Invertor Error - FE Not Connected

[lovelldr]

Hi guys.

So, we've had solar panels installed on the roof for about 3 years now, and just recently, had an issue where the Invertor in the loft was bleeping. Went up to investigate, and it'd stopped...

So, a few days later, heard the bleeping again, went up to check, and could see the Invertor had a flashing screen between red and blue backlight. Looking on the screen, it said FE Not Connected.

The Invertor we have is a StecaGrid 3000. Found a copy of the manual here:

http://www.steca.com/frontend/stand...x0x0x0x0_StecaGrid_coolcept_coolcept_x_EN.pdf

Looking at the manual, the error means:

The protective earth is not connected. For safety reasons the inverter is not allowed to inject into the grid.

Notify your installer

Now, the trouble is, our installer is no longer available, as the company ceased trading... So, what does this mean. If the protective earth is not connected, why would it only become disconnected intermittently... What should we do to try and resolve the issue?

Any ideas please guys?

Cheers

 

[Delboyalpha]

Hi- i've seen this a couple of times during solar call outs... both were very simple poor connections of the earth conductor.
If you're happy to, turn of the inverter AC side (red isolator) after a couple of seconds, turn off the DC isolator ( black isolator). Next go to consumer unit and turn off the circuit marked as solar or PV. Circuit is isolated and safe.
Physically check all earth terminals starting at the inverter connection, then AC isolator, then generation meter, then lockable isolator @ consumer unit, then finally the consumer unit. The loose connection should present itself when it comes out in your hand!
However.... if you're really unlucky its a 'earth leak' fault on the DC side. I have also seen this read as PE fault, earth current fault or 'grounding fault' on inverter. Usually caused by bad MC4 connection on roof- and you really don't want that!
Good luck
Del boy (Alpha Eco Systems)

 

[lovelldr]

Hi Delboy.

Thanks for the reply... I'm quite happy to try this, but, not sure where exactly I should be looking to check the earth terminals?! Would it be a case of opening up the inverter box, and the isolators? Hopefully it is something simple like that ...

 

[Delboyalpha]

Hi, on inverter only remove terminal cover of you model has that, I've never installed Stecca myself but have seem them insuitu.
Open up the isolator/generation meter cover/inverter connections and give the earth cable a gentle pull. If it comes away in your hand... hey presto! That's what we are lookin for. Re connect it replace covers and switch inverter back on, DC first on inverter (inverter takes its power from DC side usually) then AC side. The fault should have gone.
If after checking all earth terminals and no loose found, restart the inverter and check if any fault message appears. If fault persists, try the inverter manufacturer as there is a chance it is an inverter fault- stecca have a five year manufacture warranty, so makes no difference if installer is trading or not if the fault is within the inverter itself. Contact details should be in the system paperwork, if not good ol google should get you a number to call. Call them with the fault as displayed and ask for a replacement! You will be surprised how often a company will replace an inverter once you have checked the basics.
You will have to pay someone MCS accredited to do the changeover, typically £100, but that's a lot cheaper than £600-1000 for an inverter.
Del Boy

 

[whinmoor]

Have you noticed any relationship between the weather and this fault? Does it happen when/after it rains? If so, it could be that water is getting into a faulty connector on the roof.

 

[lovelldr]

Hi guys. Thanks for replies to this.

Went in to the loft on Saturday to have a look... The earth connections all seem to be fine from what I could see...

There does seem to be some kind of pattern... It appears to do it mostly first thing in the morning, and last thing at night ... So, my guess is it could be something to do with the panels themselves? As this appears to be when it first starts to get sunny, and when it stops being sunny (i.e. starts generating and stops generating).

As a test, I removed the earth in the AC side, turned all back on, and it came up with the error straight away. Turned all off again. Replaced the earth, and it was fine. Until it came to dusk that evening, and it started beeping again...

What could this show? Any ideas?

 

[Wilko]

Only thing that occurs to me - it's the times when temp is changing (which can cause small movements in the structure etc) so it may support the loose connection theory.

 

[lovelldr]

One other thing that strike me that could be the problem...

We have two AC isolators. One by the inverter in the loft, and one by the solar panel meter reader. Just checked through all the isolators again, and here's some pictures of them.

First, the Isolator in the loft:

As you can see, here, there is an earth that goes from the isolator, both to the invertor, and down the cable...

However, the cable runs across the loft, down the outside of the house, and then in to the garage, where it goes in to the isolator in the garage, as shown below:

As you can see in this isolator, there is no earth connected. There is then trunking (the one you can underneath the isolator), that I am guessing goes in to the meter, and then the trunking goes around the garage, in to the consumer unit in the main house...

Now, I'm guessing that the problem is, that the installers didn't actually properly earth the system, and that's why the invertor is complaining. Is this correct?

If this is correct, how come, only now, the system has started to complain? Another thing that I'm guessing (but still could be wrong about), is that the earth that comes from the isolator in the loft by the invertor, is actually earthed some other way, and not through the main house earthing loop (i.e. could they have just connected the earth cable to something metal thinking that would be enough). And then with the age of the system, this "earth" just isn't good enough?

Do you think I should try and contact a solar installation company to resolve this mystery?

Cheers

 

[Gavin A]

you'd need to take the lid of the trunking, the earth is probably linked out in the trunking.

Dare I suggest that you might need to get an electrician round to test this out and confirm if it's an inverter fault or a wiring fault?

Chances are that it's an inverter fault, in which case it will be a warranty swap out, but if they find there's actually nothing wrong with the inverter then you'd get charged for it.

 

[whinmoor]

If you state where you are located, you might find someone on this forum is based nearby and able to help. It says "UK" under your name but that's a bit vague.

 

[Wilko]

I'd like to have seen the cpc taken in there as it is a separate isolator. But that won't be the cause of this problem now. I'm with Gav and WM, it's time to get some on site help.

You probably know this, so just a reminder - opening those boxes exposes you to risk of electric shock ...