ddivito
(Dennis DiVito, VA License # 3380 000170 NRS)
1
I saw an exterior panel next to the meter wired and bonded correctly. No grounding wire (from earth) to be seen in the panel, however, the grounding wire entered the building below an LB connector and was connected to the neutral/grounding bus bars in the interior distribution panel. The neutral and grounding wires were not on separate bus bars, they were connected. When the interior sub-panel is corrected, the grounding to earth path will be broken(?)
I will recommend having a licensed electrician connect the exterior grounding wire in the exterior main panel and correct the interior sub panel.
You’re saying that the service disconnect is adjacent to the meter but the “ground wire” goes into the sub-panel?
Something to make this easier, the “grounding wire” is the grounding electrode conductor (GEC). The GEC can terminate anywhere between the service disconnect enclosure and all the way back to the service point where the utility and premise wiring meets.
You are correct, since the interior panel is setup as a sub-panel the neutral and EGC’s must be separate. There needs to be an EGC run with the feeder to the sub-panel meaning that it needs a 4-wire feeder, or 3 physical conductors and an approved metal raceway that can serve as the 4th conductor, the EGC.
The defect is that the Grounding Electrode Conductor is connected on the load side of the Service Equipment inside the cabinet of a feeder supplied panel. The US National Electric Code requires that the Grounding Electrode Conductor be connected on the supply side of the Service Equipment between the Point of Connection of the Service Conductors to the Service Drop or Service Lateral and the Grounded conductor in each service equipment disconnecting means enclosure.
Individual Grounding Electrode Conductors. A grounding electrode conductor shall be connected between the grounding electrode system and one or more of the following, as applicable:
(1) Grounded conductor in each service equipment disconnecting means enclosure
(2) Equipment grounding conductor installed with the feeder
(3) Supply-side bonding jumper
Service Equipment. The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s) and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the supply.
Grounding Electrode Conductor. A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.
Service Drop. The overhead conductors between the utility electric supply system and the service point.
Service Lateral. The underground conductors between the utility electric supply system and the service point.
Service Point. The point of connection between the facilities of the serving utility and the premises wiring.
Informational Note: The service point can be described as the point of demarcation between where the serving utility ends and the premises wiring begins. The serving utility generally specifies the location of the service point based on the conditions of service.
The initial recommendation was correct by having the electrician move the GEC from the sub-panel to service disconnecting means and separating the EGC’s and neutrals in the sub-panel. Since there is already an EGC in the feeder that should be a simple task.
“When the interior sub-panel is corrected, the grounding to earth path will be broken(?)”
No. The grounding to Earth path should never be broken. In a perfect world, every grounding conductor and every metal component in the building will have a continuous path to Earth and back to the electrical source.
A main goal of grounding and bonding is to ensure equipotential between any two points, whether part of the electrical system or not. A break in continuity could result in a large potential during a fault.