Where to put grounding rods?

[MartyByrde]

Hi, I am building an off grid solar trailer. All of the components will be inside of the enclosed trailer including the combiner boxes for easy access. My plan is to ground the main AC panel box and frame of the trailer to an 8ft copper rod directly outside the trailer.

My question is around whether or not the solar panel arrays should have their own grounding rod? They will be at varying distances, some will be within 5 feet of the trailer, some will be up to 30 feet away. Should I just run the copper wire from the arrays to the grounding rod outside the trailer?

Maybe I don’t need to ground the panels at all?

Appreciate any help and insight.

 

[timselectric]

Panel frames must be grounded. All grounding is routed back to the main ground bar. And a single #6 wire is ran to a ground rod. Ground rod should be as close to the main ground bar as possible.

 

[Bobert]

Hi, I am building an off grid solar trailer. All of the components will be inside of the enclosed trailer including the combiner boxes for easy access. My plan is to ground the main AC panel box and frame of the trailer to an 8ft copper rod directly outside the trailer.

My question is around whether or not the solar panel arrays should have their own grounding rod? They will be at varying distances, some will be within 5 feet of the trailer, some will be up to 30 feet away. Should I just run the copper wire from the arrays to the grounding rod outside the trailer?

Maybe I don’t need to ground the panels at all?

Appreciate any help and insight.
View attachment 106429

I’m interested in this as well. It’s my understanding that grounding the frame and panels would be fine but in so doing you would also need to bond the neutral to ground or the outgoing ac but it must be not bonded if attached to a system that has it’s own bond. I’m not sure how that’s supposed to be done.

 

[MartyByrde]

Panel frames must be grounded. All grounding is routed back to the main ground bar. And a single #6 wire is ran to a ground rod. Ground rod should be as close to the main ground bar as possible.

Thanks for the reply. What if the grounding bar in the panel box does not have enough grounding screw slots?

 

[Steve_S]

Panel frames must be grounded. All grounding is routed back to the main ground bar. And a single #6 wire is ran to a ground rod. Ground rod should be as close to the main ground bar as possible.

Slap slap wtf !!!!


Good God NO.
DO NOT EVER BOND SOLAR PANELS TO POWER GROUND !!!!!

The Solar Panel Frames, Racking and That hardware must be grounded for
LIGHTNING PROTECTION ONLY ! it is NOT ELECTRICAL !

USE #8 green jacketed ground wire connected to the lugs on the panels and rails and run that down to a proper grounding rod or plate. Zinc coated. The rod "must" be 30" from your rack or structure. The head can be buried at least 6" deep OR be a minimum of 6" above grade for visibility and marked.

A grounding "plate (also zinc coated) can also be used and must be 30" from structure and buried 30" deep.

AC grounding uses the same rules for depth and distance from structure, unless issuing a foundation embedded group is n the concrete (many do not accept that). Many regions allow a steel water pipe exiting house into soil as a grounding point. Most also allow the water well casing as a ground point.

Lightning and electrical grounds Must be distanced and independent, 6 feet is the general rule.

AC GROUND WIRE is generally #6, green jacket is pretty much demanded now But some still allow bare copper from main service panel to earth.

All AC wires, panels & subpanels must be bonded so they are connected to the main panel and out to earth. Ground " loops" with multiple ground rods/plates are to be avoided.

These are rules that are looked at during TSSA. Inspections.

I've built new, renovated old homes and installed a LOT of solar all which pass muster without fail.

Hope it helps, good luck....
And Holy crap, all this without coffee #1 yet... Dag nabbit.

 

[Bobert]

Good god NO.
DO NOT EVER BOND SOLAR PANELS TO POWER GROUND !!!!!

The Solar Panel Frames, Racking and That hardware must be grounded for
LIGHTNING PROTECTION ONLY ! it is NOT ELECTRICAL.
Slap slap wtf !!!!

I have a travel trailer when the trailer is connected to shore power the frame of the trailer is connected to the ground of the electrical system. So if the panels are grounded to the frame of the trailer the panels are grounded to the electrical system. Not sure how to safely get around that fact.

 

[Steve_S]

On a trailer/RV panels are floating... A vehicle is isolated by virtue of being on rubber, not a lightning attractor.

Much like if a powerline falls on the ground when your in a car,you are insulated from it by the tires.

Beware of of internet names/titles. The mean zilch.

Also reread my complete reply above.

 

[Bobert]

On a trailer/RV panels are floating... A vehicle is isolated by virtue of being on rubber, not a lightning attractor.

Much like if a powerline falls on the ground when your in a car,you are insulated from it by the tires.

Beware of of internet names/titles. The mean zilch.

Also reread my complete reply above.

When a travel trailer is connected to shore power the frame of the trailer and all components grounded to that frame are connected to the ground servicing the electrical panel Which is bonded to earth ground through the shore power connection. To ground a trailer with a separate ground rod is to greate a second ground in that situation. In my situation my solar array is on the roof of my travel trailer and mechanically bonded to the frame of the trailer. When I am connected to shore power my array is grounded to the ac electrical system and bonded to neutral whether I like it or lump it.

 

[Bobert]

Hi, I am building an off grid solar trailer. All of the components will be inside of the enclosed trailer including the combiner boxes for easy access. My plan is to ground the main AC panel box and frame of the trailer to an 8ft copper rod directly outside the trailer.

My question is around whether or not the solar panel arrays should have their own grounding rod? They will be at varying distances, some will be within 5 feet of the trailer, some will be up to 30 feet away. Should I just run the copper wire from the arrays to the grounding rod outside the trailer?

Maybe I don’t need to ground the panels at all?

Appreciate any help and insight.
View attachment 106429

I missed that you have ground mount arrays. How many volts is your array’s VOC?

 

[Shimmy]

Slap slap wtf !!!!


Good God NO.
DO NOT EVER BOND SOLAR PANELS TO POWER GROUND !!!!!


LIGHTNING PROTECTION ONLY ! it is NOT ELECTRICAL !

These are rules that are looked at during TSSA. Inspections.

The US is the opposite, although there was a period where it was more ambiguous. Bonding of a PV array is for shock protection and not lighting protection.

 

[HRTKD]

I missed that you have ground mount arrays. How many volts is your array’s VOC?

Does it matter if the arrays aren't permanently mounted? From the picture, it looks like they're not mounted on poles but deployed on the ground.

My ground deployed panels that I use with my RV have aluminum frames that are on the ground and those frames are held down with four 10" lag screws. I don't know if that counts as a ground or not. It if does, it was unintentional.

 

[Shimmy]

Does it matter if the arrays aren't permanently mounted? From the picture, it looks like they're not mounted on poles but deployed on the ground.

My ground deployed panels that I use with my RV have aluminum frames that are on the ground and those frames are held down with four 10" lag screws. I don't know if that counts as a ground or not. It if does, it was unintentional.

Personally, I would bond them back to the RV, although it isn't required.

A 10" lag screw isn't going to provide much in the way of a ground rod unless the soil is quite wet.

 

[timselectric]

Slap slap wtf !!!!


Good God NO.
DO NOT EVER BOND SOLAR PANELS TO POWER GROUND !!!!!

The Solar Panel Frames, Racking and That hardware must be grounded for
LIGHTNING PROTECTION ONLY ! it is NOT ELECTRICAL !

Lightning protection is completely different from electrical grounding.

All metal enclosures, frames, and structures are covered under electrical system grounding in the NEC.

Lightning protection should never be connected to what you are trying to protect.
It's a separate system installed above and around what you are trying to protect.

Just because you managed to pass an inspection, doesn't make it safe and correct. It just means that the inspector doesn't know how to properly do their job.

 

[timselectric]

Thanks for the reply. What if the grounding bar in the panel box does not have enough grounding screw slots?

Add another bar and connect them together.

 

[svsagres]

On a trailer/RV panels are floating... A vehicle is isolated by virtue of being on rubber, not a lightning attractor.

Much like if a powerline falls on the ground when your in a car,you are insulated from it by the tires.

Beware of of internet names/titles. The mean zilch.

Also reread my complete reply above.

If lightning hits your vehicle/RV, a few inches of rubber aren't going to make a lick of difference. It will just blow out your tires, and the plasma will happily conduct through it.

 

[JRH]

If lightning hits your vehicle/RV, a few inches of rubber aren't going to make a lick of difference. It will just blow out your tires, and the plasma will happily conduct through it.

The great tube video I have seen is lightning hitting a car while the car behind it has its camara on 15 ft Away …..at a stoplight , in a rain storm… It hits the top with 4 people inside and exits in about a 3 inch thick bolt of lightning from the lower passenger side of the bottom of the front door . it jumps to ground and is gone…. Very violent event …..it appears to have ran around the skin and exited…no one was hurt inside but the whole cars electric system was fried.
I don’t like lightning.!!!

 

[timselectric]

Lightning is cool to watch.
But, not to feel.