Panel grounding question

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  #1  
Old 03-12-06, 08:28 AM
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Panel grounding question

Hi:

Recently had my deep well pump replaced...ran new 10/2 w/ ground submersible pump wire from the pressure switch (in the basement) to the new pump. Old pump was not grounded directly...existing wire was 12/2 w/out ground. Ground (technically "grounding conductor," I think) from panel was attached to one ground screw on the pressure switch, with a bare copper wire that runs to and is attached to the well casing connected to the other pressure switch ground screw.

My breaker panel is grounded with one copper conductor to a ground rod that is driven through the basement slab...actually, slab was poured around it. There is only one ground rod.

Question...would there be any benefit and/or does the code allow me to connect the well casing ground to the ground rod as a sort of (very deep) second ground rod? It would be easy enough to do.

Good idea or bad?

 
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Old 03-12-06, 01:42 PM
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Tom,

The NEC states that in the case of a Well Pump Casing as stated you should actually Bond the casing to the pump circuit equipment ground. It sounds like this is now present since you ran new wire with an actual ground within it.

The intent of the NEC 250.112(M) is to prevent a shock hazzard that could exist due to a potential difference between the pump, which is grounded to the system ground, and the metal casing.

As for it being an Grounding Electrode....It has been debated since Art 250.52(A)(7) proclaims "Other Local Metal Underground Systems or Structures "...but as for the pump itself 250.112(M) is clear on how to do this.

How far away is this Metal Casing Well Pump......? It may help to answer your question because I know the 2005 NEC is expanding on this.
 
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Old 03-12-06, 05:16 PM
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If you wish to run a GEC from the casing to the other electrode or to the panel, go right ahead.
There is no problem with doing this. You can only improve the situation.

It think it is a good idea.
 
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Old 03-13-06, 04:27 AM
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ElectricalMan:

The well casing is about 35 feet from the house.
 
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Old 03-13-06, 05:09 AM
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Tom,

The NEC will allow you to connect to this and it be considered a grounding electrode if you read the NEC article 250.52(A)(7) but the debate will go on in regards to if this is considered a piping system......but certainly will not hurt to have it connected to your GEC as part of the system.

However, due to the distance I would rather see you bond the supply circuit EGC to the case and be done with it....and at the panel drive an additional ground rod.....that what i would personally suggest.....the debate rides on in ragards to the Well Casing...
 
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