It is quite easy to trip the switches if you are using anything that consumes more than 1000W electricity like the iron/heater/clothesdryer/kettle/microwave at the same time. You might have a 10A switch which will only allow a max of 2400W through it before tripping it.
As for whether this is behind the broken appliances, I'm not sure. We are fortunate to have alot of cheap equipment from China in the last few years, but the componentry certainly isn't built to last like the 'old days'
I should also mention that NSW electricity supply is alot better than in some other parts of the country. My parents in Brisbane always suffer from brownouts caused by a shortage of power supply.