Grounding, earthing and lightning protection for solar panels

[Isetech]

The first question, what is the purpose of the earth wire connected to the rails system? Lightning protection or to create a path to ground in case of leakage current.

How do you determine if the installation requires lighting protection or just a leakage fault path?

Then we should be asking, do we need to bond each panel in a daisy chain fashion.

Do grounding lugs/plates mounted between the rail and the panel (stainless steel plate with points) create a suitable low resistance path?

The earth spike, it seems to be another topic where people seem to feel that adding an earth spike is the right thing to do, but is it?

[Justloadit]

Adding a metal structure to a roof, automatically creates an area in which is likely to attract lightning.
The addition of the earth wire is to create a path from the metal structure to earth and reduce the damage which may be created by the charged air around the structure if there is no direct path to earth.

Interestingly lightning in the majority of cases goes from earth to the charged clouds, as opposed to the other way round. What creates this is the fast buildup of charge in the air, the earth wire, reduces this charging time thereby reducing the damage to anything thats in the vicinity which could get damaged by the charge up process.

[Isetech]

The Anodised aluminum creates a high resistance, mounted to a wood structure, is it such a smart idea to add a whole lot of bare copper (low resistance) to a solar structure which will then attract lightning.

Mounting it on a metal roof, well that is a whole different story, like any metal roof, add a electrical cable or power source, its becomes a job for people who specialise in lighting protection.

From my experience with lightning, we always loose, no matter what protection we have installed. Be a borehole in a field miles away from civilisation or a house on a hill.

Adding a metal structure to a roof, automatically creates an area in which is likely to attract lightning.
The addition of the earth wire is to create a path from the metal structure to earth and reduce the damage which may be created by the charged air around the structure if there is no direct path to earth.

Interestingly lightning in the majority of cases goes from earth to the charged clouds, as opposed to the other way round. What creates this is the fast buildup of charge in the air, the earth wire, reduces this charging time thereby reducing the damage to anything thats in the vicinity which could get damaged by the charge up process.

[Dylboy]

This PV earthing/bonding what ever frustrates me a lot.

We mount it to wooden beams through tiles, not extraneous to AC current.

The positive and negative are not earthed so earthing is nothing. Albeit I believe some investors may do the earth and negative or positive bond.

Also I spoke with dhen and there one clever degreed oak said anything 100 WP is then we it is considered.

I mean lightning on a direct strike will destroy all.

Induced voltages is different as SPDs can do a bit of that, so panels have surge protection which takes care of that so why we bonding/earthing panels ?

Sure there is static that build up but the panels are class 2 ?? So then people say there are earthing holes and marks... Well maybe that is for the panels in the 100wp range and need LIGHTNING protection... Not surge or bonding.

Bonding is to make metal work at Sam's potential... There is F all DC potential to be made or even AC on panels...

At the moment it is a lot of doing what others do as there is ZERO guidance other than what we can take from out 10142-1 and lighting standards.



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[Justloadit]

This PV earthing/bonding what ever frustrates me a lot.

We mount it to wooden beams through tiles, not extraneous to AC current.

The positive and negative are not earthed so earthing is nothing. Albeit I believe some investors may do the earth and negative or positive bond.

The problem is that wood, glass, and any item that is not a conductor, becomes a dielectric to any 2 pieces of conducting material. In this case, between the aluminium frame, and the silicon PV cell, which in turn is connected to your electrical system via the inverter. Now a dielectric material stores a charge, or can be charged if left alone. So the idea of earthing the frame, is to reduce the potential difference between the PV solar Cell connected to the electrical system and the frame. Should there be a lightning strike, high voltage will flow through the dielectric and the metal parts, causing electrical failure to electronic components. Earthing the frame, ensures that the potential voltage between the metal parts will be small enough to reduce the risk of destroying the electronic components during a lightning strike.

[Isetech]

I doubt a solar panel will survive a lightning strike if it is hit by lightning, I am yet to see anything survive a lightning strike no matter what measures when have taken to prevent it.

[Justloadit]

I doubt a solar panel will survive a lightning strike if it is hit by lightning, I am yet to see anything survive a lightning strike no matter what measures when have taken to prevent it.

Its all about rerouting the path of discharge away from the house.

[Isetech]

Lightning kills animals around the mobile towers (it use to) , some people are installing earth spikes next to their house and connecting the solar panels to that same earth spike.

Its all about rerouting the path of discharge away from the house.

[Justloadit]

Lightning kills animals around the mobile towers (it use to) , some people are installing earth spikes next to their house and connecting the solar panels to that same earth spike.

I would not connect any equipment to the spike, as the role of the spike is to attract the lightning away from its surrounding. Connecting to the spike is inviting surge to what ever is connected to it.

[GCE]

Lightning kills animals around the mobile towers (it use to) , some people are installing earth spikes next to their house and connecting the solar panels to that same earth spike.

The earthing on for instance a tower with an earth mat in the ground will take the ionization that forms in the air down to earth using the earth mat to dissipate the voltage
At the point in time the potential difference in the earth will lift closest to the earth mat and become less further away - Animals legs are 1,5m apart and therefore the potential difference can increase between the legs briefly and sufficiently to electrocute them - The increase in potential difference is dependent on the proximity on the lightening
Is the reason you should shuffle if walking outside in a thunderstorm and the reason why the 2 guys carrying an extension ladder of 5m in a thunderstorm took a big hit - It was not a direct strike but just that they were in close enough proximity of where the lightening happened to hit the ground and the distance between them joined with an aluminum ladder increased potential difference across them .

The potential difference of the ground depending on the size of the strike can be in a conical effect over a distance of 2KM - the attached oic gives an idea

[Isetech]

If I have a TN-S which could potentially become a TN-C-S system earthing arrangement, do I have to install an earth spike and connect it to the busbar which has all the rail, inverter, battery and main grid earth connected ?

If I have a TN-C system earthing arrangement do I have to install an earth spike.

Something to be aware of, we are all from different parts of the country and what applies to me in our part of the country may not apply to others in a group or forum.

[GCE]

If I have a TN-S which could potentially become a TN-C-S system earthing arrangement, do I have to install an earth spike and connect it to the busbar which has all the rail, inverter, battery and main grid earth connected ?

If I have a TN-C system earthing arrangement do I have to install an earth spike.

Something to be aware of, we are all from different parts of the country and what applies to me in our part of the country may not apply to others in a group or forum.

The main reason for the earth spike is in case the utility disconnects supply from the premises that you still have an earth - So I would say yes - All you doing is strengthen your earth point
This is different to the neutral earth story , which is a story by itself

[AndyD]

I would normally only add an earth spike to an installation with a TN C S arrangement that's already PME'd or a TT arrangement otherwise if there's a fault upstream on the supply side you can end up with surprisingly high currents through an earth spike that's been added.

Lightning protection requirements should be decided by a risk assessment that factors in the type of installation and the liklihood of a strike via historical meteorological data amongst other factors. https://arepenergy.co.za/wp-content/...k-Analysis.pdf

[Isetech]

I think this is the confusion, people think they are earthing the panels with a 6 mm wire for lightning protection.

[Justloadit]

I think this is the confusion, people think they are earthing the panels with a 6 mm wire for lightning protection.

Well it will work at least once