Grounding my container?

[Mannfamilywoodworks]

I’ve been pretty confused about two things with my system.
I have a 45’ shipping container.
I’m trying to keep it safe.

It’s powered by a growatt 6k AIO and an EG4 life power battery with 6 -235 watt panels in series.
My output from the growatt is 240v which supplies my AC electrical panel. L1-L2-N-G

from my panel I have a 6 gauge ground wire connected to a small bus bar.
That ground wire runs outside the container through the floor to a 6’ deep grounding rod.

Does all of that makes sense?
Does it sounds sufficient and safe?
Do I need to ground my container and run an additional 6 gauge wire to this grounding rod?



Secondly what is neutral ground bounding.
Why is it used in some instances but not others? Do I need it?
Does it complete the ground fault circuit? I’m not exactly sure. I’ve been told many different things.
Right now I do not have it bonded and it is working fine.


Lastly I have a 30amp -240v -input coming from my generator to a separate panel with separate breakers and outlets for backup.
This panel also has a small bus bar for all the grounds.
Do I connect this bus bar with a 6 gauge ground wire to the other grounds in the other panel?
Or do I put an additional 6’ ground rod in for this additional panel?

 

[FilterGuy]

It’s powered by a growatt 6k AIO and an EG4 life power battery with 6 -235 watt panels in series.
My output from the growatt is 240v which supplies my AC electrical panel. L1-L2-N-G

from my panel I have a 6 gauge ground wire connected to a small bus bar.
That ground wire runs outside the container through the floor to a 6’ deep grounding rod.

Does all of that makes sense?
Does it sounds sufficient and safe?
Do I need to ground my container and run an additional 6 gauge wire to this grounding rod?

Make sure there is a Solid connection someplace between the ground bus-bar and the container and you should be good.

Secondly what is neutral ground bounding.
Why is it used in some instances but not others? Do I need it?
Does it complete the ground fault circuit? I’m not exactly sure. I’ve been told many different things.
Right now I do not have it bonded and it is working fine.

What the above does not show is that the Utility also ties neutral to Ground. Consequently, if your system is tied to the utility you can still be the path from hot to ground even if you do not do a N-G bond locally.

I could not tell if you have any grid-tied into your system. If you do you should have a local N-G bond at the service entrance. (Note: NEC requires grounded netural for any circuit over 60V so you need an N-G bond/

What is the exact model number of your Growatt? We need to know if it is one of the ones that does dynamic N-G ground

Note: you may want to review this series of papers:

Grounding Made simpler - Part 1: AC/houshold grounding

To get the paper, click on the orange button at the top of the screen. The subject of grounding is a complex, multifaceted subject, that is often treated as an after-thought but needs to be considered from the beginning of the design and build...

diysolarforum.com

 

[Checkthisout]

Your neutral/ground bond should be in the Growatt.

You would treat it similar to how you treat a normal house with a backup generator where the transfer switch breaks the neutral/ground bond in the panel and moves it to the generator when the generator is running.

Your panels need to ground to your container/rod.

Your container needs to ground to your panel.

Your battery negative should ground to the panel.

More simply, your battery negative, container, your container, your panels, and your growatt's ground should all be electrically connected to each other and the nuetral/ground bond should be in the growatt.

Be careful. It sounds like you're running pretty high array voltage with 6 235 watt panels in series (240 volts or so?)

If your growatt uses a floating neutral then you need to bond the neutral in the panel.

 

[Mannfamilywoodworks]

Your neutral/ground bond should be in the Growatt.

You would treat it similar to how you treat a normal house with a backup generator where the transfer switch breaks the neutral/ground bond in the panel and moves it to the generator when the generator is running.

Your panels need to ground to your container/rod.

Your container needs to ground to your panel.

Your battery negative should ground to the panel.

More simply, your battery negative, container, your container, your panels, and your growatt's ground should all be electrically connected to each other and the nuetral/ground bond should be in the growatt.

Be careful. It sounds like you're running pretty high array voltage with 6 235 watt panels in series (240 volts or so?)

If your growatt uses a floating neutral then you need to bond the neutral in the panel.

Thankyou this is exactly what I needed to know.
I always try my best to be careful.

I have two separate ac breaker panels that aren’t connected so no backfeeding can occur so no need for the transfer switch.

How exactly do I ground the solar panels?

 

[Mannfamilywoodworks]

Make sure there is a Solid connection someplace between the ground bus-bar and the container and you should be good.


View attachment 110679

What the above does not show is that the Utility also ties neutral to Ground. Consequently, if your system is tied to the utility you can still be the path from hot to ground even if you do not do a N-G bond locally.

I could not tell if you have any grid-tied into your system. If you do you should have a local N-G bond at the service entrance. (Note: NEC requires grounded netural for any circuit over 60V so you need an N-G bond/

What is the exact model number of your Growatt? We need to know if it is one of the ones that does dynamic N-G ground

Note: you may want to review this series of papers:

Grounding Made simpler - Part 1: AC/houshold grounding

To get the paper, click on the orange button at the top of the screen. The subject of grounding is a complex, multifaceted subject, that is often treated as an after-thought but needs to be considered from the beginning of the design and build...

diysolarforum.com

Thankyou I’m going to check all of that out.
This is my specifications sheet for the inverter
Edit. My photos don’t load due to poor service in the woods

 

[Checkthisout]

How exactly do I ground the solar panels?

The metal frames of the panels should have a hole somewhere with a little grounding icon that accepts a green grounding screw. You can attach anywhere but it's easiest to use the place provided.

This connects to an appropriate grounding connector and then #6 bare copper which can run to all the panels and then in your case, attach to a spot on the container but it's probably just easier to run it directly down to the rod you have installed.

It needs to be electrically tied into all the other grounds which can be accomplished wherever including at the rod.

 

[SoakedUp]

The metal frames of the panels should have a hole somewhere with a little grounding icon that accepts a green grounding screw. You can attach anywhere but it's easiest to use the place provided.

This connects to an appropriate grounding connector and then #6 bare copper which can run to all the panels and then in your case, attach to a spot on the container but it's probably just easier to run it directly down to the rod you have installed.

It needs to be electrically tied into all the other grounds which can be accomplished wherever including at the rod.

I’ve seen conflicting info on this from this website. I thought panel grounds were supposed to be separate from service ground?

 

[Checkthisout]

I’ve seen conflicting info on this from this website. I thought panel grounds were supposed to be separate from service ground?

What if your panel shorts to the frame of the panel?

Would thus not make the frames electrically live without tripping fuses/breakers?

 

[SoakedUp]

What if your panel shorts to the frame of the panel?

Would thus not make the frames electrically live without tripping fuses/breakers?

Do the panels current carrying conductors connect to a breaker directly within the load center allowing for a breaker to even trip? A fuse may blow if you fuse your panels but that has nothing to do with the EGC from the panels. The panel EGC is purely for lighting strikes…or so I thought.

 

[Hedges]

PV panel internal conductors can be at 100V or 500V. In some cases, they ride on top of AC.
Short to frame would make frame a shock hazard. So I would want frames to have a copper or aluminum path back to ground system at the electronics. (not floating, not just a rod into the earth.)

Typically, current from PV panel will not be enough to trip a fuse. It can trip GFCI (often a 1A fuse or breaker), an cause system to shut off.

 

[Checkthisout]

Do the panels current carrying conductors connect to a breaker directly within the load center allowing for a breaker to even trip? A fuse may blow if you fuse your panels but that has nothing to do with the EGC from the panels. The panel EGC is purely for lighting strikes…or so I thought.

Grounding RODS are not the same as EGC. The purpose of the EGC is not to connect the components to earth, its to provide a current path back to the source in the event of a fault. If that makes sense? It's to provide a way to blow a fuse and prevent stray currents (faults) from electrifying the cases of the equipment.

Ground RODS are for lightning and possibly static etc.

High voltage panels (I think the cutoff is 50 volts) should be grounded back to whatever they are supplying and ultimately grounded to everything else in the system. In this case the op has a metal container which needs to be grounded for the same reason you ground mobile home frames.

As far as blowing the fuse if solar positive contacts the solar frame, your solar negative (I think I didn't mention that above) should be bonded to the EGC as well. This will blow the fuses or breaker if you have them or help start a fire if they aren't.

 

[Checkthisout]

I think in some cases bonding the battery negative to the EGC depends on the equipment. You should but this will damage some inverters so don't. Manufacturer should specify.

 

[Mannfamilywoodworks]

The metal frames of the panels should have a hole somewhere with a little grounding icon that accepts a green grounding screw. You can attach anywhere but it's easiest to use the place provided.

This connects to an appropriate grounding connector and then #6 bare copper which can run to all the panels and then in your case, attach to a spot on the container but it's probably just easier to run it directly down to the rod you have installed.

It needs to be electrically tied into all the other grounds which can be accomplished wherever including at the rod.

Thankyou I had no idea about grounding the panels. A friend of mine called yesterday and said he had special grounding connections for the panels to all ground to one another. I’m waiting for him to come up next weekend to complete that

 

[Mannfamilywoodworks]

Do the panels current carrying conductors connect to a breaker directly within the load center allowing for a breaker to even trip? A fuse may blow if you fuse your panels but that has nothing to do with the EGC from the panels. The panel EGC is purely for lighting strikes…or so I thought.

There’s a breaker but it’s 63amps. I should’ve probably got a 20amp breaker. This one is way to big.

 

[Mannfamilywoodworks]

W

I think in some cases bonding the battery negative to the EGC depends on the equipment. You should but this will damage some inverters so don't. Manufacturer should specify.

Whats an EGC? I’ll confirm with manufacturers about grounding the battery

Edit : spelling correction

 

[Checkthisout]

W

Whats an EGC? I’ll confirm with manufacturers about grounding the battery

Edit : spelling correction

The ground wire. The third prong on plugs, the bare copper in romex, the bare copper wire in your breaker panel, the wire you attach to the outside case of your solar equipment...........sometimes it's denoted as green wire....green wire nuts

Equipment Grounding Conductor.

 

[Checkthisout]

Neutral Ground bonding is where connect your EGC (bare or green copper wire) to your Neutral (white) wire.

 

[Checkthisout]

Also, read the manual for your unit. It may not want you to ground the pv negative or battery negative. It will also tell you if the neutral and ground are bonded in the unit.

 

[Hedges]

There’s a breaker but it’s 63amps. I should’ve probably got a 20amp breaker. This one is way to big.

63 amps - is that rated for AC, or for DC?

Breaker sized to carry current from a single PV string will never trip. Three PV strings connected in parallel, each through a breaker (or one pole of a ganged beaker), if one string shorts to frame then current from two other strings may trip breaker. More than two, likely to trip.

PV panel label will say what size breaker is maximum allowed (for the purpose of protecting multiple parallel strings.)
Minimum size breaker should be at least Isc x 1.56.
Wire ampacity should be at least as high as breaker. In the case where you use an oversize breaker as array disconnect, wire ampacity should be at least 1.56 times Isc x number of strings in parallel.

Those multiples are for thermal-magnetic breakers. We always oversize 1.25x from continuous operating current. For PV, another 1.25x (giving 1.56x) for cloud-edge effect causing current higher than Isc.

Magnetic-hydraulic breakers, often used for PV DC, don't need 1.25x for thermal variations. Some are guaranteed not to trip below 105% of rating, while others guaranteed not to trip below 100% of rating.

 

[SoakedUp]

Grounding RODS are not the same as EGC. The purpose of the EGC is not to connect the components to earth, its to provide a current path back to the source in the event of a fault. If that makes sense? It's to provide a way to blow a fuse and prevent stray currents (faults) from electrifying the cases of the equipment.

Yes. This makes sense and I already understood that. If the source of power is the panels. How does a EGC from the solar panels that goes to the grounding rod help provide a current path back to the source (in this case the the solar panels on top of a shipping container)? Typically DC and AC systems are are kept separate, no?

Ground RODS are for lightning and possibly static etc.

High voltage panels (I think the cutoff is 50 volts) should be grounded back to whatever they are supplying and ultimately grounded to everything else in the system. In this case the op has a metal container which needs to be grounded for the same reason you ground mobile home frames.

Grounding the container on the AC side makes sense. But if the panels are insulated from the container on top they would be a separate system. Let’s say the solar panels go directly to an AIO inverter. The case of the AIO has a EGC to the rod(or to a AC distribution panel which has a EGC to the rod) but the AIO is NG bonded on the AC side. Wouldn’t the solar positive and negative be separate. So even if you have a DC breaker between the solar panels and the AIO the ground has no bond to the negative side of the solar current carrying conductor.

As far as blowing the fuse if solar positive contacts the solar frame, your solar negative (I think I didn't mention that above) should be bonded to the EGC as well. This will blow the fuses or breaker if you have them or help start a fire if they aren't.

Where would you make this bond between the solar negative and EGC? I guess this is where I’m getting confused because the majority of systems I’ve seen don’t show or atleast it isn’t obvious where this bond is taking place.