The standard residential 200A meter socket wiring diagram routes two hot legs and a neutral from the utility drop through the meter jaws to the load lugs, feeding the main disconnect panel. The equipment grounding conductor bypasses the meter entirely, and the neutral-to-ground bond occurs only at the first point of disconnect. For a standard 200A service under 100 feet, the concrete default is a Milbank 4828 ring-type meter socket wired with 4/0 AWG Aluminum XHHW-2 conductors.

SAFETY WARNING: The line-side jaws of a meter socket are energized by the utility the moment the drop is connected. You cannot de-energize these jaws with a breaker. All customer-side wiring (load lugs to panel) must be completed, torqued, and verified with a multimeter before the utility installs the meter and applies the seal. Local codes and utility rules often require a licensed electrician to pull the permit and perform the final termination.

Terminal Mapping and Symbol Translation

Reading a meter socket wiring diagram requires translating schematic symbols to the physical brass and aluminum hardware inside the enclosure. The most critical distinction is between the jaws (utility side, unmetered, no customer access once sealed) and the lugs (customer side, load-bearing, where your service entrance conductors terminate).

Diagram Symbol / Label Physical Hardware Function & Connection Point
Line Jaws (Top) Spring-loaded brass contacts Receive utility drop wires (Line 1, Line 2, Neutral). Do not touch.
Load Lugs (Bottom) Mechanical set-screw lugs Terminate customer service entrance conductors feeding the main panel.
Neutral Bus (Center) Insulated aluminum bar Carries return current. Isolated from the socket enclosure.
Ground Lug (Enclosure) Screw terminal on metal box Terminates Grounding Electrode Conductor (GEC) from ground rods.
Meter Stab Symbols Blade receptacles on meter Bridge the Line jaws to the Load lugs when the meter is inserted.

In standard single-line diagrams, the neutral bus is drawn as a solid horizontal line intersecting the vertical hot phases. The ground symbol (three decreasing horizontal lines) points strictly to the enclosure ground lug, never to the neutral bus. In a standard meter-only socket, neutral and ground are strictly isolated. Bonding them here creates a parallel neutral path, violating NEC 250.24(A)(5) and creating a severe shock hazard.

Node-by-Node Trace: Utility Drop to Main Panel

Follow this physical path to understand how current flows and where the grounding boundary lies. This trace assumes a standard overhead utility drop feeding a Milbank 4828 socket, which then feeds an exterior main breaker panel.

  1. Utility Drop to Line Jaws: The utility's triplex cable (two insulated hot legs, one bare neutral) enters through the top hub. The hots land on the top left and top right spring jaws. The bare neutral lands on the center neutral jaw.
  2. The Meter Bridge: When the utility slides the glass meter into the ring, its four copper stabs push into the jaws. The top stabs grab the line voltage; the bottom stabs push it out to the load side. The center stab bridges the neutral jaw to the neutral bus.
  3. Load Lugs to Feeder: Your customer-owned service entrance conductors (two hots, one neutral) are terminated in the bottom mechanical lugs. These lugs are physically bolted to the bottom jaws, completing the circuit.
  4. Feeder to Main Disconnect: The three conductors exit the bottom hub and enter the main breaker panel. The two hots land on the main breaker lugs. The neutral lands on the panel's neutral bus.
  5. The Grounding Path: A separate Grounding Electrode Conductor (typically 4 AWG bare copper) runs from your ground rods, enters the meter socket, and lands on the enclosure ground lug. A second ground wire runs from the socket enclosure to the main panel's ground bus. Inside the main panel, the neutral bus and ground bus are bonded together via the main bonding jumper. This is the only place the bond occurs.

Sizing Decision Tree: Wire, Lugs, and Conduit

Selecting the correct wire gauge for the meter-to-panel run depends on your service amperage, conductor material, and run length. Milbank's technical specifications for standard 200A sockets dictate using conductors rated for 75°C terminations. While NEC Table 310.16 lists 4/0 Aluminum at 180A, NEC 310.12 explicitly permits 4/0 Aluminum for 200A residential services.

Scenario Criteria Hot & Neutral Wire Size Conduit Size (PVC Sch 80) Terminal Torque Spec
200A Service, Run < 100 ft 4/0 AWG Aluminum XHHW-2 2 inch 250 in-lbs (21 ft-lbs)
200A Service, Run > 100 ft (>3% V-drop) 250 kcmil Aluminum XHHW-2 2.5 inch 300 in-lbs (25 ft-lbs)
200A Service, Copper Preference 2 AWG Copper THHN/THWN-2 1.5 inch 180 in-lbs (15 ft-lbs)
Grounding Electrode Conductor (GEC) 4 AWG Bare Copper (min) N/A (run in PVC or direct) 120 in-lbs (10 ft-lbs)
The Default Pick: Stop guessing. For 90% of standard residential new builds or upgrades, buy a Milbank 4828 meter socket, pull 4/0 AWG Aluminum XHHW-2 (black, black, white) for the hots and neutral, and use a 4 AWG bare copper wire for the ground rod connection. Run it in 2-inch Schedule 80 PVC to protect against physical damage and UV degradation. Terminate it in a Siemens W0408ML1125 200A main breaker panel.

Verification Protocol: Testing Before the Utility Seals

Never assume the wiring is correct just because it looks tight. Before the utility installs the meter, you must perform dead-testing with a multimeter to ensure no short circuits or improper bonds exist.

  1. Visual Torque Check: Using a calibrated inch-pound torque screwdriver or torque wrench, verify every mechanical lug is tightened to the manufacturer's spec (typically 250 in-lbs for 4/0 AL). Apply a line of pink TorqueSeal across the screw head and wire to provide a visual tamper and vibration indicator.
  2. Hot-to-Ground Continuity (Must be OPEN): Set your multimeter to continuity or Ohms. Place one probe on the Load Lug A (black wire) and the other on the socket enclosure. The meter must read 'OL' (Open Loop). Repeat for Load Lug B. If you read continuity, you have a nicked wire insulation or a ground fault in the panel.
  3. Neutral-to-Ground Isolation (Must be OPEN): Place one probe on the center Neutral Bus and the other on the socket enclosure ground lug. The meter must read 'OL'. If it reads continuity, you have illegally bonded the neutral to the ground inside the meter socket. The bond belongs only in the main disconnect panel.
  4. Hot-to-Neutral Continuity (Must be OPEN): Check across the load lugs and the neutral bus. It should read open. A reading of near-zero ohms means you have a dead short in your main panel wiring.

Once the utility installs the meter and energizes the drop, switch your multimeter to AC Volts. Measure Line A to Neutral (expect 120V ± 5%), Line B to Neutral (expect 120V ± 5%), and Line A to Line B (expect 240V ± 5%).

Common Wiring Mistakes and Code Caveats

The most frequent failure mode on jobsites is mixing up the utility side and the customer side. The utility drop wires never go under mechanical set-screws; they slide into the spring jaws. Forcing a utility neutral into a load-side mechanical lug will result in the utility inspector failing the job and refusing to drop the line.

Another critical error is failing to remove the green bonding screw or strap inside the downstream main breaker panel if the panel is being used as a subpanel rather than a main disconnect. However, for the panel immediately following the meter socket (the first point of disconnect), that bonding strap must remain installed to satisfy NEC 250.24.

Finally, pay attention to the bend radius of 4/0 Aluminum XHHW-2. It is a stiff cable. If you do not leave enough slack in the meter socket enclosure, the mechanical stress can pull the wire out of the lug over time as the metal expands and contracts with seasonal temperature swings. Strip exactly the length indicated by the lug manufacturer's strip gauge—usually about 1.25 inches—and ensure no bare copper/aluminum is exposed outside the lug barrel.