What gauge wire do I need for a basement suite electrical in Calgary?

A Calgary basement suite requires multiple wire gauges depending on the circuit type — 14/2 NMD90 for 15-amp lighting circuits, 12/2 for 20-amp kitchen and general-use outlets, and heavier gauges (10/3, 8/3, or 6/3) for dedicated appliance circuits like a range, dryer, or sub-panel feed. There is no single wire gauge for an entire suite; each circuit must be sized appropriately for its load, and your licensed electrician will specify the correct gauge for every run based on the Canadian Electrical Code requirements.

A typical legal basement suite in Calgary requires approximately 10 to 18 circuits depending on the layout and amenities. Here is how the wire gauges break down by circuit type. General lighting circuits use 14/2 NMD90 wire on 15-amp breakers — you will need at least 2 to 3 lighting circuits to serve the bedroom(s), living area, bathroom, and hallway. Kitchen counter circuits require 12/2 wire on 20-amp breakers, with a minimum of two dedicated small appliance circuits required by code. Bathroom outlets use 12/2 wire on a dedicated 20-amp GFCI-protected circuit. General living area outlets can use either 14/2 on 15-amp circuits or 12/2 on 20-amp circuits — many electricians default to 12/2 for future flexibility. The refrigerator gets its own dedicated circuit, typically 12/2 on 20 amps. An electric range requires 8/3 wire on a 40-amp breaker or 6/3 on a 50-amp breaker. An electric dryer uses 10/3 wire on a 30-amp breaker. The bathroom exhaust fan and kitchen range hood each need their own circuits, typically 14/2 on 15 amps.

The sub-panel feed is the largest wire in the installation. Most basement suites are served by a 60-amp or 100-amp sub-panel fed from the main panel upstairs. A 60-amp sub-panel feed uses 6/3 copper wire, while a 100-amp feed uses 3/3 or 2/3 copper wire (or aluminum equivalent if approved by your electrician and local inspector). The sub-panel itself costs $400 to $900 for the equipment, and installation of the complete sub-panel with feed wire typically runs $1,000 to $2,200.

Calgary has specific requirements for legal basement suites that go beyond basic wiring. The suite must have interconnected hardwired smoke detectors and carbon monoxide alarms connected to the main home's alarm system — this uses 14/3 wire with a dedicated circuit. Bedroom windows must meet egress requirements (this is a building code requirement rather than electrical, but it affects the overall suite approval). The suite needs its own electrical panel or clearly marked sub-panel so occupants can access breakers in an emergency without entering the upstairs unit.

The total electrical cost for a basement suite in Calgary typically runs $5,000 to $12,000 depending on the size, number of rooms, and whether the main panel upstairs has capacity for the sub-panel feed or needs an upgrade. If your home has a 100-amp main panel, adding a basement suite almost certainly requires a panel upgrade to 200 amps ($1,800 to $4,500 additional), because the combined load of two dwelling units exceeds what a 100-amp service can safely deliver.

All basement suite electrical work in Calgary requires an electrical permit, and the City of Calgary has a secondary suite permit process that includes both building and electrical inspections. A Safety Codes Officer inspects the rough-in wiring before drywall and the finished installation after trim-out. The permit process for a secondary suite is more involved than a simple renovation because the suite must meet all code requirements for a separate dwelling unit.

Verify your electrician is experienced with Calgary secondary suite requirements, carries WCB Alberta coverage, and is familiar with the City of Calgary's specific secondary suite permitting process. Calgary Electrical Services can match you with electricians experienced in basement suite wiring.