Hi Guys.

Quick question please.

1) As far as I understand, SANS 10142 wants your solar panels earthed, and bonded to it's own dedicated earth spike (PE).  The reasoning behind this is that IF lightning strikes the panels, the path to earth does not touch the rest of the electrical installation (your PV panels are essentially isolated, provided your fuses can withstand a lightning strike, of course).

2) When you add surge protection to the PV however... Does the earth for the surge protection go to the PE (panels' ground spike), or can the earth go to the electrical installation?  As I see it, the surge protector needs to be earthed to the same spike as the solar panels, in order to keep the isolation, right?

Reasoning for asking is that I have a fairly longish cable run for a upcoming monster installation.  I am trying to avoid running copper, as it would be significantly cheaper to just sink an earth spike... But if I have to run copper for the surge protectors in any case.... Well... Hoes I guess?

 

Edited April 28, 20233 yr by Chris Knipe

6 hours ago, Chris Knipe said:

Hi Guys.

Quick question please.

1) As far as I understand, SANS 10142 wants your solar panels earthed, and bonded to it's own dedicated earth spike (PE).  The reasoning behind this is that IF lightning strikes the panels, the path to earth does not touch the rest of the electrical installation (your PV panels are essentially isolated, provided your fuses can withstand a lightning strike, of course).

2) When you add surge protection to the PV however... Does the earth for the surge protection go to the PE (panels' ground spike), or can the earth go to the electrical installation?  As I see it, the surge protector needs to be earthed to the same spike as the solar panels, in order to keep the isolation, right?

Reasoning for asking is that I have a fairly longish cable run for a upcoming monster installation.  I am trying to avoid running copper, as it would be significantly cheaper to just sink an earth spike... But if I have to run copper for the surge protectors in any case.... Well... Hoes I guess?

 

Per (1)  there is always a debate going on, but my opinion is stay with SANS. There is the charismatic Mike Holt that preaches otherwise, but I for one cannot always follow and understand him. 

(2) you are not trying to protect the panel outputs per se, instead you need to protect the inverter. Thats why the surge protection is in close proximity to the inverter pv ports, and for this reason you need to use equipment earth, for which the inverter itself is referenced to, by virtue of its grounded neutral.  And consider that the mainstream inverters is transformerless, which means, inter alais, that neatral ground is switched onto the pv outputs at alternative mains cycles. 

Good luck with your rollout and may it serve you in your best interest regarding function and safety. 

Edited April 29, 20233 yr by BritishRacingGreen

6 hours ago, Chris Knipe said:

The reasoning behind this is that IF lightning strikes the panels, the path to earth does not touch the rest of the electrical installation

If lightning strikes your house say goodbye to your solar system. I think it is more a case of dealing with touch and step potentials for strikes in the vicinity.