Pearl Street Office: 3-Phase Service & EV Network
A 12,000 sq ft office building needed to support EV charging and prepare for solar. We delivered a 400A three-phase service upgrade with 6 networked ChargePoint chargers.
The Project
Challenge: 1985-built office with 200A single-phase service. Building wanted EV charging for employees and clients, plus future solar capacity.
Solution: 400A three-phase service upgrade, main distribution panel, 6× Level 2 EV chargers with load-balancing, and solar-ready infrastructure.
Specifications
- Service: 200A 1-phase → 400A 3-phase (PSCo transformer)
- Main Panel: Square D 400A with space for solar inverter
- EV Network: 6× ChargePoint CT4025 (30A each, networked)
- Load Control: Smart relay system prevents simultaneous peak demand
- Solar Ready: 50 kW rooftop capacity engineered and permitted
- Timeline: Design (2 weeks), permitting (4 weeks), installation (2 weeks)
Results
- 6 EV chargers operational, averaging 10 charges/week per site
- Building attracts EV-driving talent and eco-conscious clients
- Load-balancing prevents utility demand charges
- Solar Phase 2 can deploy within 4 weeks with no additional electrical work
- Project cost: $45,000 (service + electrical + chargers + labor + permits)
Technical Approach
Three-phase service provides 208V 3-phase (typical for commercial) plus 120V single-phase for standard loads. We calculated peak demand accounting for HVAC, lighting, and potential simultaneous EV charging. A load-analysis showed that without controls, 4+ chargers starting simultaneously would trigger demand charges. We implemented smart relays that stagger charger startup based on real-time building consumption, keeping peak demand flat.
For solar readiness, we pre-mounted inverter disconnect switches and conduit to the roof. When the client approves Phase 2 solar, electrical work takes days rather than weeks.
References
- Public Service Company of Colorado — Three-phase interconnection
- ChargePoint Network — Charger documentation and integration
- NEC Article 220 — Demand calculations
- City of Boulder — Commercial electrical permits
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