How do I wire a garage for both 120V and 240V circuits on the same panel in NB?

All garage electrical work in New Brunswick requires a licensed electrician and electrical permit — this is not a DIY project. However, understanding how mixed-voltage garage electrical systems work helps you plan your project and communicate effectively with your electrician.

A properly designed garage electrical system uses a sub-panel fed from your main house panel to distribute both 120V and 240V circuits throughout the garage. The sub-panel receives power through a single large cable (typically 60-amp or 100-amp service) but can then distribute multiple smaller circuits at different voltages to serve your garage's specific needs.

The sub-panel approach is standard in NB garages because it provides flexibility, safety, and code compliance. Your electrician will install a two-pole breaker in your main house panel (sized for the sub-panel's capacity) and run a cable containing two hot wires, one neutral, and one ground wire to the garage sub-panel. Inside the sub-panel, the two hot wires connect to separate bus bars, giving you access to both 120V (using one hot wire and neutral) and 240V (using both hot wires) for different circuits.

Common 120V garage circuits include: general lighting and outlets (15-amp or 20-amp circuits with GFCI protection), garage door opener (dedicated 15-amp circuit), and workshop outlets (20-amp circuits for power tools). NB electrical code requires GFCI protection on all garage receptacles, and many electricians install GFCI breakers in the sub-panel rather than GFCI outlets throughout the garage — this provides protection for the entire circuit and is more reliable in dusty garage environments.

Common 240V garage circuits include: electric vehicle Level 2 chargers (typically 40-amp or 50-amp circuits), electric garage heaters (sized to the heater's requirements, often 20-amp to 30-amp), welders and large workshop equipment (30-amp to 50-amp depending on equipment), and electric vehicle charging outlets (14-50R outlets are standard for portable EV chargers). Each 240V circuit uses both hot wires from the sub-panel, providing 240 volts between them.

Sub-panel sizing depends on your total electrical load. A basic garage with lighting, outlets, and garage door opener can operate on a 60-amp sub-panel. Add an EV charger and electric heater, and you'll need a 100-amp sub-panel. Large workshops with multiple 240V tools may require 125-amp or 200-amp sub-panels. Your electrician will calculate the load based on your specific equipment and future plans — it's much cheaper to install adequate capacity initially than to upgrade later.

The cable run from house to garage must be sized for the sub-panel capacity and burial depth. For a detached garage, this typically means underground cable in conduit or direct-burial cable rated for wet locations. In NB's climate, the cable must be buried below frost depth (4-5 feet) or installed in a heated building envelope. Attached garages can use interior routing through basements or crawl spaces, which is less expensive but requires proper fire-stopping where the cable penetrates the fire separation between garage and house.

Grounding and bonding are critical safety requirements in garage electrical systems. The sub-panel must have a separate grounding electrode (ground rod) at the garage, and all metal components — garage door tracks, overhead door operators, metal workbenches, and conduit systems — must be properly bonded to prevent electrical shock hazards. This is especially important in garages where moisture and metal surfaces create increased shock risks.

Planning considerations for mixed-voltage garage wiring: Install more circuits than you currently need — adding circuits to an existing sub-panel is inexpensive during initial installation but costly later. Plan outlet locations for both current and future equipment — EV chargers, air compressors, and workshop tools have specific location requirements. Consider smart panel options that allow remote monitoring and control of individual circuits. Include adequate lighting circuits — garages need more light than most homeowners initially plan, and good lighting improves safety and functionality.

When to Hire a Professional: All garage electrical work requires a licensed electrician in New Brunswick. The electrical permit, load calculations, panel sizing, cable routing, grounding system, and final inspection must be completed by qualified professionals. Electrical work in garages involves additional safety considerations due to potential flammable vapours from vehicles and stored materials — this isn't the place for DIY electrical experiments.

Need help finding a qualified electrician for your garage project? New Brunswick Garages can match you with electrical contractors experienced in garage wiring through the New Brunswick Construction Network.