I have a question about electrical grounding. As I understand it, every electrical item found in the home with a metal casing, or copper plumbing, is earthed and is connected together to a rod in the ground. However, what I do not understand is this: this configuration also means that all metal appliances, plumbing, etc, are all linked together, and therefore, if one electrical appliance developed a fault which lead to its metal casing to become live, then surely every other item in the house with a metal casing, plumbing, etc, would also become live? of course, at this point the fuse would blow, or the RCD would kick in. But it would still mean, for a split second, that anything metal is dangerously live in the house, not good if your in a metal bath, or washing dishes in a metal sink? why is this not a problem? or is my understanding wrong?
2007-09-24 09:40:47 · 6 answers · asked by boyinlove2k 2 in Science & Mathematics ➔ Engineering
The electricicty will always take the path of least resistance in this case to the ground, so even you were to touch the casing or enclosure of any of those items for that split second, electricity wouln't flow through you... instead it would flow to the earth throught the ground system.
2007-09-24 09:56:17 · answer #1 · answered by Chuck 2 · 4⤊ 0⤋
you are right to assume that all metal casings appliances and plumbing would become live for a very short period due to being electrically(bonded)together..this is what makes them safe as electrical current always takes the path of least resistance and that would mean by ways of all metallic wiring and pipework that are inter connected and lead to earth..this means any fault current goes straight to earth and even though someone might be in direct contact current would not circulate through them as their body resistance would be of a considerably greater value than the fault circuit(earthing circuit)this is why an inadequately bonded sink can give off shocks and have been known on occasion to be fatal
2007-09-24 10:10:56 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The object of the exercise is that if a components' outer casing(the bit you might touch) becomes connected to the live wire the current in the circuit will rise very rapidly and blow the fuse in the live line.This means that only the live wire accidentaly connected connected to earth is switched off by the fuse 'blowing'.It's the reason you should be careful to check for a reason for the blowout before replacing the fuse in the 3-pin plug.
2007-09-26 10:29:54 · answer #3 · answered by L D 6 · 0⤊ 0⤋
You'd be right if the metal in question wasn't earthed along with everything else. It's only when the ground connection at the power entry fails to make contact that a dangerous condition might develop.
Doug
2007-09-24 10:23:46 · answer #4 · answered by doug_donaghue 7 · 0⤊ 0⤋
The only time you'd get a shock under fault conditions is if the appliance WASN'T earthed, then you would be the path of least resistance
2007-09-24 11:35:21 · answer #5 · answered by Anonymous · 1⤊ 0⤋
Chuck is correct
2007-09-24 11:59:11 · answer #6 · answered by Radiator 4 · 0⤊ 0⤋