Grounding Question

[mdjakhi]

Hi guys,
I'm trying to better understand how grounding works. I got the basic idea of it, but still have a lot of questions about it. K, so from my understanding, if you touch the neutral bar on a service panel you will not get shocked (because it is grounded). But why do you get shocked if you touch the hot wire on a closed circuit? Isn't the circuit grounded? you're just touching it at a different place that's all...

 

[mdjakhi]

by the way im not going around touching wires lol, i'm just trying to understand how it works.

 

[Deleted member 26818]

The Neutral is a return path for the current.
The ground or Earth is just another return path.
If there is a high resistance on the Neutral and a lower resistance on the Earth, you will get a shock.

 

[SparkyChick]

You have Line (hot) -> Load -> Neutral.

When you close a breaker, you apply line voltage to the line (hot) feeding the load. Because the line has negligible resistance, the voltage drop is small, so it will effectively be at line voltage across it's entire length.

The most basic load is a resistor. Resistors turn power into heat. So, if you have a 230 ohm resistor connected across the mains, using Ohms law it will consume 1A (I = V/R) and dissipate 230w of power. So, the terminal connected to line will be at 230v with respect to earth and the terminal connected to neutral will be at 0v with respect to earth.

That's why you can touch the neutral and not the line (hot), although if there is a fault, it is possible the neutral will be at a potential above the safe touch voltage so I wouldn't recommend you make a habit of it.

 

[PEG]

Hi,the most important issue to consider,if one is keen to go round touching things,is potential.
This,in short,is the voltage between two points,in this case,you,and what you are prodding.

If you were stood,on a tea tray which was live,with no other part of your body in contact with anything,and you touched a live conductor,from the same supply,you would feel nothing.

Step off,that tray,and your risking dire consequences.

To understand potential,is the key to assess risks,and know how certain low-voltage systems,such as 110V,mitigate against the risks,electricity can pose.

It is the reason for neutral,which in theory,is linked to earth,is categorised as a "live" conductor.

Patting at sleeping dog,will not mean you won't get bitten