Why didn't the fuse blow?

[Garry]

I noticed that my keggle stopped heating today. I took the plug apart and the live wire was scorched to $hit. But when I check the fuse in the plug, it still has continuity. Why didn't it blow?

[Shane Phelan]

This has happened to either a poor connection with the live section of the plug or some of the copper getting stripped off during wiring. If the quality of the neutral wiring is anything to go by, not all the copper strands were making contact with the plug which then overloaded the ones that were connected creating heat. You wouldn't need 13A to create that heat.

[Garry]

My own fault so  : I better double check the other plugs. I was thinking of changing all the cables to solid wire instead of stranded.

[mcgrath]

Happened to me with an extention lead for washing machine and drier. Just melted and stoped working. Remember thinking the same thing..

[LordEoin]

When you're wiring the next plug, strip twice the length you need.
Then double it back on itself, and twist it up tight.
You'll get a much better connection and the titghening screws won't strip off stray bits of wire.

paint to the rescue:

[Garry]

That's what I normally do too but this is 2.5mm2 wire. When I double it up it won't fit in the hole 

[Will_D]

So if you are using 2.5 mm2 cable how many kilowatts are you pulling?

Remeber that 13 amp fuses do not blow at 13.1 Amps!

They usually blow at 26 Amps!

If you are over running them the fuse will get hot and will "age" prematurley and then eventually blow at less than 100% overload.

However it does just look like a loose connection.

Other thing to remember is that a properly wired plug can still get hot if the socket is not making a good connection.

If you are running plugs at full 13A wack then after about 1/2 hour wip the plug out and carefully see if the pins are getting hot. If they are and the plug is not the suspect try another socket!

[Damien M]

The V=IR of what happened is .... 

As the cable termination started to burn/oxidise the Resistance there started to increase thus decreasing the I(current) through the Fuse and as the the resistance at that point increased its a vicious  circle, resistance heat making the problem worse until 1 of 2 things happen. The burning of the cable breaks down until it cannot carry current any more and stops, or heats up to the combustion temperature of the plug components and Kablamo!

All Bad! Key point being don't scrimp on the safety stuff! No Pound shop Plugs!!!  :