flow of electricity from pole to panel

[Dg01501]

to keep it simple we will just say this is a dwelling. my question is directed towards the flow of electricity from the pole to a point of utilization in the home. lets say you connected a light to a circuit, the electricity leaves on the hot wire, hits the light and returns on the neutral/ground bar at the panel. from there where does the electrical energy go? back to the pole to a transformer...or does it go through the ground rod to the earth? people have told me that it goes back to the transformer and others back to earth through the grounding electrode. could anyone clear this up for me?

 

[George Stolz]

To the transformer, mostly through the neutral, a little bitty bit through the earth to the transformer. Electricity seeks all paths back to it's source, according to their resistances. See the grounding and bonding forum sticky thread, "The Big Picture."

Welcome to the forum.

 

[kwired]

Now lets complicate it some more. Put another light the same size on the other hot conductor. Now current flows through the first light back to the neutral bus then down the neutral conductor of the second light and back on the second hot conductor. There may be current traveling back to transformer over grounded conductor and other mentioned paths but is nearly unmeasurable if both lamps are identical and conditions of the circuits are identical.

 

[George Stolz]

Let's complicate it for him. :slaphead:

 

[kwired]

Let's complicate it for him. :slaphead:

Want me to explain the same thing but with a 3 phase MWBC?

 

[Dg01501]

lol...yea im confused now, i do get the idea but not the whole picture. i need to brush up on my theory

 

[kwired]

Since the POCO transformer has the neutral 'earthed' and the service in the building where your light is also has the neutral conductor 'earthed' via the grounding electrode system, the earth although not a very good conductor is in parallel with the neutral conductor.

Your neutral conductor and earth are parallel conductors of differing resistance.
Because the earth has a high resistance in comparison to the neutral conductor almost all of the current flows in the conductor but there is some going to flow through earth.


Does that simplify it enough?

 

[broadgage]

Under normal conditions very little of the load current will flow through the ground rod and the general mass of earth, a little will but not much.
There are two paths from the neutral/ground bar at the service back to the transformer.
The lower resistance path is the neutral wire, and the great majority of the current takes this route.
The higher resistance path is via the ground rod, and only a very small part of the current will take this path.

If the ground rod was missing the installation would still work.
It would be less safe, and a code violation, but it would work without the ground rod.

 

[Dg01501]

thanks, that did simplify it for me...sorry if this is a noob question but at the transformer does the current returning on the neutral get reused and sent back to the panel on a phase conductor or does it simple dead end?

 

[roger]

Click here for a good explanation of electricity flow.


With a little humor.

Roger

 

[kwired]

thanks, that did simplify it for me...sorry if this is a noob question but at the transformer does the current returning on the neutral get reused and sent back to the panel on a phase conductor or does it simple dead end?

It can't dead end otherwise you have an open circuit. To keep it simple lets just talk about a 120 volt load and current path from a 120/240 transformer. The current will flow from an ungrounded terminal lets call it L1, through the service drop or lateral through the overcurrent devices, branch circuit, control devices and eventually the load. Returning from the load through a different conductor but otherwise all previously mentioned items except for overcurrent devices and back to neutral terminal on transformer. Within transformer the current will flow through winding back to L1 to complete the circuit. The portion of the transformer between neutral and L2 is not used at all for this circuit.

Now start adding load to L2 and current from L1 comes back to neutral bar and goes out a neutral connected to a L2 load through the L2 load eventually back to L2 on transformer and through transformer windings eventually to L1. That is if perfectly balanced L1 and L2 loads. If unbalanced loads the unbalanced portion of the neutral current flows back to transformer terminal and toward which ever leg has the higher load on it.

Hope this was simple enough to grasp also. Pictures would simplify it more which I may be able to do if you want.

 

[Little Bill]

Click here for a good explanation of electricity flow.


With a little humor.

Roger

Wasn't expecting that, I liked the part about the frog. This was the funniest thing I've seen in a while, and the funniest ever about electricity!:lol: