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Wednesday, December 21, 2022
Question:
Hello Code Question of the Day. Great job, please keep up the good work. I have a question regarding the water pipe and supplemental ground (ground rod) connection points to the service. The installation is a single-family home with a single meter socket, an exterior emergency service disconnect, and a main breaker panel.
From the meter to the disconnect there are 3 wires (2 hots, 1 neutral). The neutral and ground are bonded together in the service disconnect. From the service disconnect to the loadcenter there are 4 wires (2 hots, 1 neutral, 1 ground). In the loadcenter, all neutrals go to the (grounded conductor) neutral bar and all the equipment grounding conductors go to the equipment ground bar connected to the frame of the loadcenter. The neutral bar and equipment grounding bar in the loadcenter are not bonded together.
The question that has yielded several different opinions is as follows:
Where is it permissible for the water pipe electrode conductor, and supplemental grounding electrode (ground rod) conductor, to attach to the service?
Can either grounding electrode conductor be connected to the ground bar in the load center, or do both of them have to be attached in the emergency disconnect? Thanks, Rich Cressotti
A
Answer:
Richard, thank you for the kind words, glad to hear to hear you are enjoying the CQD content. There is a couple of layers to your questions, so we will unpack and address them each.
Section 250.24(A)(1) requires the Grounding Electrode Conductor (GEC) to be connected the Grounded Conductor, at any accessible point from the load end of the overhead service conductors, service drop, or service lateral (the utility conductors), to (and including) the Grounded Conductor (Neutral) bus or lug in the service disconnect.
If the Emergency Disconnect required by Section 230.85 is also serving as required Service Disconnect, then the GEC connection must be done there in the Service Disconnect/Emergency Disconnect and would not be permitted further downstream in the loadcenter as described in the first part of your question.
If the Emergency Disconnect were solely installed as the Emergency Disconnect using one of the methods listed in Section 230.85(2) & (3), the GEC connection would be permitted according to Section 250.24(A)(1). However, this would also be heavily dependent on the Listing, design, and enclosure size of the Emergency Disconnect.
One last piece to this puzzle, is the Metal Underground Water Pipe GEC connection vs the Supplement Rod, Pipe or Plate GEC connection. When installing a Rod, Pipe, or Plate electrode, as a supplemental electrode to the Metal Underground Water Pipe electrode, the GEC for the supplemental electrode can be connected to any of the following in accordance with Section 250.53(D)(2):
(1) Grounding Electrode Conductor
(2) Grounded Service Entrance Conductor
(3) Nonflexible Grounded Service Raceway
(4) Any Grounded Service Enclosure
(5) As provided by 250.32(B)