Array bonding needed?

[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

 

[malcolmsanford]

What amazes me here is the complete lack of electrical knowledge in this

When I did my PV course and this came up, and the tutor said yes you bond back to the MET unless it is PM-E, which it wouldn't be, but I let it pass it is TNC-S in the installation, when it is TNC-S you stake it .................what!!!!

Why ........because the DTI say so....ahhhhhh so if you had a stainless steel boiler flue that could be touched while also touching the frame, that flue is obviously connected to the boiler, pipework is connected back to the MET via main equipotential bonding, and you then bond your frame to an earth stake ................how safe is that when you have 2 potentials within touching distance on the roof ...................blank stares we shall move on

I have yet been given an answer to this, though I know what will happen, if you had a fault within the installation and you were in contact with both potentials..................

Again this is another of these belt and braces decisions by someone, who believes that because it is a TNC-S system, there is a danger of a lost neutral, so it is do it this way and there is less risk, rather than doing what is right and having the competent electrician design and install what is the correct installation.

I have no problem if the DTi want us to bond to a stake if there is a TNC-S system, providing that TNC-S is not on a roof already .................but I would rather them say regarding bonding that the qualified, competent designer should assess each installation as he sees it, and with the information given by the manufacturer, design, install and test an installation suitable for conditions, but then I'm assuming to much perhaps.

 

[rich.250]

I couldn't agree more malc. There doesn't seem to be knowledge behind these statements. Just 'cos it says so' lol.
There a lot of things that bug me with a lot of pv installs at the minute.....
Another is disconnection times.
Feeding into a Rcd way on a cu and then completely destroy the disconnection times for the property or a number of ccts with our even knowing what they are doing is wrong.........

 

[SolarCity]

I couldn't agree more malc. There doesn't seem to be knowledge behind these statements. Just 'cos it says so' lol.

Well I do 'know' that is 'says so', so I suppose there is some knowledge behind it. As soon as you're writing the guidelines that I'm expected to adhere to then I suppose I'll be doing it your way.

There a lot of things that bug me with a lot of pv installs at the minute.....
Another is disconnection times.
Feeding into a Rcd way on a cu and then completely destroy the disconnection times for the property or a number of ccts with our even knowing what they are doing is wrong.........

A pretty general statement. Most of the installers on this forum know that that is bad practice so to I don't really see your point.

 

[rich.250]

Well I do 'know' that is 'says so', so I suppose there is some knowledge behind it. As soon as you're writing the guidelines that I'm expected to adhere to then I suppose I'll be doing it your way.



A pretty general statement. Most of the installers on this forum know that that is bad practice so to I don't really see your point.

I wasn't having a go at anyone in particular.
Yes a lot of people know, just saying that shouldn't it be an important part of the course??
It's not just bad practice. It's dangerous. Say you have a TT with Rcd upfront in the cu. then you had a pv cct in the spare way at the end. Now instead of a 0.2 sec disconnection time. It's probably 5secs depending on equipment used.
You may aswell throw the Rcd in the bin and fit a main switch LOL.
Like I said not pointing fingers just see a lot of it....

 

[rich.250]

Also it is all in bs7671. So follow those guidelines