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wstevew

I have a SMA 4000TL and I'm not sure if the arrays are bonded (I can see no evidence that it is).

Is this dangerous and does it break any rules or regulations?

There is no access to the roof. Will the TV aerial will be earthed through the cable
And if so would bonding have to be to the CU.

I am getting error 601 DC current detected in AC approximately twice a week outside of feed in time.
 
I;ve read a few threads on this and am keen to know as well as I have a 3600TL. From what I have read the concensus seems to be the arrays should be bonded to a ground spike (mine dosen't appear to be).

Can it be earthed in another manner?

Regulations aside, I would also like to know is how risky to the equipment and people working on the roof would it be if it wasn't earthed?
 
This is a very difficult one and grey at the moment, the DTI have got a new decision tree of which I have only seen the draft which says that no earth bonding is required on a TL inverter. There are obviously conditions to this, i.e. If you have a velux next to the array an earth bond must be in place, and all the other usual stipulations.

In the standard BS7671 this is not the case and as far as I am aware there is a bit of nonsense going on at the moment, where it says the array should be earthed, however by doing this you are introducing circuit which is a bit contradictory for Class II products (forgetting special installations at the moment).

This is all a can of worms at the moment, some manufacturers stipulate an earth on the DC side is not required and therefore if you were to follow the regulations it would say manufacturer guidelines supersedes those of BS7671:2008.

The question then is how is it earthed, my opinion is if it is earthed it increases lightning strike potential and would therefore have to come under lighting protection rulings. If the array or any of its exposed conductive parts can come in hands reach then an earth is required.

If a guy is on the roof it is less likely that he would be the earth path, however if an earth has been there for years and lost continuety in part of the installation that guy could become the brige between both conductors (owch, this is obviously speculation as to if, why and how ten years down the line).
 
I had my annual MCS assement today, NICEIC guy said NOT to earth array, even though i had on my inspection site, only when velux etc as stated above. He showed me the DTI decision tree and it was pretty clear that earthing is not required, he says that over 95% of installs he sees now are not earthed. Saves me some cable and hassle anyway.
 
I had my annual MCS assement today, NICEIC guy said NOT to earth array, even though i had on my inspection site, only when velux etc as stated above. He showed me the DTI decision tree and it was pretty clear that earthing is not required, he says that over 95% of installs he sees now are not earthed. Saves me some cable and hassle anyway.


Was it my draft, I am sure my MCS inspector stole it
 
Don't Earth the array!!! Even on TL's This is what Ive been told by the technical manger at ELECSA
 
Well lads it is either one or the other ................earthing or bonding it can't be both.

As the array is classed as a class II installation then I doubt it is earthing, so I guess we should be calling it bonding.

I'm still waiting to see if your standing inside your bedroom window clutching onto your metal radiator for support which is bonded via the pipework back to the main bonding in a TNC-S and you happen to touch your array frame which the DTI recommends your stake, and there is a fault inside the installation, what happens to you as there will be defiantly a little potential difference
 
Just because some inspectors are allowing installations without bonding doesn't mean that you must not bond, Dti guide/mcs is the minimum requirement.

Tom
 
^ Agreed.

The bond/not-bond debate has been going on for ages and I see the argument for both. However, Dti guide is pretty conclusive so that is what we do. Most of our installs use TL inverters and most of our arrays are bonded, often to an earth rod.
 
I had my annual MCS assement today, NICEIC guy said NOT to earth array, even though i had on my inspection site, only when velux etc as stated above. He showed me the DTI decision tree and it was pretty clear that earthing is not required, he says that over 95% of installs he sees now are not earthed. Saves me some cable and hassle anyway.

same from ELECSA 2 weeks ago. Said DTI guide was open to missinterpretation
 
Is there some confusion going on here between earthing the array and bonding the array frame? Two totally separate issues. The latter is covered by the decision tree in the DTI guide and categorically states that if the inverter is transformerless, the array frame must be bonded. Try as I might, I cannot misinterpret the decision tree - it's pretty straightforward.
 
I have seen a copy of the decision tree for "The Guide to the installation of PV systems 3rd Edition" however since I beleive it is draft it cannot be taken as true.
 
Well I suppose NICEIC have their own version of the DTI guide, much like they do with the regs. :dizzy2:
 
My assessor said earthing only needed in areas of higher possible incidence of lightning strikes. I argues this isn't what the earthing was for but he was adamant.
TBH I'm not sure he understoof the rsationale behind earthing the array which I have tended to do on TL inverters as per the DTi tree. My understanding though is SMA inverters don't need it as SMA certify their inverters, although not galvanically isolated, cannot leak accross the AC DC divide due to inbuilt protection.
 
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I spoke to Power One and they said that I must bond the array frame, so have done ever since with all TL inverters


I spoke to Power one and they said i SHOULDENT bond the array unless roof has velux etc, different guy different interprentation, I certainly wouldent take the word of anyone working for one of the kit manufacturers either way though.
 

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