CONSTRUCTION POWER · TORONTO & THE GTA
Generator Power and Temporary Power for Construction Sites in Toronto
A construction site runs on temporary power long before it runs on its own — and the Code treats that system as a full electrical installation. Here is how we set it up across Toronto and the GTA.
Grounding the generator properly
A generator is a power source, not an appliance — it has to be grounded and bonded like one. Section 76 covers temporary wiring, and Rule 76-004 sends grounding and bonding back to Section 10, the same rules as a permanent service. Three things decide whether it is done right. First, the electrode: a proper grounding conductor to a grounding plate buried in the earth — Section 10 puts a plate at least 600 mm below grade — not a wire clipped to the trailer hitch. Second, bonding: frame, distribution, and every metal enclosure tied together — that path back is what trips a breaker on a fault. Third, the neutral: the machine’s label states NEUTRAL BONDED TO FRAME or NEUTRAL FLOATING, and ESA Bulletin 10-10-10 builds the grounding rules on that marking — a bonded-neutral machine connects directly to the grounding electrode.
Running power to the construction trailers
The generator or temporary service feeds a main distribution centre, and feeders run from there to each trailer and work area. Distribution centres must be weatherproof, mounted upright, and big enough for their load (Rule 76-008); feeders run in armoured cable, or outdoor extra-hard-usage cable with its own bonding conductor, protected from mechanical damage the whole way (Rule 76-010) — cables protected where trucks cross, and out of standing water.
Each trailer gets its own feed and disconnect — a steady all-day load of heat, lights, and computers — so one trailer’s problem does not darken the row.
The big diesels: 480 and 600 volts, not just 120/208
Trailers sip power. Tower cranes, hoists, and heavy equipment drink it — at higher voltages. The large towable diesels are voltage-selectable: 120/208 and 120/240 for trailers and tools, 277/480 three-phase for equipment, and 600 volts natively on some units, or through a transformer. On one winter site, our 70 kVA towable setup fed three voltages at once: a transformer and a dedicated 600-volt disconnect delivered 347/600V and 480V at the same time, plus low-voltage output. Sizing and voltage follow the site’s load list, not whatever showed up on the truck.
What the rules require on an Ontario site
- GFCI protection. Every 15 and 20 amp receptacle provided for construction power must be protected by a Class A ground fault circuit interrupter (Rule 76-016). No exceptions for “it’s only temporary.”
- Kept separate, built for outdoors. Temporary installations stay separate from the building’s permanent system except by special permission (Rule 76-014), and outdoor service equipment must be lockable, restricted to authorized people, and weather-protected (Rule 76-006).
- ESA notification and inspection. Under Ontario’s Rule 2-004, the contractor files a notification with the Electrical Safety Authority before work starts, and ESA’s connection authorization comes before the installation is used. Bulletin 2-3-19 is blunt: all new installations require a notification, and temporary power is a new installation. The work is done by a licensed electrical contractor (O. Reg. 570/05), and the temporary wiring comes out when permanent power takes over.
Lighting the work itself
Site lighting is not decoration. In a Toronto winter, crews start before daylight and finish after it — stairs, hoist areas, and work faces need light all shift.
One protection we like: lighting branch circuits stay entirely separate from power branch circuits (Rule 76-012), so a tripped saw or heater never blacks out the site, and lighting loads are capped at 80% of the breaker rating. In practice: even coverage on stairs and edges, fixtures where a lift won’t take them out, and light at the distribution points.
Pedestrian protection lighting
Developments go up next to sidewalks that never close, and when hoarding and a covered walkway go in, the walkway becomes part of the site’s electrical job.
A covered walkway in shadow is its own hazard. Pedestrian protection lighting means the full length lit evenly — no dark pockets — on weatherproof fixtures that can take a knock, running nightly on a timer or photocell, and maintained: a burnt-out section is a complaint and a liability. We install and maintain it as part of the temporary power package, never as an afterthought.
What 3e does on a site
One call covers it: generator hookups and grounding, temporary services and distribution, trailer feeds, site lighting, and covered-walkway lighting. We file the ESA notification, stand the inspection, and maintain the setup through the build — engineer-led, licensed, quoted in writing before we start.
From our sites
Tap a photo to view it full size.
3e project — towable diesel generator, temporary site power.
3e project — output lugs, and the “Neutral Bonded to Frame” marking that decides how the machine is grounded.
3e project — the 600-volt disconnect. Its notice reads: for 347/600 volt output, 600 volts is available from this disconnect and 480 volts from the output lugs at the same time.
3e project — the 70 kVA WhisperWatt that fed a winter site at three voltages.
3e project — generator power to a site office trailer.
3e project — from the field: this winter setup carried two transformers and delivered 600, 480 and 120 volts on the one site. Its 600-volt disconnect and the 70 kVA WhisperWatt behind it are photos 3 and 4 above.
Frequently asked questions
Does a generator on a construction site need to be grounded?
Yes — Section 76 requires grounding and bonding to Section 10, the same standard as a permanent service.
Do construction site receptacles need GFCI protection?
Yes — Rule 76-016 requires construction-power receptacles (the standard 15 and 20 amp outlets) to be protected by Class A GFCIs.
Does temporary power need an ESA inspection in Ontario?
Yes. The contractor files a notification with the Electrical Safety Authority before work starts, and ESA’s connection authorization comes before the installation is used.
Can site power be connected into the building under construction?
Not as a rule — Rule 76-014 keeps temporary installations separate from the permanent one, except by special permission.
Power your site from day one
Tell us the site, the schedule and the load list — trailers, cranes, hoists, lighting. See what our construction site temporary power service covers, or send the details and we will size it and quote it in writing.
Request a QuoteWe quote it. You approve it. We do it.
