Project capacity guide
Do you need 200 amps for a backyard suite?
Electrical-capacity planning for a residential backyard suite project.
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.
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 2026-08-31.
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.
HAUSE Capacity Check
Start with what your home needs to support.
Get a transparent electrical-capacity pre-check before deciding whether to retain, manage or upgrade the service.