Lightning 6.7.7 and surge protection 6.7.6

[Isetech]

Class 1 - lightning protection

Calls 11 - Surge protection

Something I dont believe many people understand when doing a test report where there are PV panels on the roof and surge protection in the DB.

You need to understand the difference between lightning protection and surge protection, before you start scribbling and ticking the test report.

Once again feel free to add your comments about this topic, I am not lightning protection specialist and find it rather difficult to find people who know what they are talking about.

The panels on the roof you need to ask yourself the question, do I need to earth the panels and rails and by earthing them will lightning protection be required.

Note!!

"Whenever a building has external lightning protection such as a mast, or conductors on the building, Class 1 lightning current arresters are required."

Once you install a set of PV panels on the roof and link them together with an earth wire and take it to ground, then things get more interesting.

Do you install class I or class II surge protection in the combiner box?

If you use steel cable tray or steel piping between the panels and the combiner box do you run a bare copper wire and install an earth spike?

Do you connect this wire to the grid earthing system, knowing if there any transient spikes, there is a good chance your system is going to the lala land.

Do the PV green card training course go into detail about all this important stuff?

[Isetech]

Something to take note of when collecting the site data, the surge protection voltage. A couple of years ago, it wasn't a big deal because most domestic installation the panels would only produce under 200 VDC, the newer installations the VOC could be higher than 500 VDC and some of the surge protection is only rated at 400 VDC.

[Dylboy]

I spent a long time with DHEN at the solar show and spoke with a very bright chap...

In essence, lightning goes with lightning, i.e 16mm, masts, down conductors and generally only when it's around 100KWP do they look more into lighting.

When people bond or earth 16 panels it is for Surge protection... Do nearby lighting strikes...

Interesting if the roof is isolated from earth then running an earth spike or even an earth cable to the main earth introduces things now and not always in a good way...

So having type 11 is good none the less but running binding cables to all the panels and to earth via separate spike or Eskom Earth then it can introduce equilibrium issues and not be needed....

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[Dylboy]

Also want to add I'm still learning this topic a bunch too.

Also the solar PV schools do not teach this... They don't even teach them to seperate AC and DC in wireways...



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