installed a Multiplus 2 5000 , one heavy loads board ( non back up ) ans a critical loads ( back up) ,the latter via the Multiplus . Typical draw on back up board is around 1kw when the customer turns kettle on and washing machine the inverter shuts down. Any sugggestions how to stop it overloading . i thought the inverter had a 50amp pass through current and was capable of handling these type of loads when grid connected ?