Electrical › Commercial contractors
Commercial Electrical Contractors in Toronto
Panel and service upgrades, dedicated circuits, lighting retrofits and ESA code corrections for commercial and industrial sites across the GTA. Scoped and project-managed by Cablify, performed by Licensed Electrical Contractors.
What actually gets called in
Nearly every commercial electrical job we get called for falls into one of five buckets. A tenancy has outgrown its service. Something sensitive needs its own circuit. The lighting is old and expensive to run. ESA has issued a defect notice. Or a new piece of equipment has arrived and there is nothing to plug it into.
The sections below cover each one properly, including the part most contractor pages skip: how to tell which one you actually have. For the broader picture, including fit-outs and comms room power, start at commercial electrical services.
Service and panel upgrades
A service upgrade is not really an electrical decision, it is a capacity decision. The question is what the building has to run in five years, not what tripped last week. We start with a load calculation to CEC Section 8 against your actual and planned equipment, then size from there.
| Service | Typically suits |
|---|---|
| 100A | Small retail unit, single office suite, light plug load |
| 200A | Standard commercial tenancy, small office, café or salon |
| 400A | Larger tenancy, light industrial, kitchen equipment, multiple HVAC units |
| 600A and above | Warehouse and industrial with machinery, EV charging banks, multi-tenant |
Voltage matters as much as amperage. Most GTA commercial units run 120/208V three-phase. Larger commercial and industrial buildings run 347/600V, with lighting fed at 347V. That is a Canadian configuration, so equipment specified from a US catalogue at 277/480V will not simply drop in. We check this before anything is ordered.
Signs the service is the problem
- No spare breaker spaces left, or breakers doubled up on one lug
- A fuse panel still in service
- Adding EV chargers, a rooftop unit, or production equipment
- Nuisance tripping that moves around rather than staying on one circuit
- A new tenant with a much heavier load than the last one
- Panel schedule that no longer matches what is on the breakers
Dedicated and isolated-ground circuits
A dedicated circuit means one breaker and one neutral serving one piece of equipment and nothing else. It is the fix for a server, a POS system, a medical device or a compressor that keeps dropping when something else on the circuit starts up.
Isolated ground is a different thing, and it is oversold. An IG receptacle runs an insulated ground conductor all the way back to the service ground instead of bonding to the box. It was worth doing when equipment was sensitive to ground noise. Modern switch-mode power supplies rarely care. We install it where a manufacturer specifies it and tell you when it is not buying you anything.
The shared neutral problem. Multi-wire branch circuits share one neutral across phases, which works fine for linear loads because the currents cancel. Computers, LED drivers and UPS units are non-linear, and their third-harmonic currents add on the neutral instead of cancelling. A shared neutral serving a room full of workstations can run hotter than the phase conductors. For IT loads we run separate neutrals.
What we need to size it
- Nameplate rating of the equipment, not the marketing spec
- Receptacle type it expects, including any locking configuration
- Inrush on motors and compressors, which sets the breaker not the run current
- Distance from the panel, which decides conductor size for voltage drop
- Whether it needs an A and B feed from separate panels
Commercial lighting installations
Most lighting jobs we get called for are LED retrofits where someone has been quoted a fixture count and nothing else. The fixture count is the easy part. Getting the light levels right for the task is what decides whether people complain afterwards.
| Space | Typical design target |
|---|---|
| Warehouse aisles | 100 to 200 lux |
| Pick and pack | 300 to 500 lux |
| General office | 300 to 500 lux |
| Retail sales floor | 500 to 750 lux |
| Inspection and detail work | 750 to 1000 lux |
| Loading dock | 200 to 300 lux |
347V high bay is standard here. In buildings on a 600V service, high bay and exterior lighting usually run at 347V. Fixtures have to be ordered for it. This is the single most common ordering mistake we see on retrofits quoted by out-of-province suppliers.
Controls are where the savings actually are. Swapping metal halide for LED cuts the draw. Occupancy sensing in aisles that are empty most of the shift, daylight harvesting near skylights and clerestory glazing, and a time clock on the exterior and signage is what compounds it.
Also covered
- Emergency and exit lighting, including annual egress testing
- Exterior wall pack, pole and parking lighting on photocell and contactor control
- Illuminated signage circuits and timers
- Accent and display lighting for retail and hospitality
ESA code corrections and defect notices
If the Electrical Safety Authority has inspected and issued a defect notice, there is a correction deadline attached to it. We scope the corrections, get them done by a Licensed Electrical Contractor, and get the work re-inspected.
Outstanding ESA orders also turn up at the worst possible moment, usually during a lease negotiation or a sale. If you are taking on a space, it is worth checking before you sign rather than after.
What we find most often
- Double-tapped breakers, two conductors under a lug rated for one
- Missing bonding on panels, raceway, or equipment enclosures
- Junction boxes buried above a hard ceiling with no access
- Flexible cord used as permanent wiring for fixed equipment
- No panel directory, or one that has not matched reality in years
- Missing blanks and covers leaving live parts reachable
- Less than a metre of clear working space in front of the panel, usually because storage crept in
- Wrong cable rating in a plenum, FT4 where the Code calls for FT6
The last one crosses into our own trade. The Canadian Electrical Code uses FT4 and FT6 flame ratings where a US specification calls out CMR and CMP, and Ontario inspectors look for the Canadian marking. More on that in our Cat6A cabling guide.
Equipment and appliance circuits
New equipment arrives and there is nothing to plug it into, or it is running on an extension cord from the next room. This is the most common single-visit job we do.
| Load | What decides the circuit |
|---|---|
| Commercial kitchen | Individual circuits per appliance, GFCI protection, often 208V single or three-phase |
| HVAC and rooftop units | Motor inrush, local disconnect within sight of the unit |
| Compressors and machinery | Starting current, overload protection, three-phase balance |
| EV charging | Continuous load at 125 percent, load management where the service is tight |
| Server and network racks | L5-30R or L6-30R for the UPS, dual feeds where it matters |
| Production and AV | Clean ground, isolated runs away from motor loads |
Where the equipment is IT or AV, the circuit is only half the job. The rack, the bonding and the pathway have to line up with it, which is covered on our rack and cabinet installation page.
Where we work
Looking for the full electrical picture including fit-outs and comms room power? Start at commercial electrical services. For the western GTA specifically, see our Mississauga electrician page. For the low-voltage side, see network cabling in Toronto.
Send us the panel and the problem
A photo of the panel with the door open, and a line about what you are trying to add or fix, is usually enough for us to tell you whether this is a circuit, a panel or a service job. Free quotes on commercial work in our service area.
All electrical work is performed by ECRA/ESA-Licensed Electrical Contractors.
Commercial electrical contractor FAQ
Do I need a 200A or a 400A service?
It depends on the connected load and what you plan to add, not on the size of the space. A load calculation to CEC Section 8 against your actual equipment list settles it. Upsizing later costs far more than sizing correctly once, so the calculation is worth doing before the quote.
How long does a panel upgrade take and how much outage is involved?
Most commercial panel changes are a one to two day job with the power off for part of it. The outage is planned into a window that suits you, usually an evening or a weekend. Where continuity is critical, a temporary supply or a staged changeover is priced separately.
What is the difference between 120/208V and 347/600V?
They are the two common Ontario commercial service configurations. Smaller tenancies usually run 120/208V three-phase. Larger commercial and industrial buildings run 347/600V, with lighting fed at 347V. Equipment specified for the US equivalents of 277/480V will not drop in, which is a common ordering mistake on retrofits.
Do I actually need an isolated ground circuit?
Usually not. Isolated ground made sense when equipment was sensitive to ground noise. Modern switch-mode power supplies rarely benefit. We install it where the equipment manufacturer specifies it and tell you when it is not worth the extra conductor.
ESA has issued us a defect notice. What now?
There is a correction deadline attached to it. Send us the notice and a photo of the panel. We scope the corrections, have them completed by a Licensed Electrical Contractor and arrange re-inspection.
Can you quote an LED retrofit from a fixture count?
We can, but we would rather not quote from a count alone. The count tells you the cost and nothing about whether the light levels will be right for the task. A short look at the space avoids the retrofit that is cheaper and worse than what it replaced.
What lighting levels should a warehouse have?
Typical design targets are roughly 100 to 200 lux in storage aisles, 300 to 500 lux where people are picking and packing, and 200 to 300 lux at a loading dock. The right number depends on the task, the rack height and how much daylight the building gets.
Is Cablify a licensed electrical contractor?
Cablify is a low-voltage and systems contractor. All electrical work on our projects is performed by ECRA/ESA-Licensed Electrical Contractors. We scope the work, hold the drawings and the schedule, and coordinate it with the cabling and security scope.
Do you do residential work?
Some, in the western GTA, mainly panel upgrades and EV charger circuits. The focus of this page is commercial and industrial. For homes in Mississauga, Oakville or Burlington see our Mississauga electrician page.