84
votes
Accepted
Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?
simulate this circuit – Schematic created using CircuitLab
Figure 1 and 2. showing the danger of earthing through neutral.
In the first example the Lunatic 'Lectrician has 'grounded' the lamp ...
- 171k
59
votes
Accepted
What is the right way to float a home lab?
You can't float everything without an isolation transformer - the neutral will be connected to ground at the entry into the building. For safety any class I equipment does need to remain grounded, in ...
- 5,609
57
votes
Accepted
Why is main's neutral tied to earth?
There are four reasons for grounding the neutral.
1. Grounding neutral provides a common reference for all things plugged into the power system. That makes connections between devices safe(r).
2. ...
- 46.5k
55
votes
Accepted
Is ground connection in home electrical system really necessary?
What you are not considering is that an earthed chassis or metal box containing a "rogue" live connection will be self-revealing should a fault occur that causes live to touch the earthed ...
- 444k
42
votes
"Ground" vs. "Earth" vs. common vs. negative terminal
Problems:
First, currents don't "come from" the positive terminal. That's a very common misconception, an error called the "sequential fallacy" appearing widely in grade-school ...
- 10.8k
23
votes
Ground Symbol, which one I should use?
Whether to follow the IEC spec or some other convention is up to each company individually. If your boss says to use the IEC one, use the IEC one.
- 128k
22
votes
How to stop plastic granules sticking to the iron wall of their silo?
If your plastic pellets are getting charged, you can flood the inside of the silo with ionized air using a commercial generator. These are not uncommon in the plastics industry.
- 385k
21
votes
Accepted
Is the link between the earth/chasis terminal and the utility transformer established through a dedicated wire or the soil?
There's more than one way to skin this cat, even to this very day
While there is a global standard for mains earthing systems, IEC 60364 to be precise, it does not set out a single means of mains ...
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20
votes
Accepted
Safest way to ground a metal enclosure
Option 4: bond the enclosure to earth, and connect it to the clock ground with a high impedance, maybe 1 megohm.
This prevents large voltages building up between the internal circuit and the enclosure,...
- 128k
18
votes
Why is main's neutral tied to earth?
What you're talking about is an isolated system. I have an extended treatise on it here. In an isolated system, "the first ground fault is free" (and becomes the neutral-ground bond). This is the ...
18
votes
Ground Symbol, which one I should use?
Ground Symbol, which one I should use?
The following would be of help to decide which symbol would be appropriate.
1. Earth ground
This is related to protective earthing of mains operated electrical ...
- 17.5k
15
votes
USB peripheral: connecting USB shield to GND?
I don't think there's a lot of conflicting information, but rather a lot of information that depends on context or EMC notions.
To understand, it's important not to confuse these symbols. Zero volt (...
- 813
14
votes
Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?
While usually neutral wire and earth wire are at the same potential, and can therefore be effectively swapped from a purely electrical point of view, the way they are connected makes them very, very ...
- 16.1k
14
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Why is main's neutral tied to earth?
On an IT-network, where both lines on the socket are live, the GFCI wouldn't work on a single fault.
Which has benefits in in some high continuity systems (eg: operation rooms), a single fault doesn't ...
- 22.3k
13
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How many "grounds" are there and what is the difference?
There are infinitely many ground symbols, as you can call anything ground. On some projects I have seen GNDA GNDB GNDC... etc.
A ground is a common reference voltage. No ground is truly 0 volts, but ...
- 78.1k
11
votes
Amplifier does not sound right when balance is centered
Reverse the polarity of one of the speakers. It sounds as though you have one of them reversed and so they are out of phase. Vocals and bass are usually centered in the stereo panorama and when they ...
- 171k
11
votes
What is the right way to float a home lab?
What is the right way to float my home lab?
If you want to make measurements that are isolated from ground, the only way to do this is with an isolation transformer if your scope is not isolated. ...
- 78.1k
11
votes
Accepted
Dangers of floating oscilloscope
I believe the situation in the video is such that a scope is used for debugging the unisolated mains side of a fly-back type switch mode power supply.
As no point in the unisolated side is at ground ...
- 138k
10
votes
Accepted
In any electrical equipment having single ph 230 v ac supply ,if neutral and earth wire exchanged then what will be the consequence
There is a problem.
Generally the neutral and earth are connected at source. On fixed installations (e.g., your house) this may be the local transformer or at your meter-box, depending on local ...
- 171k
10
votes
Is ground connection in home electrical system really necessary?
In addition to Andy's answer, a floating supply may require dual circuit-breakers on each circuit to trip both lines as you can't predict which phase will be "neutralized" by the first fault....
- 171k
10
votes
Should RVs electrical system be grounded to chassis?
Grounding of RVs is a complex question, and the correct approach is dependent on the details of the supply earthing system.
Based on the reference to 230V I'm going to assume you're in the UK, in ...
- 6,311
9
votes
Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?
Vladamir has the important answer: we treat the two conductors differently, even though they are nominally at the same voltage. He gives the example of a RCD, and the GFCIs you see in modern US ...
- 2,906
9
votes
Accepted
Are countries that use 2-pin plugs less safe than countries that use 3-pin plugs given that the earth is missing?
That is actually an interesting question.
The truth is... it is complicated.
Consider the following three connection systems.
simulate this circuit – Schematic created using CircuitLab
The ...
- 46.5k
8
votes
Why is main's neutral tied to earth?
As Neil has pointed out, the big picture is that you are part of a big electricity network, and if it wasn't grounded somewhere, the whole damn thing would float high - perhaps to $lightning volts.
...
- 5,343
8
votes
The chance of a lightning strike - reduced or increased?
It would increase the likelihood of the receiver getting struck, but the chance of getting hit would still be small. To understand this, we need to start with a description of how a lightning rod ...
- 2,632
8
votes
Safest way to ground a metal enclosure
From a safety standpoint the enclosure should be connected to earth, not to the neutral leg of the power supply. You should have a three prong plug with the enclosure connected to the ground pin. ...
- 260
8
votes
Accepted
When do I need a protective earth?
There's a lot of misconception around CE marking and other regulatory issues.
Of course, electrical safety is mandatory. All devices sold must be safe, i.e. state of the art. Luckily you don't have to ...
- 3,876
7
votes
Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?
Answering the question in the edit:
If the bulb is connected this way:
If the customer touches the lamp when it is switched on, I do not thing she >will notice a slight ...
- 21.7k
7
votes
Resistor or low impedance path between common ground point and mains earth?
If by plan B you mean to add a resistor to the mains ground, then no plan B is not an option. If you add a resistor in series you will have two problems:
1) It affects the saftey of the earth mains,...
- 78.1k
7
votes
What is the right way to float a home lab?
There is no right way to float your home lab.
1) No. Right way is not to float equipment that must be grounded.
2) No. Don't float any of them. Equipment that have grounded plugs NEED to be grounded ...
- 138k
Only top scored, non community-wiki answers of a minimum length are eligible