Project capacity guide
Do you need 200 amps for a backyard suite?
Electrical-capacity planning for a backyard suite at home.
Short answer
A backyard suite does not automatically require 200A service. The decision depends on separate building demand, feeder or service design, heating, water heating and utility/municipal requirements.
Key takeaways
01Start with equipment specifications and the home’s current demand.
02Panel space does not prove service capacity.
03The project should be assessed before equipment is purchased or installation is booked.
What determines capacity
The contractor needs to review separate building demand, feeder or service design, heating, water heating and utility/municipal requirements. The applicable calculation and local permit rules determine the acceptable design.
Alternatives to a service increase
the best design may involve a feeder, separate service or coordinated property plan. Any alternative still needs to be approved for the equipment, installation and jurisdiction.
What to prepare
Bring the equipment model or expected rating, service-size clues, existing major loads, panel-space information and future project plans.
Field notes / decision evidence
Start at the second building
A detached suite raises a feeder-versus-service design question before it raises a 200A question.
Building demand
List the suite's heating, cooling, water heating, cooking and laundry equipment. Include the main home's loads in any shared-service assessment.
Supply route
Ask whether a feeder from the home or a separate utility service is feasible, and which trenching or restoration work each option creates.
Ownership and permits
Confirm the municipal and utility requirements for a separate building and meter arrangement before comparing quotes.
Illustrative scenarioExample only: a backyard suite with a separate utility service is a different project from one supplied by a feeder, even if the interior equipment looks similar.
Decision table
What the evidence changes
- Automatic 200A requirement
- No
- Decision evidence
- Applicable load calculation + equipment information
- Possible paths
- Existing service, distribution change, management or service upgrade
Typical project sequence
From question to documented work
- 01Choose equipment concept
- 02Check existing service and loads
- 03Complete calculation
- 04Confirm permit / utility path
- 05Install and inspect
Sequence and responsibilities vary by jurisdiction, utility and scope.
Evidence
Sources and verification
Published by the 200AmpPanel.ca Research Team, a HAUSE specialist property. Updated 2026-09-29.
Questions
Frequently asked
Can a 100A home support a backyard suite?
Sometimes. The service size alone cannot answer; existing demand and project design matter.
What should I do next?
Use the Capacity Check to organize what you know, then have a qualified electrical contractor complete the assessment required for the property and jurisdiction.
Your next step
Bring the right facts to the first conversation.
Record the visible service clue, planned equipment and any relevant documents. The free brief organizes your questions; a qualified person verifies capacity and scope.