No grid grounding/bonding

[Nan_wpg]

I’ve been learning and maybe this is way over thinking…..

our cabin is no grid. We are essentially the power company.

power company does its own grounding/bonding, then transmits. Homeowner grounds and bonds at the home.

so, should I also ground/bond the inverter on its own, and then ground/bond our cabin? I know you only,bond at one location only (at or before first disconnect).

my inverter is right next to the panel (it will be).

if I only bond/ground at one point is it better to,bond at the inverter, or panel? if I bond at the panel what happens if there’s a problem with the inverter? (If the inverter has an issue the fault will find its way along the EGC to the panel bond?)

hope that makes sense.

 

[Adam De Lay]

Ultimately it depends on what inverter you're talking about. Personally I think its easiest to set up the G/N bond in the panel.

Edit for correction: Assuming you have a ground from the inverter to the main panel, any fault will travel back to the main panel in order to find its way back to the source.

 

[AZ Solar Junkie]

Ultimately it depends on what inverter you're talking about. Personally I think its easiest to set up the G/N bond in the panel. Assuming you have a ground from the inverter to the main panel, any fault will find its way back there and then go to earth.

I agree - a physical bond in your panel is better than relying on the N-G bond relay in the inverter. Much easier for the inverter to malfunction than a physical bonding screw in the panel ??

 

[timselectric]

The mai panel is the easiest.
As long as the inverter doesn't do it for you. Or it allows you to defeat it from doing it.

 

[johnnysolar]

Ooh, can you elaborate on why a ground rod is needed and the theory behind having one and not? My understanding is it can be part of a circuit, so if you have a rod when not necessary, it could make it so you become part of the circuit when you touch some stuff. Example, my motorhome has no ground rod and no ground neutral bond at that (floating neutral) generator is an onan 7500 3cyl diesel. Also no neutral ground bond. If there was a neutral ground bond and a ground rod involved, increased danger follows, yeah? I guess what I'm saying is be careful using ground rods when not necessary. Two vids below worth watching on the subject. Think safety, be safety.

 

[hwy17]

The most serious off grid inverters, XW's, Rosie, etc. all do not have bonding provisions and expect the bond to be made in the panel. So I would go with that design, no matter what you're starting with.

I never thought a lot about ground faults in the inverter. Yes they would fault through the panel though.

 

[timselectric]

Assuming you have a ground from the inverter to the main panel, any fault will find its way back there and then go to earth.

For clarification.
Static and lighting seek to go to earth.
Electrical faults seek to go back to the source.

 

[hwy17]

If there was a neutral ground bond and a ground rod involved, increased danger follows, yeah?

Some electrical grounding schemes have agreed with this. Like the IT grounding system. It was considered a safety feature that no single phase to ground fault could shock you. The problem is the first phase to ground fault can go unnoticed, so you end up with an unintentionally grounded conductor that wasn't designed for.

Anyway, it's best to just treat RV and stationary applications as two different worlds and not try to transpose logic from one to the other.

 

[Adam De Lay]

For clarification.
Static and lighting seek to go to earth.
Electrical faults seek to go back to the source.

Thanks Tim. Still early and not enough coffee…

 

[Steve_S]

OVERTHINK and can cause yourself HEAPS of trouble.
Power Co / Grid is irrelevant.
Our Electrical Code like in the US has very specific rules on Grounding !

AC gets ONE Ground Point, Either a Ground Rod or Plate (24" from building & 30" deep) that runs to the Main AC Panel.
All AC Wires are then grounded there, with bonding through the circuits.
More than 1 Ground can cause loops and other faults, this often kills CGFI Plugs too ! *

* There IS a difference between GFI, CGFI, GCFI and of course Breakers (which is not the preferred option that inspectors want to see. Our code now wants Bathrooms & Kitchen Outlets protected. In Ontario they even extend that to Bedrooms !

My own system (see 1st link in my signature (terribly out of date for now) has ONE AC Ground, I used my 6", 25' Well casing that is sealed into Banded Granite as my AC Ground. My AC Gear & Inverter/SCC etc are grounded to this. My Solar Arrays are on a Wood ground Mount but use the aluminum rails etc, so that frame & Panels are also grounded for a lightning ground. NOTE that some places will not allow a Well Casing to be used as a ground. Not sure if Manitoba is one of those.,

SPD's ARE NEEDED !
Surge Protection Devices are needed on the DC & AC Side when setup like this. The BEST out there come from Midnite Solar and they will visually indicate if something went bad... NOTE: Not an item to cheap out on ! They can save your ass !

Category Products - MidNite Solar's

MidNite Solar Category Products.

www.midnitesolar.com

Now go look at the Canadian Electrical Code and the Manitoba Code Book.

Electrical codes and standards

Find out what permits and inspections are required for electrical installations. Follow electrical and wiring codes for construction, installation, and maintenance.

www.hydro.mb.ca

https://www.hydro.mb.ca/docs/permits/residential_wiring_guide.pdf

HUMAN ENGLISH FRIENDLY:
https://psknight.com/residential Covers all provinces too !

While you may not need Inspections for the Grid Connection as that is not a factor... INSURANCE Companies want their own inspections for coverage. A few will NOT touch offgrid and some run from anything DIY. CoOperators is "reasonable" while StateFarm is NASTY BAD ! Check what YOUR Insurance co wants !!!

 

[timselectric]

Anyway, it's best to just treat RV and stationary applications as two different worlds and not try to transpose logic from one to the other.

100%

 

[johnnysolar]

Transpose logic? Any logic I imply is that grounding is grounding, earth is earth and electricity is electricity and look at one example of an RV to get thinking about the why..... Watch the two videos Mike Holt has that I linked. They are important. Let's make sure we understand what and why we are doing something, is my point and logic. I saw mention of "any fault will find its way back there and then go to earth." and was seeing a red flag given the incomplete info. In that case it only goes to earth to return to the source. Don't become part of that source because of improper use and installation of earth grounding rods. It can happen, it doesn't take much and it can be tragically , avoidably lethal.

 

[timselectric]

can you elaborate on why a ground rod is needed and the theory behind having one and not?

The purpose of a grounding system is to make everything safe to touch. (Without getting shocked)
A ground rod connected to the grounding system, makes the earth safe to touch.

My understanding is it can be part of a circuit, so if you have a rod when not necessary, it could make it so you become part of the circuit when you touch some stuff.

There should only be one connection between earth and your grounding system, for this reason.

 

[johnnysolar]

The purpose of a grounding system is to make everything safe to touch

False. Seriously watch Mike's video. 58:30, 1:01:34 are two highlights on this subject but the whole video needs to be watched in entirety. It may make the situation for equipment safe in certain situations vs not having system grounding for electrical impedance from a nearby lighting strike can cause serious issues. The whole video should be watched.

 

[timselectric]

False.

You must be misinterpreting something, somewhere.
I have followed Mike Holt for many years.
He would never tell you to not ground a stationary system.
Or to not connect the earth to a stationary system.
He will tell you that Auxiliary ground rods are a bad idea.

 

[johnnysolar]

misinterpreting something

? That I think is you right now moreso than I. *Who* said "don't install a ground rod"? Because it sure wasn't me. Read only the words written please. Can I get a amen to watching those two videos I said should be watched? Because I definitely said that.

 

[johnnysolar]

The purpose of a grounding system is to make everything safe to touch. (Without getting shocked)

To follow up for clarity, this statement is false. There are two time stamps that I highlighted where Mike Holt even points this out. Watching the whole video is necessary however I wanted to point out those two areas because the video focuses on that very statement, which I am calling false. It's not to make things safe to touch.

 

[timselectric]

Who* said "don't install a ground rod"?

If there was a neutral ground bond and a ground rod involved, increased danger follows, yeah?

 

[timselectric]

To follow up for clarity, this statement is false. There are two time stamps that I highlighted where Mike Holt even points this out. Watching the whole video is necessary however I wanted to point out those two areas because the video focuses on that very statement, which I am calling false. It's not to make things safe to touch.

You are definitely misinterpreting the information.
The first time stamp you posted is pertaining to auxiliary ground rods.
The second time stamp you posted actually has nothing to do with grounding. It pertains to the misuse of welding equipment.

 

[johnnysolar]

With regard to making a neutral ground bond in my motorhome and also driving a ground rod, connecting the two It's all right there. Would that be dangerous? yeah? It's good to know why and is applicable to OPs question. Nowhere did I say "don't drive a ground rod". I did share two unbelievably useful resources. If you read "don't drive a ground rod" from my statement...... I mean, those were not words I used.