from a transformer. Neutrals isolated from steel to keep the electrons required for circuit function find any other path to ground. Green wires bonded to all steel parts to give any electrons that get out a "short" path to ground.

 

[Joshua787]

Whats this connection? Green to black?
View attachment 206743

The angle the picture was taken makes it seem like it’s connected green to black but in fact it’s connected green to green.

 

[hwy17]

Detailed pictures of each panel and device wiring would help.

 

[Joshua787]

I'm seeing a green wire connected to a black wire with a red wire nut in that breaker panel on the lower left. Green or Green/yellow stripe is for ground.

Perhaps we should go through the whole wiring scheme device by device.

The angle the picture was taken makes it seem that way but green is connected to green.

 

[Supervstech]

If you are measuring 120V from live to ground, you have annenergized circuit somewhere...

 

[seneysolar]

Yeah its too hard to tell from pics.
Do you have a neutral/ground bond anywhere? Before the transformer?
Double and triple check that you don't have a Line and Neutral reversed.

 

[Supervstech]

Reading 120V from hot to ground is normal... it power is on. So find out where power is on.

I want to know what she was touching that shocked her.

Where was she, what was she in contact with.

 

[PreppenWolf]

Is solar hooked up to this? If so the case of the inverter is likely going to be energized. And if you don't have grounding rods it will energize the container.

 

[Supervstech]

Get good lighting, take pictures closeup and in focus.
Post them here.

 

[Hedges]

The first thing to understand is that wiring something to a ground rod is not the key part of safety. The key part is wiring all metal objects together.

The first (1) point that matters is that all metal chassis must have wires connecting them together (including between multiple trailers, storage containers etc.) "bonding"

The second (2) is that no currents from any circuits is allowed to flow through those bonding wires. All circuits have their own power wires and return (or "neutral") wires, forming a loop from source (battery or inverter) through loads and back to source. The circuits do not use "ground" or "bonding" wires to carry current.

The third (3) is to have one or more ground rods and connect the bonding wires from (1) to that ground rod. Also connect any pipes like water, gas, etc. All exposed metal is pulled to same voltage as the earth with ground rod.

A fourth (4) is to use GFCI outlets for any wet locations including outside. (not the issue in this case)

The shock may have occurred because a life wire had a path to the container your daughter touched. Alternatively, the container may have had a path to chassis of equipment, but a live wire had a path to earth, so earth and container were different voltages.

One of your photos shows PV panels on the roof of a container or trailer. This situation has caused shocks for a number of people because inverters like yours superimpose AC voltage on PV+/-. There is capacitance between PV cells and PV frames, causing high voltage but low current. For that reason, The First (1) rule to bond metal together, PV panel frames to container back to inverter chassis to building inverter is in and to a ground rod.

Then test everything on AC and DC scale, voltage to chassis and voltage to earth.

 

[Supervstech]

Some solar panels can leak energy into the case of the panel.
The case of EACH panel needs to be connected to a grounding conductor.