Electrical Service Upgrade Engineer Letter — 200A Panel and Meter Main

A service upgrade — from a 100A or 150A panel to 200A or larger — is one of the few electrical projects that almost always requires both a rough-in and a final inspection, because it touches the service entrance, the grounding electrode system, and the bonding of the entire premises. When the final is missed or the permit lapses, the utility has already energized the new service, drywall has gone back up, and the closeout becomes a PE job.

What the letter covers

Service entrance. The conductor size (typically 2/0 or 4/0 aluminum SE for 200A residential), insulation rating, routing, and physical protection per NEC Article 230.

Meter main and disconnect. Location per utility requirements, labeling, working clearance per NEC 110.26, and overall NEC Article 230 Part VI compliance.

Service panel. AIC rating, grounding and bonding per Article 250, main bonding jumper, GEC size, and interior panel bonding.

Grounding electrode system. Ground rods (two at 6 ft apart minimum for supplemental electrodes), the concrete-encased electrode (Ufer) if available, the water service bond, and the bonding of structural metal. The GES is documented per NEC 250.52 and 250.66.

Branch circuits. Verified against the panel schedule and nameplate. Any added circuits from the upgrade are individually traced and verified.

Surge protection. For residences under NEC 2020 and later, Type 1 or Type 2 SPD is required at the service panel.

Load calculation. The upgraded panel’s capacity is verified against a full demand load calculation per Article 220, confirming it does not exceed 80% of the service ampacity for continuous loads.

Why service upgrades drive permit closure issues

Three common scenarios:

A homeowner added EV charging, solar, or a heat pump and had to upgrade the service. The electrician did the work, the utility energized it, but the permit closeout lagged. Now the homeowner is selling.

The prior owner upgraded the service 5+ years ago and the permit shows open in the county records. The buyer’s closing attorney flags it.

The service was upgraded as part of a larger renovation, the larger permit closed, but the subordinate electrical permit for the service upgrade was never finaled.

What we need from you

The permit application, the panel schedule, the utility cut-in date (if available), the panel manufacturer and model, and access for the site visit. With that package, most service upgrade letters close in 24–48 hours.

For the related scenario of rough-in electrical inspections that were missed, see our rough-in electrical inspection guide.