The live and neutral wires of a 220 V supply touch where the insulation is worn.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The live and neutral wires of a supply touch where the insulation is worn. The path has a resistance of only . Find the current, the heat made each second in the path, and how many times a normal this current is.
Need a reminder? The key ideaShow
House circuits are in parallel at , with a live, a neutral and an earth wire. The current of an appliance is , and the currents add up. A fuse in the live wire melts when the current is too large (a short circuit or overloading). The earth wire joins a metal body to the ground.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The current. .
Step 2. The heat. , so each second.
Step 3. Compared. times.
Answer: , each second, times a normal current.
Check. No house wire can carry this: the fuse must melt at once.
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