If we interchange live and neutral wires in an electric circuit, will it work? If it works, then why is it not prescribed?
It will almost definitely work perfectly fine. In fact much of Europe use Shucko plugs and sockets that really don't care which way they're connected. The connector to most of your home gadgets is a 2 pin "8" shaped plug. Again this doesn't matter or care which way round it's connected. Most of your tech will be double insulated, meaning that it has no metal frame which could become live in a fault situation. Additionally it probably works on very low voltages and so steps the mains voltage down internally.The reason that you shouldn't switch live and neutral is in the home wiring. This is protected by fuses, circuit breakers and an earth leakage circuit breaker for part or all of your house. Some appliances such as cookers, heaters etc draw a lot of current and have bare metal parts. Unsurprisingly any plugin device will have a fuse built into the plug. This fuse is only on the live wire and so a crossed over live and neutral would mean that instead of the live wire being protected it is the neutral. If a fault develops and the live touches a metal chassis there is no fuse to burn out. Neutral wires are not much different from earth voltage and so touching one isn't usually dangerous, hence they don't need to be fuse protected. Of course most homes will have earth leakage breakers fitted but a surprising amount still don't. So when wiring a plug ALWAYS make sure that you connect the red/brown write to the live (the one where the fuse is), the blue/black to the neutral (the one opposite the live and the green-yellow/green to the earth (the one at the top of the plug).
Why is earthing necessary in electrical systems?
To understand the “need” of earthing, we will try understanding what “earthing” or “grounding” mean and its benefits…Earthing or grounding simply means making an electrical connection to the ground (yes literally to the earth), but the way the connection is done has a process and a standard (more info on factors affecting earthing). Why do we do so? simple answer would be for “PROTECTION” of the human life or the electrical/electronic equipment…An earthing is a MUST for an equipment which has NO insulation and susceptible to a human contact - something like the water heaters, iron boxes etc…In case of an insulated equipment we still find the earthing to ensure safety for humans (Top priority) if the insulation fails… Coming to the second need, it is to protect the equipment itself- specially the electronic equipment - which are sensitive to external noise (Electromagnetic noises), static charges (Static electricity is a beautiful concept - refer to this link to understand the main cause behind a petrol bunk explosion)…By earthing an equipment how are we avoiding the peril to human life or a malfunctioning of an equipment? reason is simple: Earth offers a ZERO RESISTANCE path for any leakage current or a noise current - hence any current that would be a risk to human life or to the functionality of the equipment will be bypassed to destination which offers a least resistance path…The essence of a FARADAY CAGE application (LINK1 LINK2)…Earth has an enormous capacity to take in the free electrons as well as it serves as a source - The Earth’s Surface Serves as a Giant Source of Antioxidants in the Form of Free Electrons | Wake Up World
Why is it dangerous to swap the live and neutral wires in an electrical appliance?
If it has a 2 wire plug, basically nothing happens. It’s not anymore dangerous than plugging it in properly. (This is for modern devices)If it’s a 3 wire plug, it will do one of two things:Trip the breaker immediately because it’s not a proper 3 wire device.Do the same thing as the 2 wire plug. Work the same as it does.There is a voltage difference between Neutral and Hot. Neutral and Ground should have minimal difference, but ground is only supposed to be used in equipment failure state. During normal operation, it won’t matter on most things.I rewired an old barn about 8 years ago, and they kept complaining that they had to hire another person to hold in the GFI switch. (It’s a wet service location, so it all had to be GFI except the 220 stuff which was “special”.)Turns out the capacitor in the drill press shorted out to the frame. Some employees complained of feeling a slight buzz while using it. Solution? Hire another person to hold in the GFI. I had to laugh. I went back over and fixed the drill press. It had a rectangular capacitor that was “fixed” and installed upside down with no insulation. All remedied now.Fast forward a few years… All the GFIs were removed by a so called “electrician” and replaced with normal outlets. Some tools give the employees a little buzz now, but that’s how the owner wants it.I guess paying $40USD to fix an ancient drill is more expensive than paying someone else even more to remove the safety equipment.Generally though, with those 2 wire plug stuff, it doesn’t matter. The old stuff use to have neutral bonded to the metal frame of the device, that was BAD. The goal is that in a fault, the electrons travel from ground to hot, and it trips the breaker. It works.
What happens when a neutral wire touches a earth wire?
Nothing should happen. But you should not connect these. They are connected at the breaker panel. The reason you should not connect these is that they serve two different purposes. The neutral wire caries current. It completes the circuit from the hot side. The ground (earth) wire is not meant to carry current. It is a safety circuit that is meant to ground the body of the electrical box and the device you have plugged in to it. It keeps the device at the voltage level of the ground so that you, and the device are at the same potential.If you have a ground fault circuit interrupter (GFCI), then connecting neutral and ground will fault the circuit. The GFCI compares the current in the hot wire, to the neutral wire. If there is any difference (like when some of the current flows through the ground wire) then it cuts the circuit.Keep in mind that AC electrical wiring should not be played with. If you wire something wrong, any consequence of that will be your fault. Insurance will not cover a fire caused by your mistake. Nothing will cover someone getting electrocuted. Please get some guidance from someone who is qualified.