Transformer vs transformerless inverters

[SolarCity]

Daytona, which ones have a higher efficiency than transformerless ones?

 

[brian wright22]

Originally Posted by brian wright22
The main reason I require my system PV array mounting frame earthed is because less than 2 feet away from the edge of the array mountings is my TV & FM aerial mounting pole which is definately bonded at house earth via my HiFi & TV system.
So I suppose you could say its within the Equipotential Zone.

I have received a mail from the IEL stating that the DTI are in the process of changing their recommendations regarding this earthing requirement. As I see it though, until the new DTI and BS guide lines are issued then the present DTI recommendations should prevail.

This is the latest response I have received from Homesun regarding my request to have an earth connected to my PV array mounting frame.

Dear Mr Wright,

I am sorry that I have not come back to you earlier. However I have been speaking with Ben and other technical engineers within Eaga about the earthing of your mounting frame.

Our first concern with any installation is the safety and security of the homeowners, as such I’m sure you can appreciate that we do not make these decisions lightly. After extensive conversations with Eaga’s Technical Engineers for quite some time now, It is their considered and professional view that your array mounting frame does not require earthing and the installation of the Solar PV system meets all relevant regulations.

Once again I’m sorry that it has taken us a long time to get to this stage.

Kind Regards,

Krish Patel
HomeSun Customer Team
0844 824 0000.

 

[gregs2277]

This seams a bit amasing to me as i have come accross this chat as i was just googling an interest b4 i install on my own house. i have been installing i Australia for the last 3 years and the rules over this time would change inbetween installs! but as for the earthing of TL systems it is mandetory here and has been for some time. as we have alto of colour bond roofing here (corrigated iron) it would be STUPID to not earth the array to the MEN system we have here. no seperate earth stakes here if it is not earthed it will not be signed off by the electrical inspector as we have to for all perscribed works here and therefor not connected to the grid!

 

[valet]

Yes the same in Caribbean. My installer connected ground/earth cable to all railings panels sitting on and connected to separatly instaled ground spike. As per local requirements. My inverter Fonius IG 30 plus and has transformer. Do I need to change any settings on my inverter or have to leave as it is. In inverter settings it option grounded and un grounded m. Panels not connected to the spike only rails they siting on. Just dont want to play around with inverter setings as it works ok. Can I just leave railings conected to the earth spike, no danger to be on the roof and cleaning panels if needed? Thanx

 

[Worcester]

You should be fine leaving the settings as they are.

It is also common to earth the rails, the panels should be connected well enough to the rails through the panel clamps.

The inverter setting re grounding relate to thin film PV where usually either the +ve or -ve output from the panels is grounded.

 

[SolarCity]

Valet - If I remember correctly you have a metal roof? If you do then your system was probably bonded to it as there would be a high chance that it would be measured as an extraneous metal part.

 

[grantr37]

I'm led to understand that the market is moving towards TL inverters?

As I understand it they are slightly more efficient and are less fussy about string confirguration, just wanting as big a string as possible?

TL inverters are silent and Transformers get noisy as time goes by and a transformer inverter may well be a noisy beast in 10 years time?

TL inverters are firmware upgradable and as such new firmware in the future may well make them yet more efficient?

TL inverters have better comms built in making it easier to connect portable displays and internet connections?

If you've been wrestling with the TL possibilities what are you thinking?

I wouldn't think a software update would make a unit any more efficient, the program loaded onto the controller ROM will do what the box is designed for when it leaves the factory...updates on things like this are just to keep a foot in the door....

 

[valet]

Thanx guys for you answer! ! Yes you are right Solar city good memory, metal roof.

New project: Old earth cable coming out from the ground. That earth was bonded to old pool pump. Now Im going to install new more efficient pump. How do I test old gtound spike/cable for good resistance at least 25oms. I know I should have ground resistance tester for that. But iam not going to spend 1k for sake one test. Some one suggested to put new one. But its deep concrete everywhere.

Thanx guys. Hope business picking up for tou.