Beginner's guide to installing a meter base

Before you touch the meter socket

Call the utility. Every POCO has its own spec sheet for meter base height, conductor type, grounding, and sealing. NEC 230.66 covers service equipment marking, but your utility's green book overrides anything ambiguous. Get the cut sheet, read it, then order the can.

Confirm the service size with the calculated load per NEC Article 220. A 200A residential service is standard, but a shop with a welder or EV charger may push you to 320/400A class. Undersizing the base means pulling it out in two years.

Pull the permit before you cut siding. Most AHJs want a rough-in inspection before the utility energizes, and the meter base location is part of that sign-off.

Mounting height and location

Utility rules typically set the center of the meter between 48 and 72 inches above finished grade. Verify with the POCO, not the internet. Keep the base accessible, out of walkways, and clear of gas meters per local gas utility clearance (often 36 inches minimum).

Working space in front of the meter and any adjacent service disconnect must meet NEC 110.26. That means 36 inches of depth, 30 inches of width or the width of the equipment (whichever is greater), and 6.5 feet of headroom. Do not mount above a deck rail or behind landscaping that will grow in.

Field tip: if the wall is vinyl siding, install a mounting block sized to the base before you hang the can. Trying to caulk around siding J-channel after the fact is a callback waiting to happen.

Conductor sizing and entry

Service entrance conductors are sized from NEC Table 310.12 for dwelling services, or Table 310.16 for everything else. For a 200A dwelling, 2/0 copper or 4/0 aluminum SER/SEU is the common pick. Check the meter base label for its conductor range before you cut.

Top-feed bases get a weatherhead and drip loop per NEC 230.54. Bottom-feed or lateral services land in a raintight hub or through a threaded boss with sealing locknuts. Use listed reducing washers if the KO is oversized, and do not rely on a plastic bushing as your bonding means.

• Keep conductor length inside the can minimal, but leave enough slack to land the lugs cleanly.
• Torque lugs to the value stamped on the base, typically 250 to 375 in-lb for 2/0 to 4/0. Use a calibrated torque screwdriver or wrench per NEC 110.14(D).
• Anti-oxidant compound on aluminum, every time.
• Mark the grounded (neutral) conductor with white tape or paint at every accessible point per NEC 200.6.

Bonding, grounding, and the neutral

The meter base is on the line side of the service disconnect, so the neutral and enclosure are bonded together here. Do not install an isolating kit in a meter base unless the utility specifies one for a paralleled service. The grounded conductor carries fault current back to the transformer on the line side, which is why NEC 250.24(C) requires it to be run to the service equipment regardless of whether the load needs a neutral.

Grounding electrode conductor can land in the meter base, in the service disconnect, or in a separately mounted tap box, depending on the POCO. NEC 250.64(C) allows an unspliced run, or an irreversible splice like an exothermic weld or listed compression connector. Size the GEC from Table 250.66.

Drive two ground rods, 6 feet apart minimum, unless a single rod tests at 25 ohms or less per NEC 250.53(A)(2). Nobody tests one rod. Drive two and move on.

Sealing, weatherproofing, and the ring

Every hole in the back of the can is a water path. Use listed weatherproof hubs on top entries, duct seal on conductor openings, and silicone on the mounting flange where it meets siding. A can full of water in January will freeze, crack the jaw base, and take the main breaker with it.

Leave the meter socket ring loose for the utility. They set the meter, install their seal, and lock it. Do not cut a utility seal to rework anything, call them for a disconnect. Cutting a seal is a fine in most jurisdictions and an automatic red tag.

Field tip: if you are in a coastal or high-humidity area, spec a stainless or powder-coated base. A painted steel can on a salt-air install will show rust bleed through the seams inside of a year.

Final checks before the utility arrives

Walk the install before you call for inspection. Verify torque, verify bonding, verify the GEC is continuous and sized right. Megger the service conductors if you have any doubt about damage during the pull.

Label the service disconnect with voltage, phase, available fault current, and the date the fault current was calculated per NEC 110.24. The sticker is cheap. The violation is not.

1. Meter base level and square to the wall.
2. Conductors landed, torqued, and marked.
3. Neutral bonded, GEC landed and continuous to the electrode system.
4. All penetrations sealed, hub gaskets seated.
5. Dead front and cover installed, ring loose for the POCO.
6. Permit card posted, inspection scheduled.

Get the green tag, get the meter set, move to the next job.