ItsElectricBoogieWoogie
Member
If you have voltage between Hot and ground Why when touching the ground do you not scence this votage? Why do you not get electricuted in the main pannel when touching the neutral and block?
Beginner question please help
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Hameedulla-Ekhlas
Senior Member
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- AFG
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- Massachusetts
Yes there will always be a bit of voltage drop on the grounded conductors causing a difference of potential between neutral and ground but in most cases it is not enough of a difference to overcome our skins resistance.
That does not just occur in just 3 phase installations. However, I do not think that was the question the OP asked.
LarryFine
Master Electrician Electric Contractor Richmond VA
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- Henrico County, VA
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- Electrical Contractor
Mr. Woogie, welcome to the forum! 
(Got a real name, or should we call you "Its"?)
If you touch one of the white wires while grounded, it wouldn't shock you. But, if you disconnected a white wire from the neutral bus, and any load on that circuit was on, the white wire would shock you.
(Got a real name, or should we call you "Its"?)Because there's (practically) no voltage difference between the neutral bus and anything else, except the hot wires. If you were "standing" on one of the hot wires, the neutral bus would shock you.
If you touch one of the white wires while grounded, it wouldn't shock you. But, if you disconnected a white wire from the neutral bus, and any load on that circuit was on, the white wire would shock you.
A shock (or the sensation thereof) is dependent on the voltage across two points of body contact (in the low voltage [LV] reqion of electrical power systems). Touching most any LV wire will not shock you unless your body is also touching something else of different voltage potential. For example, if your boots are great insulators, and while steading you touch an energized with 120V AC conductor and nothing else, you will likely not get shocked. NOTE: Do not attempt this as an actual experiment, even if you are a professional
A relatively safe experiment can be done using a charged 9 volt battery. Touch either terminal with your tongue and you will not be shocked... but touch both at the same time with your tongue....
A relatively safe experiment can be done using a charged 9 volt battery. Touch either terminal with your tongue and you will not be shocked... but touch both at the same time with your tongue....
kingpb
Senior Member
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- SE USA as far as you can go
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- Engineer, Registered
You can, it is why step and touch potentials are calculated, and ground grids are installed.
That being said, in theory, if you have a balanced system, and without a bunch of power switching devices, i.e. all resistive load, you would not feel a shock IF insulated between your feet and floor.
In reality, I would not recommend this, as it is impossible to completely balance a system, and there are many outside influences that can effect the outcome. Electricity is not something to fool with.
broadgage
Senior Member
- Location
- London, England
Yes, as others post, one must be in contact with ground and a dangerous voltage in order to get a shock.
It should IN THEORY be safe to touch an energised conductor if completly insulated from ground. DONT try it though since a mistake could kill you.
A good illustration of this is high voltage overhead lines. Every year people die from touching these whilst in contact with the ground, or grounded articles, yet birds perch upon these conductors without harm.
That is because current can pass through the person, from line to ground, and most likely kill them, the bird however is well away from ground and suffers no harm.
It should IN THEORY be safe to touch an energised conductor if completly insulated from ground. DONT try it though since a mistake could kill you.
A good illustration of this is high voltage overhead lines. Every year people die from touching these whilst in contact with the ground, or grounded articles, yet birds perch upon these conductors without harm.
That is because current can pass through the person, from line to ground, and most likely kill them, the bird however is well away from ground and suffers no harm.
ggunn
PE (Electrical), NABCEP certified
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- Austin, TX, USA
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- Consulting Electrical Engineer - Photovoltaic Systems
I saw a piece on the history channel about the guys who work on high tension lines from helicopters. The helicopter has to make electrical contact with the line first before the lineman can step over so that the charge differential doesn't fry him. The helicopter flies off and leaves him up there to do the work, but until it is grounded it retains a charge at whatever voltage the line was when it disconnected, so the pilot has to be sure the charge is dissipated before he can get out. When he goes back up to pick the lineman up, he has to connect to the line again before the guy can get back on board. All the time this is going on, the wind is trying to blow the helicopter out of position. Whatever those guys get paid, it's not enough.
Another way to visualize this would be a flash light lamp and a battery, the filament in the lamp does not have any current flowing through it in order to drop voltage until it comes in contact with both ends of the battery, so touching the lamp to one end of the battery does nothing since this is an open circuit
This is basically the same thing as being explained by the others.
When you only touch one part of a circuit there can be no voltage drop across your body, but let me reiterate that it isn't a good idea to be testing this.
Roger
This is basically the same thing as being explained by the others.
When you only touch one part of a circuit there can be no voltage drop across your body, but let me reiterate that it isn't a good idea to be testing this.
Roger
ItsElectricBoogieWoogie
Member
Hi guys, Thank you very much for answering. This website is great I can't wait to use it more. Im still not to clear on the question does any one know of any basic theory books or even better online videos? To see how the voltage travels from The pannel and then to the device and how its split up into circuits?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
For many concepts in electricity the analogy of water in pipes helps to visualize things. For example, in the case of a distribution panel, it is similar to water coming into a manifold; there is a big pipe feeding in and a bunch of valves (breakers) feeding smaller pipes going out.
mivey
Senior Member
Gene Simmons can do that with a series of 1.5 volt batteries. :grin:A relatively safe experiment can be done using a charged 9 volt battery. Touch either terminal with your tongue and you will not be shocked... but touch both at the same time with your tongue....
mivey
Senior Member
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