Faults on new system just installed lastweek

Richchad · Jul 25, 2011

Had 16 Sanyo 250watt HIT panels with Sunnyboy 4000TL inverter installed last week, was working okay for first day but since then getting numerous Grid faults which sometimes throws up Fault-call installer.

Just wondered if it is likely I have a faulty Inverter or would it be something to do with the grid, had power showing zero sometimes without any warnings.

I have informed installer, waiting for electrician to contact me but thought I would see what problems any others have had.

I have Sunny Explorer running but I am afraid most of the readings mean little to me and the help pages aren't great, or maybe it is just me...

PV Martin · Jul 25, 2011

Hi Richard,

1. do you have the installation manual, this will show all the fault codes and the reasons for them?
2. Is the system grid connected or off grid? do you have an unstable grid supply?
3. just a note: the installer has oversized your inverter! this is not an issue it means you have just had to pay a little more where its not required, if the inverter needs changing maybe suggest to your installer a SB3300, and maybe the couple of hundred quid back

PV Martin · Jul 25, 2011

Hi Richard, <br><br>1. do you have the installation manual, this will show all the fault codes and the reasons for them? <br>2. Is the system grid connected or off grid? do you have an unstable grid supply?<br>3. just a note: the installer has oversized your inverter! this is not an issue it means you have just had to pay a little more where its not required, if the inverter needs changing maybe suggest to your installer a SB3300, and maybe the couple of hundred quid back <img src="http://www.electriciansforums.net/images/smilies/smile.gif" border="0" alt="" title="Smile" smilieid="294" class="inlineimg">

Richchad · Jul 25, 2011

Hi Martin, thanks for reply, unfortunately there aren't any fault codes showing, only says Grid disturbance restarting in ** seconds, the red triangle is showing and says fault though.
The system is grid connected and I am not aware of any problems with supply.

Yes I thought the inverter was oversized but as I wanted a TL model from what I have read on here, rightly or wrongly, and the whole package price was very competitive.

Having just looked on Sunny Design about cable runs, I notice that I have a long (20m) AC run from inverter to CU as this looks like only 2.5mm cable wondered if this may be a problem?

PV Martin · Jul 25, 2011

Richchad,

this could be your issue, does the system behave in low light (i.e low output)?

the maximum AC current output of the 4000TL is 22A, BS7671 will tell you that the maximum current carrying capacity of 2.5mm cable is 20A, 4mm will give you 26A. is the cable getting warm when it cuts out?

hopefully your installer should sort this out for you?? Time is Money

Graeme Harrold · Jul 25, 2011

This will be an issue your installer needs to put right and you should have contacted them first. 4000TL Needs a 6mm cable as a minimum. All of the docs can be downloaded from sma.de

Also get your hands on a bluetooth dongle for your computer and download sunnyexplorer from the above site. You will then be able to download the fault history from the inverter (assuming its setup correctly!) Just read you have this.....

Stick with the 4000TL, nothing wrong with it. The 3300 has a slightly lower efficiency for the setup, so your installer got that bit right. Only has a single input and dont think its bluetoothed as standard.

Richchad · Jul 25, 2011

Yes, it seems okay first thing, ie low light but trips when getting brighter, have had over 15 fault events showing today, clears and trips almost immediately again, haven't felt the cable, but will do.

I spoke to my contact with the company and mentioned about the cable, he said the electrician would have installed 4 or 6mm cable, but having looked at it, it sure looks like 2.5mm. He was going to speak to electrician.

Waiting for them to come back to me..........

Richchad · Jul 25, 2011

Just felt the cable, doesn't feel hot but I guess as system hasn't been producing any power for the last 4-5 hours, as it trips after resetting, it hasn't had chance to get warm..
4 or 6mm cable would look much larger that 2.5mm twin & earth wouldn't it?

Hi Graeme, I have the sunny Explorer running on my laptop, waiting for delivery of bluetooth dongle for main home PC, i have seen all the fault events but no fault codes showing, only Grid Faults incoming and out going?

Graeme Harrold · Jul 25, 2011

The size will be stamped on the cable for you to confirm....

PV Martin · Jul 25, 2011

Richchad,

just one more thought what size/rating MCB you feeding through?

Richchad · Jul 25, 2011

Yes, just looked is 2.5 x 2 + 1.5 earth........

Richchad · Jul 25, 2011

PV Martin said:
Richchad,

just one more thought what size/rating MCB you feeding through?

MCB is 32amp which I guess is okay, looks like cable is too small, need 6mm or maybe double up on the 2.5mm twin & earth?

Graeme Harrold · Jul 25, 2011

Deffo need the cable replacing as its 6mm as a MINIMUM for up to 23m

Richchad · Jul 25, 2011

Graeme Harrold said:
Deffo need the cable replacing as its 6mm as a MINIMUM for up to 23m

Thanks for that, will ask for it to be replaced with 6mm, well that has given me great faith in the electrical sub contractor they use....! It seems pretty basic knowledge if you are installing PV systems I would have thought, maybe he was just having an off day.........................

SolarCity · Jul 25, 2011

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.