Toronto Hydro Connection Guide: From Application to Energization
Building in Toronto? Your electrical service connection goes through Toronto Hydro - and their process has specific requirements that differ from Hydro One and other Ontario LDCs. Here's the complete engineering guide based on Toronto Hydro's 2025 connection procedures.
Toronto Hydro Supply Offerings
Toronto Hydro determines your supply type based on load requirements, reliability needs, and geographic location. The utility makes this decision at its sole discretion.
| Supply Type | Voltage | Service Size | Typical Application |
|---|---|---|---|
| Overhead from road | 120/240V 1Φ | Up to 200A | Residential, small retail in overhead areas |
| Underground from road | 120/240V 1Φ or 120/208V 3Φ | Up to 400A | Residential, small commercial in underground areas |
| Pad-mount transformer | 120/208V or 347/600V 3Φ | Up to 3000A | Commercial, mid-rise, industrial - transformer on private property |
| Building vault transformer | 120/208V or 347/600V 3Φ | Up to 2500A (larger loads by TH review) | High-rise, large commercial - transformer inside building |
| Network supply | 120/208V or 347/600V 3Φ | Varies | Downtown Toronto core - high reliability grid network |
For residential 100 A to 200 A upgrades, the panel upgrade guide covers Toronto Hydro’s service upgrade request alongside the other Ontario utilities.
Pad-Mount vs. Vault Transformer
| Factor | Pad-Mount | Building Vault |
|---|---|---|
| Location | Outside on concrete pad, private property | Inside building, dedicated room |
| Ownership | Toronto Hydro owned & maintained | Toronto Hydro owned, building provides the room |
| Access | 24/7 unrestricted utility access required | 24/7 key access for TH crews |
| Clearances | 3m in front of doors, 2m from sides without doors, no overhead obstructions | Per TH vault room specifications (ventilation, drainage, fire rating) |
| Cost to customer | Capital contribution may apply | Customer builds the room to TH specs - significant construction cost |
| Best for | Low-rise commercial, plaza, industrial | High-rise, dense urban, no outdoor space |
10 Steps to Get Connected
Toronto Hydro's official connection process based on their 2025 Customer Connection Guide:
- 1. Submit Service Request - Online at torontohydro.com/servicerequest with site plan and load requirements
- 2. Toronto Hydro reviews - TH assesses grid capacity, determines supply type and required infrastructure
- 3. Offer to Connect issued - TH provides conditions, costs, and timeline
- 4. Accept offer & pay - Customer accepts conditions and pays capital contribution (if applicable)
- 5. TH designs infrastructure - Utility designs transformer, switchgear, and distribution
- 6. Customer installs equipment - Meter base, CT cabinet, main switchboard, grounding per CEC
- 7. ESA inspection - Electrical Safety Authority inspects customer equipment
- 8. TH installs transformer - Utility installs and connects their infrastructure
- 9. Meter installation - TH installs revenue metering (self-contained or CT type)
- 10. Energization - Service is connected and energized
Timeline: Service connections take a few weeks to several months depending on scope. Large developments with vault transformers or infrastructure upgrades can take considerably longer. Submit your Service Request as early as possible.
A pad-mount service from the street to the electrical room
A typical low-rise commercial supply, not a specific site. Underground ducts shown schematically.
Detail A: pad-mount clearances
Plan view; confirm on each project with Toronto Hydro
Parts
Underground supply from the road: Toronto Hydro decides the supply type (overhead, underground, pad-mount, vault or network) from load, reliability and location.
Property line: the pad-mount transformer sits on private property; all customer equipment must be within the limits Toronto Hydro defines, with access for maintenance.
Pad-mount transformer: Toronto Hydro owned and maintained, 120/208 V or 347/600 V 3-phase, up to 3000 A; 24/7 unrestricted utility access; a capital contribution may apply.
Service to the building: underground in ducts; call Ontario One Call at least 5 business days before excavating.
CT cabinet: installed by the customer; services over 200 A need CT metering equipment that meets Toronto Hydro’s metering requirements.
Revenue meter: Toronto Hydro installs it (self-contained or CT type) after the ESA inspection.
Main switchboard: installed by the customer and inspected by the ESA.
Grounding per the CEC, installed by the customer.
Order of work: the customer installs and the ESA inspects; then Toronto Hydro installs the transformer, then the meter, then energizes the service.
- Underground duct with cables
- Property line
- Utility owned or installed
- Customer installs
- Grounding
Key Toronto Hydro Requirements
| Requirement | Detail |
|---|---|
| Call before you dig | Ontario One Call (1-800-400-2255) minimum 5 business days before excavation - it's the law |
| Underground vs overhead | TH has both systems. Converting from overhead to underground requires TH approval and additional customer cost |
| Equipment placement | All customer equipment must be within TH-defined limits on your property with sufficient access for maintenance |
| Temporary disconnections | For renovations, panel changes, roofing - standard isolations need about two weeks to a month of lead time, depending on scope |
| Line covers | For cranes near powerlines - don't prevent electrocution, but draw attention to danger |
EV Charging Connection Procedures (EVCCP)
Toronto Hydro has a dedicated EV Charging Connection Procedure for projects installing Level 2 and DC fast chargers. Key points:
- Verify existing service capacity before adding EV chargers
- Large EV installations may require service upgrade or dedicated transformer
- TH's Load Capacity Map helps assess available grid capacity at your location
- A free, non-binding EV Preliminary Consultation Report (EVPCR) within 15 calendar days helps assess capacity before committing (NBEs cover non-EV requests)
Grid Modernization & Smart Grid
Toronto Hydro is implementing significant grid modernization initiatives relevant to developers:
- Dual radial automation - improved reliability with automatic switching
- 600V network modernization - downtown core network monitoring
- Non-Wires Alternatives - energy storage and demand response programs
- Vehicle-to-grid (V2G) - future bidirectional EV charging capabilities
Frequently Asked Questions
How long does a Toronto Hydro connection take?
Toronto Hydro says connections take a few weeks to several months: it contacts you within 10 business days, design and quote typically take up to 60 days once all information is received, and energization follows within about five business days (750 V or less). Start with a P.Eng load calculation and submit early.
What documents are required?
Site plan, single-line diagram, building permit, load calculations (a demand load summary per the OESC may be required; P.Eng-sealed where the project requires it), panel schedule, and, for services over 200A, CT metering equipment meeting Toronto Hydro's metering requirements. See our service entrance guide.
Does Toronto Hydro charge for connections?
Basic connection costs are covered by a standard allowance recovered through rates; work beyond it is charged at actual cost, and infrastructure expansions (new transformer, cable extensions) may require a capital contribution set by Toronto Hydro's economic evaluation, depending on scope.
