To wire the load side of a standard 200-amp residential meter box to the main service panel, use 4/0 AWG aluminum (or 2/0 AWG copper) XHHW-2 or THWN-2 service entrance conductors. The black and red hot wires land on the Load L1 and Load L2 terminals, the white neutral lands on the isolated neutral busbar, and the meter enclosure itself is grounded via a bare #4 AWG copper wire to a dedicated ground lug. The utility handles the line side; your scope begins at the load terminals and ends at the main panel's main breaker.
⚠️ CRITICAL MAINS SAFETY & UTILITY WARNING
Wiring a meter socket involves the service entrance. The utility drop (line side) is ALWAYS LIVE and has no upstream breaker to protect you. Never attempt to terminate, pull, or disturb the line-side conductors or the utility meter itself. Before working on the load side, ensure the main breaker in the downstream panel is OFF. Verify the load-side bus is dead using a Category III or IV multimeter tested on a known live source first. Local codes and utility company regulations almost universally require a licensed electrician to perform service entrance work and pull permits. This guide is for educational preparation and AHJ inspection readiness.
Tools and Materials for a 200A Load-Side Run
Service entrance work leaves zero margin for error. Undersized wire or under-torqued lugs will cause thermal failure under continuous load. Gather the following before opening the enclosure:
- Conductors: 4/0 AWG Aluminum XHHW-2 (Black, Red, White) or 2/0 AWG Copper THWN-2. Assumed 75°C termination rating per NEC 110.14(C).
- Grounding: #4 AWG Bare Copper wire for the meter enclosure equipment grounding conductor (EGC).
- Conduit & Fittings: 2-inch PVC Schedule 80 or Rigid Metal Conduit (RMC) with insulated grounding bushings if using metallic conduit.
- Torque Tool: Calibrated digital torque screwdriver capable of measuring up to 300 inch-pounds (in-lbs). NEC 110.14(D) mandates calibrated tools for terminations.
- Wire Prep: Heavy-duty cable strippers (e.g., Klein Tools Katapult or a dedicated 4/0 stripping tool), wire brush, and anti-oxidant compound (Noalox) for aluminum.
- Testing: CAT III/IV Digital Multimeter and a continuity tester.
Wire Sizing and Torque Specifications
The NFPA National Electrical Code (specifically NEC 310.12) dictates minimum service entrance conductor sizing. Always defer to the manufacturer's torque sticker inside the meter socket, but use this table as your baseline for a 200A residential service:
| Parameter | Aluminum (Standard) | Copper (Upgrade) |
|---|---|---|
| Minimum AWG Size (200A) | 4/0 AWG | 2/0 AWG |
| Typical Lug Torque | 250 in-lbs | 250 in-lbs |
| Strip Length | 1-1/4 inches | 1-1/4 inches |
| Anti-Oxidant Required? | Yes (Noalox) | No |
Step-by-Step: Wiring the Meter Box Load Terminals
Assuming the meter socket is physically mounted, the conduit is run to the main panel, and the utility has not yet dropped the line-side wires, follow this sequence to terminate the load side.
- Prep the Aluminum Conductors: Strip exactly 1-1/4 inches of insulation from the black, red, and white 4/0 AWG wires. Use a wire brush to clean the exposed aluminum strands, then immediately coat them with an anti-oxidant compound to prevent galvanic corrosion and high-resistance heating over time.
- Land the White Neutral: Insert the stripped end of the white 4/0 AWG neutral conductor into the load-side neutral busbar lug. Ensure no bare strand is exposed outside the lug barrel and no insulation is pushed inside the barrel. Tighten the set screw with your calibrated torque screwdriver to the manufacturer's spec (typically 250 in-lbs). The neutral bar in a meter socket is isolated from the enclosure; do not bond it here.
- Land the Black and Red Hots: Insert the black 4/0 AWG conductor into the Load L1 terminal and the red 4/0 AWG conductor into the Load L2 terminal. Torque both to 250 in-lbs. Give each wire a firm, sharp tug to verify mechanical retention.
- Bond the Enclosure (Ground): The meter socket metal enclosure must be grounded. Take the bare #4 AWG copper grounding conductor, terminate one end to the dedicated equipment grounding lug inside the meter socket, and route the other end to the main panel's ground busbar. Torque the meter socket ground lug to its specific rating (usually 40-50 in-lbs for #4 AWG).
- Secure and Dress the Wires: Use heavy-duty cable ties or conduit straps inside the enclosure to dress the 4/0 AWG wires neatly, ensuring they do not press against the meter glass ring or interfere with the meter insertion blades.
Verification and Pre-Energization Testing
Never signal the utility to energize the service without performing a dead-front verification. Since the line side is not yet live, you are testing for faults, not voltage.
- Visual Torque Check: Inspect every lug. Many modern torque screwdrivers leave a physical mark, or you can use a torque-seal marker pen across the screw head and lug to prove to the AHJ inspector that the terminal was torqued to spec.
- Short Circuit Test: Set your multimeter to continuity or Ohms (Ω). Place one probe on the Load L1 (black) lug and the other on the Neutral (white) busbar. You must read 'OL' (Open Loop). Repeat for Load L2 (red) to Neutral. If you read < 1 ohm, you have a dead short in your conduit run or panel. Do not proceed.
- Ground Continuity Test: Measure between the meter enclosure metal housing and the bare ground wire. You should read < 1 ohm, confirming the enclosure is properly bonded to the grounding electrode system via the main panel.
The Most Common Botch: False Bonding and Loose Neutrals
The most frequent and dangerous mistake DIYers make when wiring a meter box is creating a false neutral-to-ground bond. According to EC&M Service Entrance Requirements, the neutral and ground must ONLY be bonded at the first point of disconnect (the main service panel). If you install a bonding screw or jumper in the meter socket, neutral return current will split and travel back to the transformer via the bare ground wire, your plumbing, and your cable coax. Symptom: You will measure stray AC voltage (2V to 10V) on water pipes, experience flickering lights, and eventually melt the ground lug due to continuous neutral current overload.
The second most common botch is failing to use anti-oxidant paste on aluminum wire. Symptom: Two years post-installation, the neutral lug overheats, melts the insulation, and causes a phase imbalance that destroys 120V appliances in the home.
Frequently Asked Questions
What size wire do I need for a 200 amp meter box?
For a standard 200-amp residential service, NEC 310.12(A) requires a minimum of 4/0 AWG aluminum or 2/0 AWG copper for the hot and neutral conductors. The equipment grounding conductor (EGC) for the meter enclosure itself must be a minimum of #4 AWG copper or #2 AWG aluminum. Always verify local AHJ amendments, as some jurisdictions require 250 kcmil aluminum for 200A services to account for voltage drop on long runs.
Where does the ground wire connect in a meter socket?
The bare equipment grounding wire connects to a dedicated, small grounding lug bonded directly to the metal backplane of the meter socket enclosure. It does not connect to the main neutral busbar. The neutral bar in a meter socket is isolated (floating) from the metal box. The ground wire's sole job is to clear faults on the metal enclosure itself, not to carry neutral return current.
Can I wire the line side of the meter box myself?
No. The line side (the top terminals where the utility drop connects) is strictly the property and jurisdiction of the local power utility. Tampering with the line side, breaking the utility seal, or attempting to terminate the service drop yourself is illegal in almost all jurisdictions, carries a massive risk of fatal arc flash, and will result in the utility refusing to energize your panel. Your legal and physical scope of work stops at the load-side terminals.
