(as in The Magic Wagon! Longstanding nickname to do with non-eco petrol headedness back in the day... )
intrigued now (JC fan here)
Running 3kw panels with this inverter and no batteries (as yet). Not every morning but 6 times in last two months (since install), its tripped the MCB. It seems to be just about when the panels are just starting to generate, so a few watts, hardly the 16A needed to trip.
Swapped out the MCB and checked/tightened all the wiring and put a 20A MCB in - tripped again...
I believe that the Solax does some "self-testing" when it wakes up/first receives power, so is the result of a faulty unit or is it in the wiring/MCB or...? Solutions?
My 3kW Solis inverter is connected with a 32A MCB. Maybe 20A is too low for yours?
First, I'm not a sparky, but there are warning bells ringing in my head...
1) Is this a DIY install? I am guessing not as you refer to a quote and are saying '
how new I am to this'. We obviously don't know your level of expertise, but the first thought is have you had the installers back to rectify this issue?
2) If they have looked at it, but are unable to fix it, then I suggest you get a sparky in, preferably one with solar experience. I'm not sure I would be trusting an installer that puts both "Solax" and "Solis" on the invoice.
3) I am concerned it is an MCB tripping (rather than an RCB or RCBO). An MCB will only trip on overload and has a very well defined time/current pattern that will cause a trigger. It is extremely unlikely that both MCB's were faulty, so we have to assume there is a short circuit on the line from the inverter to the CU. Could be cable damage / water ingress / foreign body ingress. A sparky would be needed to perform an IR test to investigate further.
4) A 16A MCB is sufficient for a 3kW inverter (my 3.6kW Solis ran fine for 18 months on a 20A MCB). A B-curve 16A MCB will not instantly trigger unless there is draw of 45A+ and will take up to 5 minutes before triggering at a very small overload situation. If the circuit powered by the inverter has many inductive loads on it, it may be worth trying a C-curve MCB, but it should not be necessary to increase the current rating above 20A IMHO.
5) Regarding current rating, the MCB is there to protect the wiring. What size wire do you have between the MCB and CU? In any case, make sure that the cable is rated at least 25% greater capacity than the MCB.
6) Lastly, is your Solis showing any alarm messages in the log? An ILEAK type error could be the trigger for an RCD / RCBO trip, though I still don't see why an MCB would trip unless there is a L-N fault or an overload situation.
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