Seeking input for possible change array to charge controller wiring

[timselectric]

Wire nut, it is then.

If I recall you said the blue ideal nuts would be the correct choice to splice a 6awg to 10awg?

You can use a standard ideal blue, and squirt some silicone in after, to weatherproof it.

 

[Nan_wpg]

You can use a standard ideal blue, and squirt some silicone in after, to weatherproof it.

Any issue connecting the array EGC directly to my grounding rod(s)? Just looking at things and the rods are closer than my “solar shed” and I happen to have a length of pv wire that will reach. I can clamp it in with the GEC at one of the rods.

 

[timselectric]

Any issue connecting the array EGC directly to my grounding rod(s)? Just looking at things and the rods are closer than my “solar shed” and I happen to have a length of pv wire that will reach. I can clamp it in with the GEC at one of the rods.

Nope, that's fine.
Everything connected to the grounding system becomes part of the grounding system. And can be a connection point for future EGC's.
As long as the path back to the N/G bond is adequate for what is being added.

 

[Nan_wpg]

Nope, that's fine.
Everything connected to the grounding system becomes part of the grounding system. And can be a connection point for future EGC's.
As long as the path back to the N/G bond is adequate for what is being added.

Out of curiousity, why the need to tape/silicone the wire nut when transitioning from 6awg to 10awg at my array, but not at the ground rod? Is it because the ground rod is ground?

 

[timselectric]

Out of curiousity, why the need to tape/silicone the wire nut when transitioning from 6awg to 10awg at my array, but not at the ground rod? Is it because the ground rod is ground?

That's a good question.
I never thought about it, because it gets buried. (Out of sight, out of mind)
It's not really a very important connection to me. The earth itself isn't a very good conductor, unless it's wet. And when wet, all connections are better.

 

[Nan_wpg]

That's a good question.
I never thought about it, because it gets buried. (Out of sight, out of mind)
It's not really a very important connection to me. The earth itself isn't a very good conductor, unless it's wet. And when wet, all connections are better.

Ground IS an important connection, right?

More random thinking…… is it a good thing to burry the ground rods? Where I live there’s frost, and ground heaving. How do I know that the ground connection hasn’t broken off? Unless the rods are driven below the frost line. Wouldn’t it be prudent to not bury the ground rods completely (maybe have them slightly above ground for visual inspection?

 

[timselectric]

Ground IS an important connection, right?

Electrical grounding is the most important part of a system.
But this has little to do with the connection to earth.
The electrical grounding system begins at and is created by the N/G bond.

More random thinking…… is it a good thing to burry the ground rods? Where I live there’s frost, and ground heaving. How do I know that the ground connection hasn’t broken off? Unless the rods are driven below the frost line. Wouldn’t it be prudent to not bury the ground rods completely (maybe have them slightly above ground for visual inspection?

I never leave them exposed (after inspection).
It's a trip hazzard and will ruin a lawnmower blade.
It's never been an Issue. And I have dug them up years later.

 

[Nan_wpg]

Electrical grounding is the most important part of a system.
But this has little to do with the connection to earth.
The electrical grounding system begins at and is created by the N/G bond.

I never leave them exposed (after inspection).
It's a trip hazzard and will ruin a lawnmower blade.
It's never been an Issue. And I have dug them up years later.

My system has currently no ground rods, or GEC. It does have a circuit, with a breaker, and it has a N/G bond. So it will still trip a breaker and clear a fault? I thought you needed the connection to earth for the whole thing to work? What’s the point,of,earth connection then? (I do need that for my spd’s)

 

[timselectric]

My system has currently no ground rods, or GEC. It does have a circuit, with a breaker, and it has a N/G bond. So it will still trip a breaker and clear a fault? I thought you needed the connection to earth for the whole thing to work?

The N/G bond is what trips a breaker when there is a short to ground.

What’s the point,of,earth connection then?

it serves two purposes.

1. Makes the local earth safe, in relation to your electrical system.

2. It dissipates atmospheric (static) charge on the grounding system.

I do need that for my spd’s

Yes
Mother nature's electricity always seeks the earth.

Generated electricity, must flow in a circuit (Circle) back to the source.

 

[Nan_wpg]

The N/G bond is what trips a breaker when there is a short to ground.

it serves two purposes.

1. Makes the local earth safe, in relation to your electrical system.

2. It dissipates atmospheric (static) charge on the grounding system.



Yes
Mother nature's electricity always seeks the earth.

Generated electricity, must flow in a circuit (Circle) back to the source.

Tim can I run thwn under the cabin, attached to the cabin without conduit if it’s the EGC? Looking under the cabin I can run my array EGC to an existing box where power enters the cabin. That box IS connected to the grounding system.

 

[Nan_wpg]

Nope, that's fine.
Everything connected to the grounding system becomes part of the grounding system. And can be a connection point for future EGC's.
As long as the path back to the N/G bond is adequate for what is being added.

Does that mean I have to upgrade my inverter wiring? We only have one circuit in the cabin. 12/2. Everything to and from the inverter is 12/2. My array EGC is 10awg. I could run a 6g EGC from inverter to the ground bus. (N/G bond is currently in the inverter).

If I disable the inverter N/G bond and bond in my small electrical panel THAT wire is 12/2 so the path to N/G bond would be smaller (probably 2 feet).

Not sure if it matters (or if I’m going to make sense) but my 4 solar panels will be wired in series but wire,was sized for parallel (10g). So maybe the 12/2 bottle neck would be ok?

 

[timselectric]

Tim can I run thwn under the cabin, attached to the cabin without conduit if it’s the EGC? Looking under the cabin I can run my array EGC to an existing box where power enters the cabin. That box IS connected to the grounding system.

Yes
The EGC does not need to be in conduit. As long as it's not exposed to physical damage.

 

[timselectric]

Does that mean I have to upgrade my inverter wiring? We only have one circuit in the cabin. 12/2. Everything to and from the inverter is 12/2. My array EGC is 10awg. I could run a 6g EGC from inverter to the ground bus. (N/G bond is currently in the inverter).

If I disable the inverter N/G bond and bond in my small electrical panel THAT wire is 12/2 so the path to N/G bond would be smaller (probably 2 feet).

Not sure if it matters (or if I’m going to make sense) but my 4 solar panels will be wired in series but wire,was sized for parallel (10g). So maybe the 12/2 bottle neck would be ok?

If #10 is the largest current carrying conductor.
#10 is the largest EGC needed anywhere in the system.
Larger isn't required. But Larger is always acceptable.

Edited for correction.

 

[Nan_wpg]

Yes
The EGC does not need to be in conduit. As long as it's not exposed to physical damage.

This, I like to hear. Easy peasy now.

Edited: much sad, much cry, lol

 

[Nan_wpg]

If #10 is the largest current carrying conductor.
#12 is the largest EGC needed anywhere in the system.
Larger isn't required. But Larger is always acceptable.

EGC needed is always 1 size bigger than largest current carrying conductor? (I’m thinking you already mentioned this in one of my hundred posts, sorry if you did)

 

[timselectric]

EGC needed is always 1 size bigger than largest current carrying conductor? (I’m thinking you already mentioned this in one of my hundred posts, sorry if you did)

No
#12 is Smaller than #10.
The EGC size is based on the OCP of the circuit.
Or in the case of PV circuits, it's based on what the OCP would be if it were required.

Edit:
You need #10
Not #12

 

[Nan_wpg]

No
#12 is Smaller than #10.
The EGC size is based on the OCP of the circuit.
Or in the case of PV circuits, it's based on what the OCP would be if it were required.

Edit:
You need #10
Not #12

No
#12 is Smaller than #10.
The EGC size is based on the OCP of the circuit.
Or in the case of PV circuits, it's based on what the OCP would be if it were required.

Edit:
You need #10
Not #12

Typo, I meant smaller. So looks like I have to rewire my whole system with 10/2. I ran 12/2 as that’s all we needed for the ac side. and I thought since my array EGC went to the ground bus that 10g is ok. I didn’t realize it has to be 10g all the way to the N/G bond because I thought the EGC was just to “get to the ground rod”

I think we’re doing a us day trip this weekend. May as well get the ground rods. 8’ is ok or should I,go 10’?

 

[Nan_wpg]

If #10 is the largest current carrying conductor.
#10 is the largest EGC needed anywhere in the system.
Larger isn't required. But Larger is always acceptable.

Edited for correction.

Does that include the battery to inverter cables? Mine are 1/0 I think. Was,also going to use 8g from charge controller to battery. The choice for,8g was not for current, but for voltage drop

 

[timselectric]

Typo, I meant smaller. So looks like I have to rewire my whole system with 10/2. I ran 12/2 as that’s all we needed for the ac side. and I thought since my array EGC went to the ground bus that 10g is ok. I didn’t realize it has to be 10g all the way to the N/G bond because I thought the EGC was just to “get to the ground rod”

I think we’re doing a us day trip this weekend. May as well get the ground rods. 8’ is ok or should I,go 10’?

I wouldn't worry about it.
#12 will be fine.
Assuming that your largest AC breaker is 20a.

 

[timselectric]

Does that include the battery to inverter cables? Mine are 1/0 I think. Was,also going to use 8g from charge controller to battery. The choice for,8g was not for current, but for voltage drop

No
You are only protecting against AC fault current.

 

[Nan_wpg]

I wouldn't worry about it.
#12 will be fine.
Assuming that your largest AC breaker is 20a.

The breaker is 15A. (Cabin wiring is 14/2).

 

[Nan_wpg]

No
You are only protecting against AC fault current.

So, if that doesn’t include the battery cable, then why include the pv wire if we are only protecting for ac fault current?

So basically the EGC is (usually) the same size as the conductors it’s accompanying, and so long as its path to the N/G bond is big enough it’s ok?

Normally I’d put a 6awg from inverter to ac panel box , so whether I N/G bond at the inverter or the panel the path is good enough. But in my case I only needed 12/2

 

[timselectric]

So, if that doesn’t include the battery cable, then why include the pv wire if we are only protecting for ac fault current?

The battery cables are always more than large enough.
But the PV conductors can be much smaller than what would be required for the available fault current.
But it would be pointless to use a huge EGC for the PV circuits if the PV conductors are smaller.
So, it's sized normally, from the EGC table.

So basically the EGC is (usually) the same size as the conductors it’s accompanying, and so long as its path to the N/G bond is big enough it’s ok?

Normally I’d put a 6awg from inverter to ac panel box , so whether I N/G bond at the inverter or the panel the path is good enough. But in my case I only needed 12/2

Here's the table.

 

[robbob2112]

Tim,

Please clear him up on connecting the negative pole of the battery to the ground. He is arguing for it in thus thread.

Off Grid Cabin Design - Grounding Question

I am designing a 48V solar system for my off-grid cabin. I am using a Victron charge controller and Multiplus II. I have a question about grounding. I have looked at many resources but my head is spinning as it seems some of the information is inconsistent. I am hoping someone can set me on the...

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