January 30Jan 30 I have a 8kw Sunsynk, with 18 550watt panels and 3 x Bsl batt Powerline 5 batteries. I have noticed every now and then, when Eskom has a failure, my inverter trips in the inverter DB boxWhy would that be
January 30Jan 30 1 hour ago, FransSmith said:I have a 8kw Sunsynk, with 18 550watt panels and 3 x Bsl batt Powerline 5 batteries.I have noticed every now and then, when Eskom has a failure, my inverter trips in the inverter DB boxWhy would that beWhat size MCB feeds the inverter in your DB?
January 30Jan 30 1 hour ago, FransSmith said:I have a 8kw Sunsynk, with 18 550watt panels and 3 x Bsl batt Powerline 5 batteries.I have noticed every now and then, when Eskom has a failure, my inverter trips in the inverter DB boxWhy would that beWhat type of breaker trips EL? or can you post a pictures of the DB and the breaker that trips?
January 30Jan 30 Author 3 hours ago, Stefan Cornelissen said:What type of breaker trips EL? or can you post a pictures of the DB and the breaker that trips?
January 31Jan 31 Author 20 hours ago, Stefan Cornelissen said:is it this one tripping?Yes, that is the one tripping
February 1Feb 1 On 2026/01/30 at 1:36 PM, FransSmith said:I have noticed every now and then, when Eskom has a failure, my inverter trips in the inverter DB boxWhy would that beIn this case only the inverter output MCB trips, and only intermittently when Eskom drops. That points to load-dependent inrush during islanding, not a neutral fault. At switchover the Sunsynk takes full load instantly, and depending on what’s running, the transient can exceed a 63 A Curve C magnetic trip. Replacing the output breaker with a 63 A Curve D gives higher inrush tolerance while remaining within cable limits. Edited February 1Feb 1 by TaliaB
February 8Feb 8 I suspect that some of your breakers in the DB box were prepopulated with 63A 3Ka breakers?TaliaB has the solution.I only learnt the difference a few months ago when my Inverter Load Breaker had failed for the second time and an electrician friend told me to buy at least a 6Ka breaker for my setup which is feeding a 11KW Axpert inverter. Now, whenever I need to replace a breaker at work or the holiday home I do so with at least a 4.5Ka or preferably 6Ka breakers. Your average sparky when asked to replace a failed breaker will buy the cheapest 63A 3Ka breaker, only to fail again later when as TaliaB mentions you need higher inrush tolerance for the inverter.Obviously 6Ka or as TaliaB has suggested a 10Ka breaker, will cost more than the usual 3Ka variety.
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