400 Amp Electrical Service Upgrade in St. Louis
Professional 400 amp electrical service upgrade by First Choice Electric. Serving St. Louis County, St. Charles County, and surrounding areas with licensed electricians, permits included, and same-day inspection.
$4,500 - $8,000
installed400 Amp Electrical Service Upgrade Services in St. Louis
First Choice Electric provides professional 400 amp electrical service upgrade services throughout the St. Louis metropolitan area, serving 30+ communities with licensed electricians.
Service Overview
What's included
Whether you're in O'Fallon, St. Charles, St. Peters, or any of the communities we serve, our licensed electricians deliver code-compliant work with same-day inspection.
Permits
Included
Ameren Coord
Included
Timeline
1-2 Days
Inspection
Same-Day
Ready to Get Started?
Get a free, no-obligation quote for your 400 amp electrical service upgrade project.
Get Your Free QuoteWhy Choose First Choice Electric for Your 400 Amp Service
Professional service, transparent pricing, and quality work from St. Louis's trusted electrical contractor.
Maximum Capacity
Class 320 meter base with dual 200A panels for large homes and high-demand properties.
Multi-EV Ready
Support multiple Level 2 EV chargers, each drawing 40-80 amps continuously.
Large Home Power
Ideal for 4,000+ sq ft homes, multiple HVAC zones, pools, workshops, and full electrification.
Future-Proof
Accommodates future additions, solar systems, battery backup, and growing electrical demands.
Panel Brands We Install
We install quality electrical panels from trusted manufacturers. All panels meet current NEC codes and come with manufacturer warranties.
Panels That Need Immediate Replacement
These panel brands have documented safety issues and are no longer considered safe. If you have one of these panels, we strongly recommend replacement.
Federal Pacific
Breakers fail to trip during overloads, causing fires
Safety Warning
Zinsco
Breakers melt to bus bars, cannot be shut off
Safety Warning
Pushmatic
Breakers become unreliable with age, parts unavailable
Safety Warning
Challenger
Some models recalled for fire hazards
Safety WarningNot sure what panel you have? We offer free inspections to identify your panel brand and assess its condition.
Our 400 Amp Service Process
From first call to finished project, here's what to expect when you work with First Choice Electric.
Assessment & Estimate
We inspect your current panel, discuss your needs, and provide a detailed written estimate—no obligation.
Approval & Coordination
Once approved, we coordinate with Ameren to confirm scope of work and pull all required permits.
Scheduled Disconnect
We coordinate the temporary utility disconnect and schedule your installation date.
Install & Inspection
Our licensed electricians complete the work with same-day inspection, then contact the utility to restore power.
400 Amp Service Service Details
Service Size
400 Amps (320A cont.)
Configuration
Dual 200A panels
Meter Type
Class 320 meter base
Wire Size
500-600 kcmil aluminum
Permit
Included
Utility Coord
Ameren coordination included
What's Included in Your 400 Amp Service
Our quotes are comprehensive with no hidden fees. Here's everything included in your 400 amp service price:
400 Amp Service Service Areas
We provide 400 amp electrical service upgrade services throughout the St. Louis metro area.
Warren & Lincoln Counties
400 Amp Service FAQ
Common questions about 400 amp electrical service upgrade in St. Louis.
When do I need 400 amp service instead of 200 amp?+
400A service is typically needed for: homes over 4,000 sq ft, multiple EV chargers (2+), all-electric homes with heat pumps + electric water heaters, properties with pools/spas + workshops, or when load calculations exceed 200A capacity. We'll perform a load calculation during your free assessment.
How is 400 amp service configured?+
Most residential 400A service uses a Class 320 meter base feeding two separate 200-amp panels. This provides 60-80+ breaker spaces, more flexibility than a single panel, and is more cost-effective than true CT-metered 400A service.
Why is 400 amp service more expensive than 200 amp?+
400A service requires: a larger meter base (Class 320), heavier service entrance conductors (500-600 kcmil aluminum), two load centers instead of one, and more complex installation. The additional cost is typically $2,000-$4,000 more than a standard 200A upgrade.
Does Ameren Missouri support 400 amp residential service?+
Yes. Ameren requires 3-inch PVC conduit for 320A continuous service, clamp-jaw bypass meter sockets, and equipment from their approved list. We handle all Ameren coordination and ensure your installation meets their specifications.
Can I add 400 amp service to an existing home?+
Yes, though it's more involved than new construction. We'll need to upgrade your meter base, service entrance conductors, and install dual panels. In some cases, the utility may need to upgrade their transformer. We assess all requirements during the site visit.
Ready for Your 400 Amp Service?
Get a free quote for your 400 amp electrical service upgrade in St. Louis. First Choice Electric responds within 24 hours with transparent, no-obligation pricing.
Get Your Free QuoteInstallations by
First Choice Electric5377 State Highway N, Suite 437, Cottleville, MO 63304Missouri License #2025001688 | St. Charles County #E25-000008 | St. Louis County #ES4501