Three-phase service upgrade checklist

A three-phase service request is a utility coordination project. Load, voltage, transformer, metering, and schedule questions should be organized early.

Use this guide before requesting three-phase service so load need, voltage options, utility scope, metering, fault current, and schedule risks are clear.

When to use this guide

• A business needs three-phase service for motors, HVAC, industrial equipment, EV charging, process loads, or expansion.
• A utility asks for load lists, single-line diagrams, site plans, cut sheets, civil access notes, or demand data.
• A project may change transformer capacity, metering, service entrance, trenching, fault current, or phase balance.

Inputs to gather

• Existing service voltage, phase, utility account, meter arrangement, service location, transformer context, and drawings.
• Proposed load list with voltage, phase, kW/kVA, hp, starting current, duty cycle, future expansion, and schedule.
• Preferred and alternate voltage options, site plan, civil route, metering location, switchgear room, and outage constraints.
• Fault-current, SCCR/AIC, phase balance, motor starting, and power-quality concerns.

Project path matrix

Working checklist

• Confirm the project branch: A business needs three-phase service for motors, HVAC, industrial equipment, EV charging, process loads, or expansion.
• Measure or photograph the first hard inputs: Existing service voltage, phase, utility account, meter arrangement, service location, transformer context, and drawings. Proposed load list with voltage, phase, kW/kVA, hp, starting current, duty cycle, future expansion, and schedule.
• Record the decision basis: The utility may offer different voltage or service options than an equipment vendor assumes. Use voltage labels such as 120/208 V, 347/600 V, or 600 V only as discussion inputs until utility/design review confirms them.
• Keep the handoff package together: Load list, single-line, site plan, cut sheets, demand data, and project schedule.
• Stop before work proceeds if this applies: Fault-current rating, utility transformer, metering, service entrance, or civil route information is unknown.

Workflow

1. Confirm why three-phase is needed before requesting a specific voltage or service size.
2. Prepare load list, single-line, site plan, cut sheets, and schedule before utility review.
3. Separate utility-side scope from customer-side service entrance, switchgear, metering, and inspection work.
4. Review available fault current, equipment ratings, motor starting, phase balance, and power quality.
5. Track quotation, deposits, material lead time, civil work, inspections, outage, and energization as schedule risks.

Decision checkpoints

• The utility may offer different voltage or service options than an equipment vendor assumes.
• A service upgrade can change available fault current and downstream equipment rating requirements.
• Utility connection and local electrical inspection are separate steps.
• Post-upgrade phase balance and power-quality checks can matter after equipment is assigned.

Canada-specific checks

• Use voltage labels such as 120/208 V, 347/600 V, or 600 V only as discussion inputs until utility/design review confirms them.
• Utility requirements vary by territory, service size, metering, civil scope, and customer class.
• This guide does not approve service voltage, transformer capacity, metering, fault-current ratings, service entrance work, or utility connection.

Project package to keep

• Load list, single-line, site plan, cut sheets, demand data, and project schedule.
• Existing service photos, metering photos, account context, and civil route notes.
• kW/kVA/amps, phase-balance, and fault-current screening outputs.
• Utility quotation, design comments, inspection notes, outage plan, and energization records.

Stop and get local review

• Fault-current rating, utility transformer, metering, service entrance, or civil route information is unknown.
• The project depends on a voltage the utility has not confirmed.
• Large motor starting, VFDs, harmonics, or sensitive loads may affect utility or facility power quality.

Questions to settle before work starts

• Which local authority, utility, property authority, product listing, or manufacturer instruction controls this commercial and industrial loads decision?
• Which inputs are measured from the field or nameplate, and which are still assumptions from a quote, drawing, or memory?
• Which part of the work will be concealed, energized, interconnected, or purchased before review if the sequence is not controlled?
• Which single assumption would change the equipment choice, installation path, cost, schedule, or inspection timing?
• Who will keep the final photos, calculator outputs, product documents, permit or utility records, and commissioning notes?

Use the related tools

• Use the Voltage Systems Chart for voltage terminology.
• Use the kW, kVA, and Amps Calculator to normalize proposed loads.
• Use the Transformer Short-Circuit Current Calculator when fault-current changes need screening.

Public reference starting points

• Hydro One service upgrade - Utility service-upgrade workflow example.
• BC Hydro power quality reference guide - Utility context for power-quality concerns.

Local standards and authority note

Confirm service voltage, metering, transformer, fault-current, and utility requirements with current utility documents and qualified professionals.