NEC Article 250 — Grounding and Bonding for NJ Residential Services
How NJ residential services are grounded and bonded per NEC 250: ground rods, water main bonds, GEC sizing, and the neutral-to-ground bond at the service disconnect.
Article 250 is the most-failed inspection item on residential electrical work in NJ. Get the grounding and bonding right and you'll never fail rough-in. The basics:
The Grounding Electrode System (NEC 250.50) for a typical NJ residential service consists of two ground rods (driven 6 ft apart) AND the metal underground water-pipe (the first 5 ft of metal water service entering the building). Both must be connected to the service disconnect with a Grounding Electrode Conductor (GEC). For services 200A or smaller, the GEC is typically #4 AWG copper bare or insulated.
The neutral-to-ground bond happens ONLY ONCE — at the first means of disconnect, which on a typical residential service is the main breaker in the main panel. Sub-panels downstream are FOUR-WIRE (hot-hot-neutral-ground) with the neutral bar isolated from the panel can. Bonding the neutral at a sub-panel creates a parallel path and is the most common AHJ rejection.
GEC sizing per NEC 250.66: for a 200A service with 4/0 AL service-entrance conductors, the GEC is #4 AWG CU. For a 100A service with 2 AWG CU service entrance, the GEC is #8 AWG CU. NEC Table 250.66 has the full matrix.
Bonding metal water pipe per 250.104(A): the metal water-piping system (cold-water side, typically) must be bonded to the service disconnect with a conductor sized per Table 250.66 — typically the same gauge as the GEC. This bond can be made at the water main, the water heater, or any accessible point in the system, but must be where the connection is most likely to remain electrically continuous.
The classic Hudson County rejection: GEC connecting only to a single ground rod with no water-main bond. Two ground rods OR rod + water main are required when the rod-only resistance can't be verified at 25 Ω. Inspectors don't measure resistance; they require the supplemental rod or water bond by default.
For permit submittals, every Malfettone Electric panel-upgrade SLD shows the GEC routing explicitly. The free single-line diagram tool at /tools/single-line-diagram includes a grounding-electrode call-out on the panel-upgrade template.
Related guides
This guide is an educational summary written by a licensed NJ master electrician. It is not a substitute for the National Electrical Code or for the judgment of your local AHJ. For real permit work, verify every code interpretation with your authority having jurisdiction and a licensed electrician of record.