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Oak Hill 400A Panel Upgrade

A complete electrical service upgrade for a 3,800 sq ft residence — replacing an outdated 100A fuse box with a modern 400A breaker panel.
  • (Project Overview)

From an Outdated Fuse Box to a Modern 400A System

The Oak Hill residence had been running on a 1980s-era 100A fuse box that was no longer adequate for the household’s electrical demands. Repeated tripped breakers, lights flickering during appliance use, and the homeowner’s plans to add a home office and EV charger made an upgrade unavoidable.
Fixvolt was brought in to assess the situation and deliver a complete service upgrade — new 400A panel, updated grounding and bonding, a dedicated EV circuit in the garage, and 12 additional branch circuits to support the expanded load requirements. All work was permitted, inspected, and signed off within 48 hours.
The Challenge
Overloaded 50-Year-Old Infrastructure
The original 100A fuse box was undersized for the home’s current load, frequently tripping under normal usage. No capacity existed for an EV charger or home office circuit, and the grounding system was non-compliant with modern code.
Our Solution
Full 400A Upgrade With 12 New Circuits
We replaced the panel entirely, upgraded the meter base to accept 200A service, ran 12 new branch circuits, installed a dedicated 240V EV circuit, and brought the grounding system up to current NEC standards.
Project Details
Client
Oak Hill Residence
Location
Oak Hill, Near State
Service Type
Panel Upgrade
Property
Residential · 3,800 sq ft
Duration
2 Days
Completed
March 2024
Permit
Obtained & Passed
Status
  • Complete
  • (Full Breakdown)

Complete Scope of Work

Every item in the scope was agreed upon upfront in a written quote. No surprises, no additions billed without approval.

01

Main Panel Replacement

Full removal of the 100A fuse board and installation of a commercial-grade 400A three-phase main service panel with 48 circuit positions.

  • Siemens 400A main breaker panel
  • 48-circuit 3-phase distribution
  • Full surge protection device
  • AFCI breakers on all circuits
02

Sub-Panel Installation

Two dedicated 200A sub-panels installed per floor zone for isolated, individually protected distribution across all areas of the building.

  • 2× 200A sub-panels per zone
  • Colour-coded circuit labelling
  • Tamper-resistant enclosures
  • Isolated IT & general circuits
03

Smart Load Monitoring

Integrated real-time load monitoring system with mobile dashboard, automatic alerts, and intelligent load-shedding on non-critical circuits during peak demand.

  • Real-time energy dashboard
  • SMS & email overload alerts
  • Auto load-shedding logic
  • Historical usage reporting
04

EV Charger Pre-Wiring

Four dedicated 50A circuits and conduit runs installed to the basement car park, ready for Level 2 EV charger connection without further structural work.

  • 4× dedicated 50A circuits
  • Conduit to basement level
  • Weatherproof junction boxes
  • NEMA 14-50 outlets installed
05

Safety & Compliance

Complete arc-fault and ground-fault protection, bonding and earthing upgrade to current NEC 2023 standards, and full compliance documentation issued.

  • NEC 2023 full compliance
  • Earthing system upgrade
  • Bonding of all metalwork
  • Written compliance certificate
06

Testing & Commissioning

Full circuit-by-circuit load testing under live conditions, insulation resistance testing on all new wiring, and witnessed commissioning with the building manager before sign-off.

  • Load testing under full draw
  • Insulation resistance check
  • Witnessed commissioning
  • Written test report issued
  • (Transformation)

Before & After

From an outdated 100A setup to a modern 400A system. Safer, more stable, and ready for future use.
Original 100A Fuse Board — 1983
  • 100A single-phase capacity — critically undersized for modern office load
  • Rewired fuses — serious fire risk identified during safety audit
  • No arc-fault protection, no surge protection, no smart monitoring
  • Zero capacity for EV chargers or future expansion — no headroom
New 400A Smart Panel System — 2024
  • 400A 3-phase panel with 48 circuits and higher capacity
  • AFCI breakers on every circuit — all fire safety defects fully resolved
  • Smart load monitoring with real-time alerts and protection
  • Pre-wired EV circuits with room for future expansion
  • (Key Performance Metrics)

Before → After: The Numbers Tell the Story

The upgrade didn’t just solve the immediate problem — it future-proofed the home’s system for 30+ years, with improvements in capacity, safety, and energy management.

400A

Service capacity (was 100A)
  • +300% capacity
12+
New circuits added
  • Fully loaded

0

Call-backs post-completion
  • Zero defects
2d
Total project duration
  • 1 day ahead of estimate
“The team was professional and efficient. They explained every step of the upgrade process and left the workspace spotless. Our home now feels much safer, and we’ve had zero electrical issues since.”

— Sarah M., Manchester

  • (Contact)

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