Grounding PV Modules / Mounting System

[Bendesa1962]

Hello everyone,

I'm a bit confused about if and how to ground PV Modules / Mounting Frames. Some people say it's not necessary some say it's mandatory.
Some say you don't have to ground the PV Modules because they are class 2. Some say you only have to ground the metal mounting system?

Some say I have to install a Grounf Fault Detector Interrupter (GFDI) Some say that's not necessary because all grid tied inverters these days have
Ground Fault Monitoring.

Can anybody explain to me what is the best thing to do and how to do it?

Many thanks in advance

Kind regards

Johan

[NEOH]

The National Electric Code states, "All non-current carrying metal must be grounded"

There are low-voltage grounding exceptions.
One of the current carrying conductors may or may not be bonded to ground, it depends upon Inverter Design.

[ButchDeal]

Who are these some people?
gfci is required but might be provided by the inverter or mppt, if not must be extrernal.
some areas require afci as well
almost all arrays need to be grounded and the racking.

[SunEagle]

Who are these some people?
gfci is required but might be provided by the inverter or mppt, if not must be extrernal.
some areas require afci as well
almost all arrays need to be grounded and the racking.

Simple rule of thumb when it comes to electrical systems. "All metal objects, support structures, framing or equipment need to be grounded to avoid a voltage potential that can shock or kill"

Another saying by most electrical experienced people I have met. "if it ain't grounded it ain't dead or safe"

[Syberdog]

My understanding is that many of the modern racking components from the big name OEM's have integrated bonding (grounding) provisions.so that when you join the pieces together they from a ground connection.Many other products do not. If they don't then you have to provide grounding. Lookup WEEB clips and grounding jumpers if you need them. Even with self-bonding components you may still have to ground each row of PV modules to the rack frame then to a rebar driven into the ground or use another acceptable method. I am not an electrician so consult one before taking my advice.

[Murby]

I am using the IronRidge ground mounting system.. a lot of youtube videos show a continuous grounding wire running at the top of the mount that connects all of the XR rails together.. When I called up and talked to IronRidge, they said it wasn't required and that you only need to ground one of them.. the rest of the system grounds itself to that rail because its all metal and bolted together.

When my electrical inspector looked at my system, he specifically looked at the earth ground and said it was fine. I only grounded one rail to an 8ft ground rod.

[sensij]

When my electrical inspector looked at my system, he specifically looked at the earth ground and said it was fine. I only grounded one rail to an 8ft ground rod.

The IronRidge Ground Mount manual clearly agrees with this approach, see page 7. However, if the IronRidge rails were mounted to a structure that had not been tested for grounding (home-built or otherwise), copper tying one rail from each row together could be required.

[tyab]

Correct sensij&murby. Interesting side note - I was emailing IronRidge tech support about NFPA 780 testing (they have not done any UL 96/A listing), and ended up having a phone conversation with one of the techs and this subject came up and they said have run into AHJ's that not only want all the rails bonded but in addition want each rail bonded to the 3" pipe.

So I asked my AHJ (sure helped I could pick his brain after early morning swimming) and he told me that he would accept a single rail bonded if the IronRidge grounding midclamp was properly used but he would rather see (but not required) all the rails bonded. In addition he wants to see a single bond to one of the 3" pipes. For the single pipe bond he said the there was only pressure of the rail mounting adapter to the pipe and with the mounting adapters being anodized it brings into question how good of a bond that will be over the life of the system. Sounds reasonable. I asked him about bonding all the rails and for him its an issue of proper installation of the mid clamps and correct torque values. In his experience - owner installs don't torque them correctly - so he would check a couple easy to access and if they were out of spec he would require all the rails bonded. For those contractors that he knows do a good job, he accepts it as is by IronRidge BUT does make them do a single bond to one of the 3" pipes.

The church where I run scouts out of put in a large system a couple of years ago (IronRidge - 160 panels) and sure enough on the three mounts you can see where the contractor drilled and use a tap ground on one of the 3" pipes and it bonds to one of the rails. I guess a listed 3" pipe clamp was not on the truck

So I just bonded all the rails (and did a bond to both of the horizontal pipes) as to not have any issues. For me on my four mounts, it was about an extra $180 in WEEB lugs and 3" pipe ground clamps.

[Mike90250]

.........to a rebar driven into the ground or use another acceptable method. I am not an electrician so consult one before taking my advice.

Rebar is NOT a qualified ground rod.

Stores sell a 10' copper plated steel rod, designed and certified as a ground rod.

I am not an electrician so consult one before taking my advice.

Actually, that's good advice, consult a real person in your code area, to advise you.