Q: When the washing machine is switched on, the fuse trips out. Changed the plug on the machine but still trips. Plugged a radio in the socket and it works. Does all this mean I need to change the fuse?

If it's the main circuit breaker going every time you turn the washing machine on, there are several possibilities. The first is that you have recently added something to that circuit that has taken the entire circuit over it's allowed amperage, causing the breaker to trip every time it tries drawing power. Secondly it could be that your washing machine has developed an electrical fault and is short circuiting the entire system whenever it switches on. Finally it could be a physical fault with either the circuit breaker or the wiring elsewhere.

To figure out if it's the washing machine itself (and I feel this is the most likely if nothing else has changed in your household recently), try plugging it into a separate mains power circuit. Most medium sized households will have at least 2 30amp circuits, just use an extension cable to plug it into the other circuit (you can figure out what is what by manually triggering the circuit breakers). If it trips this other circuit, the chances are that you need to get your washing machine looked at or replaced.

As with all electrics, if you are at all unsure, or cannot locate the problem by fiddling with extension cables and fuses, then get a qualified electrician out to take a look.