I suspect that the new LED lighting has a high crest factor, where Crest factor is the peak amplitude of the waveform divided by the RMS value of the waveform. So when a number of new LED fittings are supplied by the original mcb the electromagnetic functionality of the mcb detects the high total peak current and trips the breaker. The rms value is low and therefore there is insufficient Ohmic heating to cause the thermal functionality of the mcb to operate.
This is why there is a limit on the number of LED fittings per mcb size - you mentioned 5. I suggest you modify the wiring to power the lighting from 2mcbs, 5 LED strips on each. Or a higher current mcb if the wiring allows to power all 10 but this is not to be preferred.
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