Solar earthing question

[alan-c]

I am putting together a solar powered mains supply in my garage. I have a 260W panel feeding a 24V 110Ah battery via an MPPT controller feeding a 1kW inverter. The instructions for the inverter say that it should be earthed and the solar panel frame has an earthing point. I am planning to connect the panel earth point to the inverter external earth point and from there to a 13A plug plugged into the real (grid) supply to make the earth connection, not using the live and neutral. Does this make sense?

 

[Deleted member 26818]

It makes sense, but I would not do it if I were you.
I would question why you need to earth the solar panel and the inverter earthing should be mechanically robust, not something that can be easily disconnected.

 

[alan-c]

I presume the solar panel frame needs to be earthed to protect against lightning strike, which would otherwise travel down the power cable to the battery and inverter. The inverter is not earthed, it is not connected to the mains.

 

[Pete999]

I am putting together a solar powered mains supply in my garage. I have a 260W panel feeding a 24V 110Ah battery via an MPPT controller feeding a 1kW inverter. The instructions for the inverter say that it should be earthed and the solar panel frame has an earthing point. I am planning to connect the panel earth point to the inverter external earth point and from there to a 13A plug plugged into the real (grid) supply to make the earth connection, not using the live and neutral. Does this make sense?

I am putting together a solar powered mains supply in my garage. I have a 260W panel feeding a 24V 110Ah battery via an MPPT controller feeding a 1kW inverter. The instructions for the inverter say that it should be earthed and the solar panel frame has an earthing point. I am planning to connect the panel earth point to the inverter external earth point and from there to a 13A plug plugged into the real (grid) supply to make the earth connection, not using the live and neutral. Does this make sense?

No not really, sorry

 

[Deleted member 26818]

I’m not an expert on lightning protection systems.
However I doubt that having the thousands of volts from a lightning strike flowing through the socket circuit CPC is a good idea.
If you do not intend connecting the inverter to the mains, then I would be very wary about connecting the earth to the Mains earthing.
Any earth fault current associated with the inverter and whatever it’s supplying will also appear on the Main earthing and whatever is connected to it.
Conversely any fault current on the Main earthing will then appear on the inverter etc.
An RCD on one system, will not detect fault current from the other system.

If you really want to earth the panels, install a separate Earth Rod and use quite a large conductor.
The CPC of whatever is connected to the inverter will have to be connected to the inverter earth connection.
You may have to provide another earth rod for the inverter?

 

[alan-c]

Thanks for your answers. I guess my question should now be: should I connect all the components mentioned to an earth rod in the ground or would it be best to leave them all isolated?

 

[Obbit]

The inverter casing will be connected to earth internally anyway.
The PV modules can be earthed to an earth rod (not the main intake earth as the DNO don't like DC earth faults on their AC network). The earth isn't to protect against lightning strike, it'll be hopelessly small for the job.
PV systems are rarely earthed but there is a valid arguement on both sides about whether to earth or not.

 

[alan-c]

The inverter casing isn't connected to anything at all. Maybe it is supposed to be earthed to prevent EMI either in or out. I think I will just leave all metalwork isolated and disconnected and see what happens.

 

[Deleted member 26818]

It may be that the inverter needs to be earthed so it can detect if there’s an earth fault on whatever it’s supplying?