What are the NB code requirements for a disconnect switch at a detached garage?

The NB Electrical Code requires a disconnect switch at every detached garage that receives electrical service, and it must be readily accessible from outside the building before entering the structure.

For detached garages in New Brunswick, the electrical disconnect (also called a service disconnect or main breaker) must be installed on the exterior of the building or immediately inside the entry door where it's accessible without having to walk through the garage space. This safety requirement ensures that electrical power to the garage can be shut off quickly in an emergency — whether for fire suppression, electrical work, or accident response — without having to enter a potentially dangerous space.

The disconnect must be rated for the full electrical load of the garage and clearly marked as the main electrical disconnect. Most residential detached garages in NB use a 60-amp or 100-amp disconnect, depending on the planned electrical load. A basic garage with lighting, outlets, and a garage door opener typically needs 60 amps, while a workshop garage with 240V outlets for welders or EV charging requires 100 amps or more.

Installation requirements are specific: the disconnect must be mounted between 1.2 and 2 metres above grade (roughly 4 to 6.5 feet), protected from weather with an appropriate enclosure rated for outdoor use, and have at least 1 metre of clear working space in front of it. The disconnect cannot be located where a vehicle might strike it, so placement beside the service door rather than in front of overhead doors is typical.

The electrical feed to the garage — whether underground cable or overhead service — must connect to this disconnect first before feeding any sub-panel or circuits inside the garage. Underground feeds are more common in NB because they're protected from ice storms and high winds that regularly damage overhead lines. Underground electrical cable must be buried at least 600mm (24 inches) deep in NB, or deeper if crossing under driveways or areas subject to vehicle traffic.

All electrical work requires permits and inspection by a licensed New Brunswick electrician. The disconnect installation, underground or overhead service installation, and any sub-panel or circuit work inside the garage must be inspected before the electrical service can be energized. Attempting to install garage electrical without proper permits and professional installation violates the NB Electrical Code and can void homeowner's insurance coverage.

For garages with workshops, EV charging, or heating equipment, many electricians recommend installing the exterior disconnect plus a sub-panel inside the garage for convenience. This allows individual circuits to be controlled from inside while maintaining the required exterior disconnect for emergency shutoff.

Need help finding a licensed electrician for your garage electrical work? Browse electrical contractors through the New Brunswick Construction Network directory for professionals familiar with NB code requirements and garage installations.