Service Neutral Used as Ground

For the electrical gurus out there, sorry for all the questions.

  1. Can the service neutral be considered/used as the GEC in any situation? I had an electrician tell me that in our main county, the AHJ considered the service neutral the ground when the water line servicing the house is plastic.(assuming I didn’t butcher what he said).

  2. If this is the case or something similar is correct, how is this possible if the service neutral is carrying a load?

  3. I know they try to balance the panel, but how realistic is it to get both phases carrying a similar load so that the service neutral is at 0 potential?(again, assuming I didn’t just verbally butcher that as well)

  4. Is this a cop-out by the AHJ and should an inspector call out the lack of a GEC in a panel if this is the setup, assuming the panel isn’t connected thru metal conduit to a GEC at the meter?

Thanks for any clarity you can provide and I apologize if I have abused/misused any principles, theories or terminology in the writing of this post. I still haven’t decided if working on eletrical systems is more dangerous than asking questions about them on a forum. :smiley:

The neutral is bonded to the GEC in a service panel. This is done with a bond screw or strap. The neutral is not used as a GEC. The GEC commonly goes to rods, Ufers or other electrodes. If a metallic water line in direct earth contact for 10 foot or more it too would be an electrode.

Balancing a single phase residential panel is useless. The loads shift in the panel as life moves from the kitchen to the living room to the bedrooms. The 240 volt loads are already balanced between the two hots. The neutral is calculated to carry the unbalanced current and is full sized in some services. A reduction is allowed if the calulations show it can be smaller.

All grounding of metallic electrical parts on the line side of the service disconnect is accomplished by bonding the metal parts to the neutral conductor. There is no EGC on the line side.

As far as there being no water pipe electrode the NEC requires a GES or grounding electrode system to be present at the structure for connection to the service. Article 250 has a list of electrodes that can be used when a metallic water pipe is not present to form a GES.

So basically, if I come upon a panel with no GEC running to a water pipe, ufer or rod driven outside(or other acceptable electrode), the neutral in this situation is not considered a substitute according to the NEC? I read a good portion of NEC article 250 and I didn’t see any exception like the one that electrician described.

Yes, a grounding electrode system (GES) is designed to do what is outlined in 250.4(A) and some form of a GES is required. If no electrodes are present than the typical minimum for a GES would be two ground rods.

Even without a GES or a GEC the system will still provide protection because the metallic parts of a properly installed systemwould still be connected to the neutral at the service through the system bonding jumper, typically a green screw in the neutral bus.