Can I use thhn wire for ground/earth and bury it?

[doox00]

50 to 60 feet would cost $35 to $45 for 3/4" PVC SCH 40 for underground and an additional $12 for the SCH 80 needed above grade. The 15 feet is a no brainer.

Penny wise and pound foolish is no way to go thru life. If that amount for conduit will break you...........

I just trenched in 240 feet of 2" SCH 40 PVC plus needed 15 feet for the SCH 80 ends. I also trenched in 130 feet of 1.5" SCH 40 and an additional 20 feet of SCH 80 for the shop system. 2 years ago I trenched in 420 feet of 1.5" from array to house.

The 2" will only contain four 10AWG AC current carrying conductors at this stage. Down the road, I might run 4/0 and the conduit will be large enough.

Plan ahead, spend the money once and wisely, you forget about what it cost yesterday when you need to pull wire again or change the system.

It has nothing to do with the money, just never occurred to me to put it in conduit since I had direct bury wire. I have put 50k cash into this project, a couple hundred bucks makes no difference but like I said it never occurred to me. If I have an issue later then I will take an hour to dig the trenches again with the excavator and a day to run new lines and conduit. If I don't ever have an issue then good for me.

 

[jzampieron]

Lighting protection is a completely different system.
Built above and around what you want to protect. Never connected to or through what you want to protect.

Not sure why folks think grounding is going to provide lightening protection. Very common misconception.

SPDs with proper grounding may mitigate some damage during an indirect/nearby strike... protection against direct strikes is something else entirely.

In a direct strike do you really think a little 6 AWG copper wire is going to do anything where there is enough energy to cause large trees to explode? If we ever have a direct strike on the house or array I basically hope just for the family to survive it. Whatever's left will need to be rebuilt salvaging pieces.

That said, with all the tall trees nearby and large high-voltage electrical towers... a direct strike is almost impossible b/c the arc would form to one of those taller things before our house or array.

 

[Bluedog225]

I got a little confused here but think I’ve figured it out.

Am I close?

Tagging Tim because I’m quoting him.

@timselectric

For the grounding electrode conductor (GEC):
-stranded
-insulated
-rated for direct burial (this is why thhn isn’t appropriate)
-supplemental protection as needed
-continuous from ground rod(s) to main panel
-sized to this chart

 

[timselectric]

I got a little confused here but think I’ve figured it out.

Am I close?

Tagging Tim because I’m quoting him.

@timselectric

For the grounding electrode conductor (GEC):
-stranded
-insulated
-rated for direct burial (this is why thhn isn’t appropriate)
-supplemental protection as needed
-continuous from ground rod(s) to main panel
-sized to this chart


View attachment 252850

That chart is for an EGC (Equipment Grounding Conductor). Not a GEC (Grounding Electrode Conductor).

In almost all residential cases, the GEC to ground rod/s is a #6 copper.

 

[Bluedog225]

Dang it!

 

[Bluedog225]

At this rate, I’m going to fail my apprenticeship.

 

[timselectric]

At this rate, I’m going to fail my apprenticeship.

Nope, you are making great strides.

 

[Bluedog225]

Maybe this.

But I don’t know why they say “(AWG/kcmil)” then list what looks like AWG.

I think this tells me that use the inverter rating to determine my largest conductor size. E.g.: two 5000/48 Quattros; 10,000 watts; 83 amps. 15% headroom. So 95.5 amps. Round to 100 amps. For 100 amps I need 3 AWG wire. From the chart grounded with 8 AWG copper.

Note 1-Nobody rely on this. I know nothing.
Note 2-I’ve seen a version where the words “Service-Entrance” were struck.

 

[agtcovert]

Since I also need to do this: if THHN is protected in appropriate conduit (buried or above ground), is that then considered compliant or would it still be considered a violation?

 

[timselectric]

Since I also need to do this: if THHN is protected in appropriate conduit (buried or above ground), is that then considered compliant or would it still be considered a violation?

Compliant, yes.
But I would recommend pvc conduit.
If metal conduit is used, the conduit must also be bonded at both ends.