Master electrician guide to installing a meter base

Plan the Location Before You Pull Tools

Meter base placement is the first thing the AHJ and POCO will check. Get it wrong and you are pulling the whole assembly off the wall. Confirm the utility's service point requirements before you drill a single hole. Most POCOs publish a service manual with approved meter heights, clearance envelopes, and approved equipment lists. Read it.

NEC 230.70(A)(1) requires the service disconnect to be at a readily accessible location, either outside the building or inside nearest the point of entrance of the service conductors. For residential meter/main combos, coordinate the disconnect location with 230.85 emergency disconnect requirements, which mandate an outside, readily accessible disconnect marked per the 2020 and later cycles.

• Meter center height: typically 4 ft to 6 ft to the center of the meter, confirm with POCO.
• Working space per NEC 110.26: 36 in depth, 30 in width, 6 ft 6 in headroom.
• Keep clear of windows that open, gas meters (3 ft minimum per most POCO rules), and HVAC condensate lines.
• Verify the drip loop and service drop clearances per NEC 230.24.

Size the Service and Select the Base

Run the load calc per NEC Article 220 before you pick a can. A 200 A meter main is the default for most single-family dwellings, but do not assume. Heat pumps, EV chargers, and tankless electric water heaters push loads past 200 A fast. If the calc lands above 200 A, jump to 320/400 A class equipment and size the service conductors off NEC 310.12 for dwellings or Table 310.16 for everything else.

Match the meter socket to the POCO's approved list. Ringless, lever bypass, horn bypass, 4-jaw versus 5-jaw for 120/240 single phase versus network... all POCO specific. A base that passes inspection in one territory will get red-tagged in the next county over.

Tip from the field: photograph the POCO sticker inside the old meter can before demo. The stock number tells you exactly what the utility accepted last time, which saves an hour on the phone with the service planner.

Mounting and Weatherproofing

Mount to structure, not siding. Hit studs or use a proper backer board rated for the weight of the meter main plus the service conductors. Stainless or hot-dip galvanized fasteners only. Drywall screws and deck screws will rust through and leave the can hanging in five years.

Every penetration is a water path. NEC 230.52 requires service cables entering from the top or sides to be protected from physical damage and weather. Use listed hub fittings on the top knockouts, not just a locknut and bushing. Seal the wall penetration behind the can with a listed sealant, and make sure the flashing laps correctly over the top of the enclosure.

1. Level the can in both axes before you tighten the lags. A crooked meter reads fine but fails visual inspection every time.
2. Torque lags to the backer board spec, not gorilla tight.
3. Install the hub before you run conduit, thread sealant on the hub threads, not the conduit threads.
4. Caulk the top and sides of the flange against the wall. Leave the bottom open so any water that gets in can weep out.

Bonding, Grounding, and the Neutral

The meter base is on the line side of the service disconnect, so the neutral and the enclosure are bonded here and stay bonded through the service equipment. NEC 250.24(A) and 250.24(B) cover the grounded conductor and main bonding jumper. If the meter base and the service disconnect are separate enclosures, a neutral to enclosure bond is required at both if the POCO requires it, or only at the service disconnect per 250.24(A)(5). Check local amendments.

Grounding electrode conductor lands per NEC 250.64 and 250.66. For a 200 A service with copper service conductors, a #4 copper GEC to the ground rod and a #4 to the water pipe within 5 ft of entry is standard. Two rods 6 ft apart unless you have tested 25 ohms or less on one. Do not skip the supplemental electrode at the water line per 250.52(A)(1) if metallic water piping is present.

Tip from the field: run the GEC through the meter base only if the POCO permits it and the can has a listed lug. Otherwise land it in the service disconnect. A splice in the GEC must be irreversible per 250.64(C).

Service Conductors and Terminations

Strip, clean, and apply antioxidant on aluminum. Torque every lug to the label value with a calibrated torque wrench or torque screwdriver per NEC 110.14(D). Eyeballing lug torque is the number one cause of meter base failures in the first year. A loose connection at 200 A will arc, carbonize, and burn the base off the wall.

Dress the conductors with enough slack for the POCO to pull and reseat the meter. Do not coil excess conductor inside the can, it traps heat. Sweep the conduit so the conductors enter the lugs straight, no side loading on the terminals.

• Torque values are on the label inside the can, use them.
• Use listed antioxidant on aluminum, never on copper.
• Leave 12 to 18 in of free conductor for the POCO to work with.
• Phase tape the ungrounded conductors before the meter is set.

Inspection and Energization

Before you call for inspection, verify the labeling per NEC 230.85 (emergency disconnect), 110.24 (available fault current), and 408.4 where applicable. The emergency disconnect label must read "EMERGENCY DISCONNECT, SERVICE DISCONNECT" in the exact language of the code cycle your jurisdiction has adopted. Available fault current and the date of calculation go on a field-applied label that survives the environment.

Meg the service conductors before the POCO energizes. A 1000 V insulation test between phases and phase to ground catches nicked insulation and bad terminations before you put the utility's transformer at risk. Document the readings, the AHJ may ask.