Earthing PV Array? - 22.5kWp System

[fireblade1]

I have read the DTi guidelines and it says earth the array to a rod as main earthing system is PME. I have also spoken to several people who say leave it floating. I'm using an SMA Tri Power TL which obviously has no transformer. Who is right? It is on a 3 storey building so no one can get to it.
Thanks....

 

[SolarCity]

Does the building have lightning protection? What kind of roof is it? It could be a judgement call depending on the circumstances - there are good reasons for bonding the array and good reasons for leaving it floating.

 

[sedgy34]

3 story house i would leave floating as no one will be getting up to touch that, also if there are velux windows it needs earthing

 

[fireblade1]

That is the problem, I can see advantages of doing either. Building has normal tiled roof with no velux or access. Once scaffold is down no one will ever get near the panels. There is no lightning protection on building either, hospital next door has metal roof sheets so that should get hit first by any lightning!! Don't know who else to ask, Dti guidelines are vague and not much help and nowhere is there a technical helpline!!

 

[sedgy34]

if i were doing that building it would be floating, just label at the inverter! installation to be switched off if any maintanance to be carried out on the array.

 

[fireblade1]

That's what I'm leaning towards Sedgy.....

 

[SolarCity]

I would agree - leave it floating.

 

[sedgy34]

That's what I'm leaning towards Sedgy.....

go and get it done matey

 

[BruceB]

Like others, I would leave it floating in the circumstances described.
For technical advice you should phone whoever you are registered with, eg NIC/NAPIT/etc

 

[fireblade1]

I might do that although any time I speak to the NICEIC tech helpline they are equally vague, the regs are often a grey area and open to individual interpretation....

 

[sedgy34]

Just looked up the word Interpretation it means get out clause, not taking responsibility,argue your case but we will send you to jail anyway. Lol

 

[yellowvanman]

Look what Guidance Note 7 suggests: