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Replacing a building’s switchgear
For building owners and managers: what the main electrical equipment includes, the shutdown to plan for tenants, and coordinating with Hydro-Québec.
In short
Between Hydro-Québec’s network and the meters, a building has its service equipment: that’s what gets replaced when the main supply is redone.
- It includes the transformer cabinet, the distribution box, the service box, the disconnecting means and the meter base, among others.
- The request to Hydro-Québec is submitted by the master electrician.
- At STM-Électrique, the shutdown usually lasts about 6 hours.
- The price is in the quote.
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What the main equipment includes
Hydro-Québec calls the “customer’s service” all the equipment located between the connection point and the metering equipment.
| Item | What it is |
|---|---|
| Transformer cabinet | An indoor metal cabinet that holds transformers and other Hydro-Québec equipment, with the meters above it |
| Distribution box | A metal box where the feeder runs are connected |
| Disconnecting means | What cuts the current in a circuit |
| Metering centre | A metal enclosure that can hold a service box, protection or disconnecting devices, and meter bases |
This equipment can be in a meter room, a room set up in the building to hold it.
Voltage and capacity
At low voltage, Hydro-Québec offers 120/240 V single-phase or 347/600 V three-phase.
The supply comes directly from the line when the service boxes add up to 600 A or less.
A building gets only one Hydro-Québec service, with some exceptions.
EV chargers or another load to add? According to the Régie du bâtiment, the feeders and the service upstream then have to be recalculated. For a charger project, the first step is to have the building’s electrical capacity assessed: see EV chargers in apartment buildings.
A building to assess?
We look at the equipment, we do the calculation, and the price is in the quote.
Send my quote requestThe steps with Hydro-Québec
The master electrician files the service request with Hydro-Québec at the planning stage, then the declaration of work once the building is ready to be connected.
Each service box, transformer cabinet, panel and meter base carries an identification mark put on by the master electrician: the building’s address or the unit number.
The Hydro-Québec forms are ours to fill out, all of them.
The power shutdown
Replacing a building’s main equipment requires a shutdown. At STM-Électrique, it usually lasts about 6 hours, as for a service entrance replacement.
The duration of the work is given to you with the quote.
For tenants: before major repairs or improvements in a dwelling, the Tribunal administratif du logement requires 10 days’ written notice. To find out which notice to give, check with the Tribunal.
What we do
Our master electricians work in residential and commercial settings.
Before any proposal, our master electricians calculate the building’s load.
The price is in the quote, which is free.
Frequently asked questions
What is a building’s service equipment?
All the equipment between Hydro-Québec’s connection point and the meters: the transformer cabinet, the distribution box, the service box, the disconnecting means and the meter base, among others.
How long will tenants be without power?
At STM-Électrique, usually about 6 hours. The duration of the work is given with the quote.
Who deals with Hydro-Québec?
The master electrician: they file the service request and the declaration of work. At STM-Électrique, they fill out all the forms.
Do tenants need to be notified?
For major repairs or improvements in a dwelling, the Tribunal administratif du logement requires 10 days’ written notice. Check with the Tribunal for your situation.
What voltage for a building?
At low voltage, Hydro-Québec offers 120/240 V single-phase or 347/600 V three-phase.
A building to assess?
We look at the equipment, we handle Hydro-Québec, and the price is in the quote.
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Sources
Consulted on October 28, 2026.
- Hydro-Québec, standard E.21-10 (Blue Book), February 2021 (in French)
- Régie du bâtiment du Québec, quality control guide for electrical installation work (in French)
- Régie du bâtiment du Québec, new calculation required when loads are added (in French)
- Tribunal administratif du logement, notice of major repairs or improvements (in French)