A toaster cable with conductors coloured red, black and green is to be joined to another cable with brown, blue and green/yellow conductors. Peter has joined the red and blue, black and brown, and green and green/yello. Will the toaster work normally when it is plugged in and turned on? Why is the way he has connected the cables dangerous?
The answers say: "Yes it will work, but it will remain live when off."
Could I get a clear explanation for why that is?
The answers say: "Yes it will work, but it will remain live when off."
Could I get a clear explanation for why that is?
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The live wire is at a high voltage. (In fact the voltage varies rapidly, as we are dealing with AC - but for the sake of a simple explanation, treat the live wire as being a high voltage)
The neutral wire is at zero volts. (Again, this is a bit of a simplification. It should be at zero volts but can sometimes have a small voltage.)
The earth wire is at zero volts because it is connected to the ground (which is defined to be at zero volts.) Normally it carries no current and is there for safety in conjunction with the fuse - but I won't go into that here.
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You get a current if there is a voltage difference (e.g. between live and neutral or live and earth (which shouldn't happen)) across a conductor.
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IMPORTANT BIT
The switch in the toaster is connected to the live wire. When the switch is open (off), all the components inside are isolated from live, but are still connected to neutral. That's a key point.
If the live and neutral wires are the wrong way round, even when the switch is off, all the components inside are now directly connected to live, so you could get a shock even though the switch is off.
(Also, for information, the earth/fuse system won;t work properly, since the fuse is connected, before the switch on the live side.)
Hope that make sense. It's difficult without diagrams.
The neutral wire is at zero volts. (Again, this is a bit of a simplification. It should be at zero volts but can sometimes have a small voltage.)
The earth wire is at zero volts because it is connected to the ground (which is defined to be at zero volts.) Normally it carries no current and is there for safety in conjunction with the fuse - but I won't go into that here.
______________________________________…
You get a current if there is a voltage difference (e.g. between live and neutral or live and earth (which shouldn't happen)) across a conductor.
______________________________________…
IMPORTANT BIT
The switch in the toaster is connected to the live wire. When the switch is open (off), all the components inside are isolated from live, but are still connected to neutral. That's a key point.
If the live and neutral wires are the wrong way round, even when the switch is off, all the components inside are now directly connected to live, so you could get a shock even though the switch is off.
(Also, for information, the earth/fuse system won;t work properly, since the fuse is connected, before the switch on the live side.)
Hope that make sense. It's difficult without diagrams.