Array bonding needed?

[moggy1968]

So, in response to the OP, the jury is out. As there is such a division of opinion I would say it's down to the individual installer and personally I wouldn't say it leaves your installation potentially unsafe.

 

[SolarCity]

Moggy, the purpose of bonding the array is nothing to do with the leakage of DC current onto the AC side of the installation - and I'm absolutely baffled by your assessor's suggestion that bonding is for lightning protection.

 

[moggy1968]

earthing, not bonding
I was a bit baffled as well.
my understanding is it's to provide earthing should the array become live due to leakage currents crossing onto the DC side, sorry, have ammended my previous

 

[JulianC]

My reasoning for bonding the array frame with a transformerless inverter is simple: the DTI guide says I should and MIS3002 says I should do what the DTI guide tells me to. So, whether I agree with it or not, I do it. I couldn't care less what a scheme assessor or some monkey employed by an inverter manufacturer says because MIS3002 doesn't say I have to. Do you really think your scheme assessor knows more about PV installations than you do?

 

[moggy1968]

it's a fair point!

 

[SolarCity]

earthing, not bonding
I was a bit baffled as well.
my understanding is it's to provide earthing should the array become live due to leakage currents crossing onto the DC side, sorry, have ammended my previous

But surely the Dti guide is referring to bonding?

The framework and panels should all be class II so earthing doesn't come into it.

 

[moggy1968]

Are you bonding areas of equal potential though, or are you providing a path to earth for rogue current?
I think probably this has all been debated ad infinitum elsewhere, mostly by people far more knowledgable than me. so I can't see anything to be gained by going over it again TBH so I'll leave it there.

 

[SolarCity]

Are you bonding areas of equal potential though, or are you providing a path to earth for rogue current?

I'd say a path to earth due to the topography of the inverter. I see this more as bonding rather than earthing as we are limiting touch voltage rather than limiting fault time.

I think probably this has all been debated ad infinitum elsewhere, mostly by people far more knowledgable than me. so I can't see anything to be gained by going over it again TBH so I'll leave it there.

Likewise and agreed!

 

[wstevew]

I kind of thought I may get a 50/50 response.

Here's what I got.from SMA. (Now do I believe the SMA monkey, I have 2 arrays maybe bond one of them LOL. Kidding)


"The event 601 is as you describe, DC Grid feed in.

This can be caused by a number of things, certainly in the first instance, I would suggest that you check with your installers to check that your array has been correctly bonded to earth, they should be able to sourse the correct bonding information from the manufacturer of the array frame.

The 10223 event number ist he inverter saying that it cannot find a power reducer box, so the time interval for checking has expired. The power reducer box is not used in the UK, so this is of no concern for us here.

Best Regards,

Darren.

Von: [email protected]"

 

[wstevew]

Thanks for all your responses.

Hypothetical question.

If one of your customers came to you with the above error and that response from SMA what would you do?

 

[Noshocks]

Thanks for all your responses.

Hypothetical question.

If one of your customers came to you with the above error and that response from SMA what would you do?

Sorry me not speak english, then run!

 

[moggy1968]

is it correctly set up for the UK?
I can't see DC grid feed in being anything to do with bonding/earthing!

 

[wstevew]

It says G83 on startup. Supposedly it means DC current detected on ac side.

 

[moggy1968]

yes, but I can't see that being associated with bonding.
According to my assessor who took me to task about this, G83 doesn't necessarilly mean it's UK set. How long does it take to power up, should be 3 minutes.

 

[BruceB]

That's interesting. Some other tiny countries might jump on our bandwagon and use G83, but otherwise I would have said it is very much a UK standard.

3 minutes is after a grid failure. When first starting up from cold the 3 minutes limit does not apply.

 

[moggy1968]

If you switch off and switch back on it should take 3 minutes

 

[wstevew]

Yes I did reset once with the ac isolator and it took what seemed like ages before restarting feed in.

 

[Glen Powell]

Reset procedure should be AC off DC off , DC on AC on,

putting AC on first can really delay the start up on some inverters (IMO)

 

[wstevew]

Is that not the same as ac off and then on?

 

[rich.250]

Don't bond the array to the MET!! Your all electricians here and there is no need to bond anything that is not a parallel path.
Test it to see!!
All that will be achieved by bonding it, is creating a form of lightning conductor!!......
Supplementary bonding may be required, again testing can prove this. Or if manufacturers state sup. bonding these must be followed.
But definitely do not earth it to the ground!! You will introduce a difference in potential that could and will be potentially life threatening.
It's not rocket science just basic electrical theory. It's all in bs7671