What are the electrical code requirements for a secondary suite or in-law suite in New Brunswick?

Electrical Code Requirements for Secondary Suites in New Brunswick

Secondary suites — also called in-law suites, garden suites, or accessory dwelling units — are increasingly popular across New Brunswick as homeowners look to house aging parents, generate rental income, or address the province's housing shortage. The electrical requirements for these suites are more complex than a typical renovation because you're essentially creating a separate dwelling unit within or attached to an existing home.

What Defines a Secondary Suite Electrically

Under the Canadian Electrical Code and New Brunswick building regulations, a secondary suite is a self-contained living unit with its own:

• Kitchen or cooking facilities (minimum a cooktop and sink)


• Bathroom


• Sleeping area


• Separate entrance (in most NB municipalities)

Once a space meets these criteria, it triggers full residential electrical requirements for the suite — not just the lighter standards that apply to a bedroom addition or finished basement.

Electrical Panel Requirements

Option 1: Dedicated sub-panel for the suite (most common)

A separate sub-panel dedicated to the secondary suite is the standard approach in New Brunswick. This provides clear separation of circuits, easier load management, and the ability to install a separate meter if desired.

• Minimum sub-panel size: 60 amps for a small suite (bachelor/1-bedroom under 500 sq ft with electric cooking but no electric heat). Recommended: 100 amps for future flexibility.
• 100-amp sub-panel for larger suites or suites with electric baseboard heat, which is common in New Brunswick where natural gas isn't available in many areas.
• Feeder wire from main panel: 6 AWG copper for 60A, 3 AWG copper for 100A
• Cost: $1,500-$3,500 for the sub-panel installation, depending on distance from main panel

Option 2: Separate electrical service

Some municipalities in New Brunswick allow (or require) a completely separate electrical service with its own meter for the secondary suite. This is more common for detached secondary suites (garden suites, converted garages) than for suites within the main house.

• Requires NB Power to install a second meter base
• Separate 100-200 amp panel
• Allows individual billing — important for rental suites
• Cost: $4,000-$8,000 including NB Power connection fees
• Check with your municipality — some New Brunswick communities require separate metering for rental suites

Main Panel Assessment

Before adding a secondary suite, your main panel must have sufficient capacity to supply the suite's sub-panel:

• 200-amp main service: Can typically support a 60-100 amp sub-panel for the suite, provided existing loads leave adequate capacity. Most post-1990 New Brunswick homes have 200-amp services.
• 100-amp main service: Almost certainly needs upgrading to 200 amps before adding a suite. Common in pre-1990 New Brunswick homes, especially in Moncton's north end, older Saint John neighbourhoods, and smaller communities. Upgrade cost: $2,500-$4,500.
• 60-amp fuse panel: Definitely requires a full service upgrade. These panels don't have the capacity or the safety features needed. Budget $3,000-$5,000.

Required Circuits for the Suite

The CEC requires the secondary suite to have the same minimum circuits as any dwelling unit:

Kitchen:

• 2 dedicated 20-amp circuits for countertop receptacles (12 AWG wire)


• 1 dedicated circuit for refrigerator (15 or 20 amp)


• 1 dedicated circuit for dishwasher (if installed)


• 1 dedicated circuit for range/cooktop (40-50 amp, 240V for electric; 15 amp for gas ignition)


• 1 dedicated circuit for microwave (if built-in, 20 amp)

Bathroom:

• 1 dedicated 20-amp circuit for bathroom receptacles


• GFCI protection on all bathroom outlets


• Exhaust fan (can share lighting circuit)

Laundry (if included):

• 1 dedicated 20-amp circuit for washing machine


• 1 dedicated 30-amp, 240V circuit for electric dryer

General:

• Lighting circuits for all rooms (15 amp)


• General receptacle circuits (15 amp, spaced per CEC — every 1.8m along walls)


• Dedicated 15-amp circuit for furnace/heating system


• Smoke and CO detector circuits (can be interconnected with main house)

Heating (if electric):

• Dedicated circuits for baseboard heaters — typically 240V, sized to the heater wattage


• A 1-bedroom suite with electric baseboard heat may need 4,000-8,000 watts of heating, requiring 20-40 amps of dedicated 240V heating circuits

Safety Requirements

Smoke and carbon monoxide detectors:

• Smoke detectors required in every bedroom, outside each sleeping area, and on every level of the suite


• CO detectors required outside sleeping areas if the suite has fuel-burning appliances or an attached garage


• Detectors must be hardwired with battery backup (not battery-only)


• Interconnection: When one alarm sounds, all alarms in the suite must sound. Some municipalities require interconnection with the main house detectors as well.

GFCI protection:

• Bathroom receptacles


• Kitchen receptacles within 1.5m of a sink


• Laundry receptacles


• All receptacles in unfinished areas (utility rooms, mechanical rooms)


• Outdoor receptacles serving the suite

AFCI protection:

• Required on all bedroom circuits (CEC 2018+)


• Recommended for living areas

Emergency egress lighting:

• Not required for most residential secondary suites, but some municipalities require illuminated exit paths

Fire Separation Requirements (Affects Electrical)

New Brunswick building code requires fire separation between the main dwelling and the secondary suite — typically a 30-minute or 1-hour fire-rated assembly. This directly affects electrical work:

• All electrical penetrations through fire-rated walls and ceilings must be fire-stopped using approved fire-stop sealant or putty pads around electrical boxes
• Electrical boxes in fire-rated walls must be installed with minimum 600mm (24 inch) separation between boxes on opposite sides of the wall, or use fire-rated electrical boxes
• Recessed lights in fire-rated ceilings must be IC-rated (insulation contact) and covered with fire-rated enclosures

Failing fire separation requirements is one of the most common reasons secondary suite inspections fail in New Brunswick.

Permit and Inspection Process

Building permit: Required from your local municipality. Cost varies — typically $200-$500 in New Brunswick municipalities.

Electrical permit: Required from TSANB. Cost: $100-$200 for a secondary suite scope.

Inspections: Multiple inspections are typically required:

Rough-in inspection — After wiring is run but before walls are closed (drywall, insulation). TSANB inspector verifies wire routing, box placement, circuit layout, proper stapling, and fire-stopping.

Final inspection — After everything is connected and operational. Tests GFCI function, smoke/CO detectors, circuit identification, grounding, and overall code compliance.

Zoning approval: Check your municipal zoning bylaws before starting. Not all zones in every New Brunswick municipality permit secondary suites. Moncton, Fredericton, and Saint John have all updated their bylaws in recent years to allow secondary suites in more residential zones, but restrictions vary.

Total Electrical Cost Estimate

| Component | Cost Range |
|-----------|------------|
| Main panel upgrade (if needed) | $2,500-$4,500 |
| Sub-panel installation (100A) | $1,500-$3,500 |
| Kitchen circuits (5-7 circuits) | $2,000-$4,000 |
| Bathroom circuit + GFCI | $400-$800 |
| General circuits (lighting + receptacles) | $1,500-$3,000 |
| Electric heat circuits (if needed) | $800-$2,000 |
| Smoke/CO detectors (hardwired) | $300-$600 |
| TSANB permits + inspections | $200-$400 |
| Total (without main panel upgrade) | $6,700-$14,300 |
| Total (with main panel upgrade) | $9,200-$18,800 |

The electrical component typically represents 25-35% of the total secondary suite construction cost in New Brunswick. For a complete in-law suite conversion of an existing basement, total project costs (all trades) typically run $40,000-$80,000 depending on the level of finish.

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