Faults on new system just installed lastweek

[Richchad]

2.5mm twin and earth and 32a breaker on a SB4000TL? That doesn't fill me with confidence. Have they filled it out as such on the test sheets?

Regarding the SB4000TL, the installer got this right. A perfect inverter for the size system you have. Using the SB3300 would result in yield loss I would suggest.

Haven't seen any test sheets as yet, guess they will come from installer as electrician is a subby, have done registration but have been told other paperwork to follow, so maybe will be in that...

Perhaps now I know why the quote was a "good" price.......

 

[SolarCity]

To be fair to the installer, he may have had his hands burnt by the electrician. It is ultimately the installers responsibility that you get a job but we've all employed someone that has been less than up to the task. Let the installer put it right and take it from there.

This may not solve the problem. You may be having problems with grid voltage. Are you in a rural area? Is your house supplied from an overhead main?

 

[Richchad]

To be fair to the installer, he may have had his hands burnt by the electrician. It is ultimately the installers responsibility that you get a job but we've all employed someone that has been less than up to the task. Let the installer put it right and take it from there.

This may not solve the problem. You may be having problems with grid voltage. Are you in a rural area? Is your house supplied from an overhead main?

Suppose it is fairly rural, east of Oxford, not overhead, 15 year old houses on a small estate, haven't noticed any fluctuations in lights here, if that means anything....

Will see once cable is replaced I guess..

BTW working again now, now sun is lower and power reduced, was out since about 11am until now...

 

[SolarCity]

BTW working again now, now sun is lower and power reduced, was out since about 11am until now...

Definitely sounds like voltage related to me but this may be due to the undersized cable. You'll not notice minor voltage fluctuations and they certainly won't visibly affect the lights.

 

[Richchad]

Definitely sounds like voltage related to me but this may be due to the undersized cable. You'll not notice minor voltage fluctuations and they certainly won't visibly affect the lights.

Yes, the cable/voltage does seem to make sense, as working now at about 2-2.5kw.

Grid voltage is showing at around 248 ish, how much has it got to fluctuate by to give a problem?

 

[SolarCity]

If I remember correctly, the display on the inverter will show what voltage the inverter is producing rather than what the grid voltage is. The grid voltage will be slightly lower than this. If the grid voltage goes over 253v then the inverter will cut out.

 

[Richchad]

If I remember correctly, the display on the inverter will show what voltage the inverter is producing rather than what the grid voltage is. The grid voltage will be slightly lower than this. If the grid voltage goes over 253v then the inverter will cut out.

I took the ac voltage from the Spot Values on AC side on sunny Explorer, haven't seen it change much other than a few decimal points up or down but then haven't been watching it continuously...

Thanks for all your input everyone, has been most helpful, still waiting to hear when electrician will be coming back, will update with results, which hopefully will be good news..!

 

[edexlab]

I currently have this same problem with a 4000Tl and sanyo 245 panels nothing wrong with the setup I've fitted lots of these.
cable run is approx 3mtrs and (6.0mm cable, array earth rod has good reading 45 ohms and Ze was 0.30 ohms on TNC/S ) from supply cutout but the property is quite rural and at the end of the line neighbouring a couple of farms
while commissioning Grid disturbance came up on screen and so put the meter on and noticed the voltage fluctuating a fair bit, anyway I'll have to wait and see what Dno will/or can do about it , I'm not sure adjusting the Taps will be enough to sort it.

 

[Richchad]

I currently have this same problem with a 4000Tl and sanyo 245 panels nothing wrong with the setup I've fitted lots of these.
cable run is approx 3mtrs and (6.0mm cable, array earth rod has good reading 45 ohms and Ze was 0.30 ohms on TNC/S ) from supply cutout but the property is quite rural and at the end of the line neighbouring a couple of farms
while commissioning Grid disturbance came up on screen and so put the meter on and noticed the voltage fluctuating a fair bit, anyway I'll have to wait and see what Dno will/or can do about it , I'm not sure adjusting the Taps will be enough to sort it.

I haven't seen any array earthing rod fitted to my installation, just twin & earth runs from inverter to CU, when is it applicable, house was built 15 years ago if that gives any clues?

 

[SolarCity]

You're probably on a TNCS system which means that the installer probably should have installed an earth rod. This WON'T be the reason why your system is playing up and your installer could probably give a pretty good reason why he hasn't used one. The earth rod/no earth rod debate is still going on and I wouldn't criticise the installer for not installing one.

 

[solarsystems]

just a thought..... how many stings has he brought from the array?

 

[Richchad]

You're probably on a TNCS system which means that the installer probably should have installed an earth rod. This WON'T be the reason why your system is playing up and your installer could probably give a pretty good reason why he hasn't used one. The earth rod/no earth rod debate is still going on and I wouldn't criticise the installer for not installing one.

Thanks for that, glad it isn't something else I have to worry about..

 

[Richchad]

just a thought..... how many stings has he brought from the array?

I believe it is 2 strings, not sure how I can tell, there is two sets of cables coming through the roof to the inverter, however I notice that on the inverter when the display graphic automatically switches between strings nothing shows on one of them..?

Can I tell from Sunny Explorer and what difference would it make?

 

[dansk]

that sounds reverse polarity on one string, and would explain it cutting out etc. I don't have experience of sma inverters so don't take my advise as gospal.

 

[Richchad]

that sounds reverse polarity on one string, and would explain it cutting out etc. I don't have experience of sma inverters so don't take my advise as gospal.

If that was the case, wouldn't it show a permanent fault, had 3.7kw yesterday before it cut out... but then what do I know.........