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Adding a unit: meter and panel
Basement unit, house converted into a duplex: a second meter or a subpanel, what decides it, and who handles the steps with Hydro-Québec.
In short
Adding a unit to a house is first a question of meters: Hydro-Québec allows only one metering point per customer, for a given location and voltage.
- Two accounts, two meters; one account, one meter.
- When a single delivery point is added to an existing installation, one more meter base is allowed.
- The new load means redoing the load calculation for the service.
- At STM-Électrique, an added unit usually gets its own Hydro-Québec meter.
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Second meter or subpanel
There are two ways to power a unit added in the basement or upstairs.
| Second meter | Subpanel | |
|---|---|---|
| Hydro-Québec meter | One more, for the unit | The house’s meter |
| Account | One per unit | One for both |
| What gets added | A meter base and a panel for the unit | A panel fed from the house’s panel |
The second meter follows Hydro-Québec’s rule: one metering point per customer. If the unit has its own account, it has its own meter.
Either way, each unit must have its own identified supply and its own protection.
What decides it
Who pays for the electricity. A tenant with their own Hydro-Québec account is one more customer, so one more meter.
The building. Hydro-Québec installs only one service per building. A space separated from its neighbours by firewalls counts as a separate building.
The city. Some cities regulate intergenerational units. In Laval, a bylaw defines one as rooms without an independent electrical service, or without a separate exit, or without a separate civic number. Check with your city before choosing.
Service capacity
An added unit is an added load. According to the Régie du bâtiment, adding a load means redoing the calculation for the feeders and the service upstream.
Our master electricians do the load calculation before proposing anything.
The calculation tells whether the current service is enough or has to be upgraded. The details are in our guides on 320 or 400 amp service and on the load calculation.
A unit to add?
We do the load calculation, we handle Hydro-Québec, and the price is in writing before the work.
Send my quote requestThe paperwork with Hydro-Québec
The service request and the declaration of work are submitted to Hydro-Québec by the master electrician.
The request is made when the work is planned; the declaration, once the installation is ready to be connected.
The master electrician also labels the equipment: the address or unit number appears on each meter base, service box and panel.
Hydro-Québec installs the meter and puts the installation in service.
What we do
An added unit usually gets its own Hydro-Québec meter.
We take care of all the Hydro-Québec forms.
The unit’s panel goes in a suitable location: never in a clothes closet, a bathroom or a stairwell. No breaker handle is more than 1.7 m above the floor.
For who owns the mast, the meter base and the meter, see who pays for what.
Frequently asked questions
Does a basement unit need a second meter?
If the unit has its own Hydro-Québec account, yes: only one metering point is allowed per customer. At STM-Électrique, an added unit usually gets its own meter.
Can a subpanel be enough?
On Hydro-Québec’s side, a single account means a single meter: the unit is then fed by a panel connected to the house’s panel. Whether that setup suits your unit is for the master electrician’s visit and your city’s rules to say.
Can a meter base be added next to the house’s?
Yes. When a single delivery point is added to an existing installation, one more individual meter base is allowed.
Who makes the request to Hydro-Québec?
The master electrician submits the service request and the declaration of work. We take care of all the forms.
Is my electrical service big enough?
Only the load calculation can tell: adding a load means redoing the service calculation.
Where does the unit’s panel go?
In a suitable location, never in a clothes closet, a bathroom or a stairwell, with no breaker handle more than 1.7 m above the floor.
A unit to add?
We do the load calculation, we handle the steps with Hydro-Québec, and the price is in writing before the work.
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Get a quote: meter and service entrance
Sources
Consulted on October 28, 2026.
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