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In trying to understand the science of grounding, am I correct in saying that the main reason for the GEC is to enhance the grounded conductors reference to earth?
A grounding electrode can not make a neutral the same potential as the earth if there is a real electrical connection forcing the neutral to be of higher potential than the earth.Originally posted by pierre:
"That statement means nothing."
I agree it may not be the most important part, but... means nothing?
You don't even need an open neutral to have voltage and current on the grounding system. nall utility systems where the primary distribution is a grounded system, there will be a voltage equal to the voltage drop on the primary neutral at the grounding electrode system. There is nothing that you can do to eliminate this voltage. In fact the NEC even requires that we energize our pools with this voltage.A grounding electrode can not make a neutral the same potential as the earth if there is a real electrical connection forcing the neutral to be of higher potential than the earth.
Imagine a service that the utility neutral has opened.
Don I agree, I was just trying to provide a clear example.Originally posted by don_resqcapt19:
You don't even need an open neutral to have voltage and current on the grounding system.
Can you elaborate? I don't understand.Originally posted by don_resqcapt19:
In fact the NEC even requires that we energize our pools with this voltage.
I am confused. Can you explain the FPN of 680.26(A)?Originally posted by iwire:
The required equipotential grid is tied directly to the utility's neutral.
Cool analogy.Originally posted by iwire:
Thinking a grounding electrode will electrically connect an electrical system to earth is akin to thinking a sail is mechanically connected to the wind blowing on it.
I can give it a shot.Originally posted by georgestolz:
I am confused. Can you explain the FPN of 680.26(A)?Originally posted by iwire:
The required equipotential grid is tied directly to the utility's neutral.
Habit?Originally posted by m73214:
OK....So why do we run a GEC, be it a connection to a water pipe, concrete encased electrode, groung ring, ground rod or building steel or all of the above to the grounded conductor to a service? Is it simply for lightning protection?
In view of the wording in 680.26(B)(4) I cannot.I am confused. Can you explain the FPN of 680.26(A)?
Don(4) Electrical Equipment ... Where a double-insulated water-pump motor is installed under the provisions of this rule, a solid 8 AWG copper conductor that is of sufficient length to make a bonding connection to a replacement motor shall be extended from the bonding grid to an accessible point in the motor vicinity. Where there is no connection between the swimming pool bonding grid and the equipment grounding system for the premises, this bonding conductor shall be connected to the equipment grounding conductor of the motor circuit
For the most part that is the reason.OK....So why do we run a GEC, be it a connection to a water pipe, concrete encased electrode, groung ring, ground rod or building steel or all of the above to the grounded conductor to a service? Is it simply for lightning protection?
See, Edison knew that in the lab, conditions could be controlled, however wiring in the field would not and could not be.It is the general opinion of the Edison interest that, while absolute insulation, if it can be had and where it can be had, is preferable, the advantages of grounding the neutral under certain conditions and particularly on large systems, are such as to make that practice in those cases the best working method particularly as a precaution against fire risk.