Earth spike for solar panels in Cape Town

During my PV green card training, we had to design and assemble a full system for the practical part of the course, the solar panel earthing was connected to the main earth, not to an earth spike.
Any thoughts on that ?

I read some time ago that the earthing for panels should not be routed through the house and wired to their own spike… :thinking:
This would be similar to the old lightening arrestors with the arrestor at the highest point on the roof.

That is what I have done and I’m comfortable with that. A direct strike won’t be managed by an earth spike anyway (imho)

That is what more than one installer, and my preferred sparkie, has said/done. Connect all to the same earth with the right-sized earth wire.

Have also read in the past where knowledgeable people argued passionately on HOW to do earthing, solar, and generators, “right”.

My “he knows nothing” takeaway for reading up on it:

  1. Earthing is not an exact science. There is copious knowledge, yes, but the experts don’t always agree 100% with each other 100% of the time.

  2. Earthing for lightning, THAT is a whole new discussion. Think of the highveld, thatch roofs, tall buildings, and their lightning rods … another science to “earth” for lightning.

All I know is that if you have two earth points, and you consider the resistance of the earth between the two, and then you consider a couple tens of thousands of amps flowing across that resistance, then according to ohms law a potential difference is going to arise between those two points. Now you have conveniently connected panels and the rest of the system across this voltage… and you should expect some bad stuff to happen.

Use one and only one earth point, preferably a good one (and generally, the one that comes with your electrical supply is better than whatever you can come up with). If you have more than one, interconnect them.

1 Like

That is what most say yes.

… and then the “fights” starts.

But that is what I’ve done, experts I trussed said, and so it was done.

Depending on the inverter/SCC design, there is a potential path from live to the panel wiring. To be sure to be safe, the panels must be on the same ground too. Multiple ground paths can interfere with RCB/GFCI operation.

IIRC, SANS requirements are quite explicit on this.

If you want lightning protection, put up a separate lightning rod with it’s own earth.

1 Like

yeah… but the existence of the fight doesn’t really add to the right or wrong of the viewpoint. There is a reason we don’t do it :slight_smile:

It’s like those Sunsynk installers always arguing about neutral/earth bonding. Guys, I understand you really really want your view to be true, but that does not make it so :slight_smile:

If I remember correctly an installer told me that for a certain wealthy estate in the North of Gauteng they have an engineer that inspects and signs off all installs before allowing it to connect to their grid. They have a requirement of connecting it to the house’s earth as well as an additional earth spike and interconnecting them.

I like to advertise that I have next to zero electrical knowledge, so I have no idea if this does serve a purpose or not?

South Downs? I’ve heard that they are a little OTT and even tried to pull an annual inspection thing.

Also unsure. I know it pulls them to the same potential, which you definitely want. But there is a risk as well. Let’s say your system is TN-S, which means there is no earth spike on the premise, and that is for the whole street. Now imagine you lose the earth at the transformer… but you have helpfully added an extra interconnected earth at your place. You have just become the earth for the entire street…

Saw this pic and thought … you want to earth your panels for lightning and not have the exact right specialist to advise you … ok.


“On target.”

West Rand, Johannesburg.
Daily Maverick

@plonkster , I “see” what you did there on people wanting to be right … then the fight starts. :rofl:
@fredhen jip, not that estate per se, but yeah, some people have some really interesting “interpretations”. Sometimes it borders on similar debates as with like say “flat earthers”.

Man, I was about 2 seconds away from using that argument and decided against it. That would be a tad too insulting.

This is right. Everything at the same potential.